Pathological response in resectable non-small cell lung cancer: a systematic literature review and meta-analysis

BACKGROUND

Surrogate endpoints for overall survival in patients with resectable non-small cell lung cancer receiving neoadjuvant therapy are needed to provide earlier treatment outcome indicators and accelerate drug approval. This study's main objectives were to investigate the association among pathological complete response, major pathological response, event-free survival and overall survival and to determine whether treatment effects on pathological complete response and event-free survival correlate with treatment effects on overall survival.

METHODS

A comprehensive systematic literature review was conducted to identify neoadjuvant studies in resectable non-small cell lung cancer. Analysis at the patient level using frequentist and Bayesian random effects (hazard ratio [HR] for overall survival or event-free survival by pathological complete response or major pathological response status, yes vs no) and at the trial level using weighted least squares regressions (hazard ratio for overall survival or event-free survival vs pathological complete response, by treatment arm) were performed.

RESULTS

In both meta-analyses, pathological complete response yielded favorable overall survival compared with no pathological complete response (frequentist, 20 studies and 6530 patients: HR = 0.49, 95% confidence interval = 0.42 to 0.57; Bayesian, 19 studies and 5988 patients: HR = 0.48, 95% probability interval = 0.43 to 0.55) and similarly for major pathological response (frequentist, 12 studies and 1193 patients: HR = 0.36, 95% confidence interval = 0.29 to 0.44; Bayesian, 11 studies and 1018 patients: HR = 0.33, 95% probability interval = 0.26 to 0.42). Across subgroups, estimates consistently showed better overall survival or event-free survival in pathological complete response or major pathological response compared with no pathological complete response or no major pathological response. Trial-level analyses showed a moderate to strong correlation between event-free survival and overall survival hazard ratios (R2 = 0.7159) but did not show a correlation between treatment effects on pathological complete response and overall survival or event-free survival.

CONCLUSION

There was a strong and consistent association between pathological response and survival and a moderate to strong correlation between event-free survival and overall survival following neoadjuvant therapy for patients with resectable non-small cell lung cancer.

Neoadjuvant Trebananib plus Paclitaxel-based Chemotherapy for Stage II/III Breast Cancer in the Adaptively Randomized I-SPY2 Trial-Efficacy and Biomarker Discovery

PURPOSE

The neutralizing peptibody trebananib prevents angiopoietin-1 and angiopoietin-2 from binding with Tie2 receptors, inhibiting angiogenesis and proliferation. Trebananib was combined with paclitaxel±trastuzumab in the I-SPY2 breast cancer trial.

PATIENTS AND METHODS

I-SPY2, a phase II neoadjuvant trial, adaptively randomizes patients with high-risk, early-stage breast cancer to one of several experimental therapies or control based on receptor subtypes as defined by hormone receptor (HR) and HER2 status and MammaPrint risk (MP1, MP2). The primary endpoint is pathologic complete response (pCR). A therapy "graduates" if/when it achieves 85% Bayesian probability of success in a phase III trial within a given subtype. Patients received weekly paclitaxel (plus trastuzumab if HER2-positive) without (control) or with weekly intravenous trebananib, followed by doxorubicin/cyclophosphamide and surgery. Pathway-specific biomarkers were assessed for response prediction.

RESULTS

There were 134 participants randomized to trebananib and 133 to control. Although trebananib did not graduate in any signature [phase III probabilities: Hazard ratio (HR)-negative (78%), HR-negative/HER2-positive (74%), HR-negative/HER2-negative (77%), and MP2 (79%)], it demonstrated high probability of superior pCR rates over control (92%-99%) among these subtypes. Trebananib improved 3-year event-free survival (HR 0.67), with no significant increase in adverse events. Activation levels of the Tie2 receptor and downstream signaling partners predicted trebananib response in HER2-positive disease; high expression of a CD8 T-cell gene signature predicted response in HR-negative/HER2-negative disease.

CONCLUSIONS

The angiopoietin (Ang)/Tie2 axis inhibitor trebananib combined with standard neoadjuvant therapy increased estimated pCR rates across HR-negative and MP2 subtypes, with probabilities of superiority >90%. Further study of Ang/Tie2 receptor axis inhibitors in validated, biomarker-predicted sensitive subtypes is warranted.

Analysis of Breast Cancer Mortality in the US-1975 to 2019

Importance

Breast cancer mortality in the US declined between 1975 and 2019. The association of changes in metastatic breast cancer treatment with improved breast cancer mortality is unclear.

Objective

To simulate the relative associations of breast cancer screening, treatment of stage I to III breast cancer, and treatment of metastatic breast cancer with improved breast cancer mortality.

Design, Setting, and Participants

Using aggregated observational and clinical trial data on the dissemination and effects of screening and treatment, 4 Cancer Intervention and Surveillance Modeling Network (CISNET) models simulated US breast cancer mortality rates. Death due to breast cancer, overall and by estrogen receptor and ERBB2 (formerly HER2) status, among women aged 30 to 79 years in the US from 1975 to 2019 was simulated.

Exposures

Screening mammography, treatment of stage I to III breast cancer, and treatment of metastatic breast cancer.

Main Outcomes and Measures

Model-estimated age-adjusted breast cancer mortality rate associated with screening, stage I to III treatment, and metastatic treatment relative to the absence of these exposures was assessed, as was model-estimated median survival after breast cancer metastatic recurrence.

Results

The breast cancer mortality rate in the US (age adjusted) was 48/100 000 women in 1975 and 27/100 000 women in 2019. In 2019, the combination of screening, stage I to III treatment, and metastatic treatment was associated with a 58% reduction (model range, 55%-61%) in breast cancer mortality. Of this reduction, 29% (model range, 19%-33%) was associated with treatment of metastatic breast cancer, 47% (model range, 35%-60%) with treatment of stage I to III breast cancer, and 25% (model range, 21%-33%) with mammography screening. Based on simulations, the greatest change in survival after metastatic recurrence occurred between 2000 and 2019, from 1.9 years (model range, 1.0-2.7 years) to 3.2 years (model range, 2.0-4.9 years). Median survival for estrogen receptor (ER)-positive/ERBB2-positive breast cancer improved by 2.5 years (model range, 2.0-3.4 years), whereas median survival for ER-/ERBB2- breast cancer improved by 0.5 years (model range, 0.3-0.8 years).

Conclusions and Relevance

According to 4 simulation models, breast cancer screening and treatment in 2019 were associated with a 58% reduction in US breast cancer mortality compared with interventions in 1975. Simulations suggested that treatment for stage I to III breast cancer was associated with approximately 47% of the mortality reduction, whereas treatment for metastatic breast cancer was associated with 29% of the reduction and screening with 25% of the reduction.

Lecanemab for Patients With Early Alzheimer Disease: Bayesian Analysis of a Phase 2b Dose-Finding Randomized Clinical Trial

Importance

Bayesian clinical trial designs are increasingly common; given their promotion by the US Food and Drug Administration, the future use of the bayesian approach will only continue to increase. Innovations possible when using the bayesian approach improve the efficiency of drug development and the accuracy of clinical trials, especially in the context of substantial data missingness.

Objective

To explain the foundations, interpretations, and scientific justification of the bayesian approach in the setting of lecanemab trial 201, a bayesian-designed phase 2 dose-finding trial; to demonstrate the efficiency of using a bayesian design; and to show how it accommodates innovations in the prospective design and also treatment-dependent types of missing data.

Design, Setting, and Participants

This study was a bayesian analysis of a clinical trial comparing the efficacy of 5 lecanemab 201 dosages for treatment of early Alzheimer disease. The goal of the lecanemab 201 trial was to identify the effective dose 90 (ED90), the dose achieving at least 90% of the maximum effectiveness of doses considered in the trial. This study assessed the bayesian adaptive randomization used, in which patients were preferentially assigned to doses that would give more information about the ED90 and its efficacy.

Interventions

Patients in the lecanemab 201 trial were adaptively randomized to 1 of 5 dose regimens or placebo.

Main Outcomes and Measures

The primary end point of lecanemab 201 was the Alzheimer Disease Composite Clinical Score (ADCOMS) at 12 months with continued treatment and follow-up out to 18 months.

Results

A total 854 patients were included in trial treatment: 238 were in the placebo group (median age, 72 years [range, 50-89 years]; 137 female [58%]) and 587 were assigned to a lecanemab 201 treatment group (median age, 72 years [range, 50-90 years]; 272 female [46%]). The bayesian approach improved the efficiency of a clinical trial by prospectively adapting to the trial's interim results. By the trial's end more patients had been assigned to the better-performing doses: 253 (30%) and 161 (19%) patients to 10 mg/kg monthly and 10 mg/kg biweekly vs 51 (6%), 52 (6%), and 92 (11%) patients to 5 mg/kg monthly, 2.5 mg/kg biweekly, and 5 mg/kg biweekly, respectively. The trial identified 10 mg/kg biweekly as the ED90. The change in ADCOMS of the ED90 vs placebo was -0.037 at 12 months and -0.047 at 18 months. The bayesian posterior probability that the ED90 was superior to placebo was 97.5% at 12 months and 97.7% at 18 months. The respective probabilities of super-superiority were 63.8% and 76.0%. The primary analysis of the randomized bayesian lecanemab 201 trial found in the context of missing data that the most effective dose of lecanemab nearly doubles its estimated efficacy at 18 months of follow-up in comparison with restricting analysis to patients who completed the full 18 months of the trial.

Conclusions and Relevance

Innovations associated with the bayesian approach can improve the efficiency of drug development and the accuracy of clinical trials, even in the context of substantial data missingness.

Trial Registration

ClinicalTrials.gov Identifier: NCT01767311.

Abstract PD5-04: PD5-04 Characterizing the HER2-/Immune-/DNA repair (DRD-) response predictive breast cancer subtype: the hunt for new protein targets in a high-needs population with low response to all I-SPY2 agents

Background: In previous work we leveraged the I-SPY2 trial to create treatment response predictive subtypes (RPS) incorporating tumor biology beyond clinical HR/HER2, to better predict drug responses in an expanded treatment landscape that includes platinum agents, dual HER2-targeting regimens and immunotherapy [1]. We showed that best performing schemas incorporate Immune, DRD and HER2/Luminal phenotypes, and that treatment allocation based on these would increase the overall pCR rate to 63% from 51% using HR/HER2-based treatment selection. The RPS schema has been selected for prospective evaluation in I-SPY2. Using the RPS, one would prioritize platinum-based therapy for HER2-/Immune-/DRD+, immunotherapy for HER2-/Immune+, and dual-anti-HER2 for HER2+ that are not luminal. HER2+/Luminal patients have low response rates to dual-anti-HER2 therapy but may respond better to anti-AKT. However, there is still a considerable ‘biomarker-negative’ group of resistant cancers (HER2-/Immune-/DRD-) with very low pCR rates to all tested agents, that require a new therapeutic approach. Here we characterize the protein signaling architecture of these tumors to identify new target candidates. Methods: 987 I-SPY 2 patients from 10 arms of the trial were considered for this analysis. All have gene expression, pCR and RPS; 944 have distant recurrence free survival (DRFS) data; and 736 have reverse phase protein array (RPPA) data from laser capture microdissected tumor epithelium. These data – known collectively as the I-SPY2-990 mRNA/RPPA Data Resource - were recently made public on NCBI’s Gene Expression Omnibus [GEO: GSE196096]. We focus on HER2-/Immune-/DRD- tumors, applying Wilcoxon and t-tests to identify phosphoproteins that differ between HR+HER2-/Immune-/DRD- and other HR+HER2- tumors; and between TN/Immune-/DRD- and other TNs. The Benjamini-Hochberg (BH) method is used to adjust p-values for multiple hypothesis testing. In addition, the Kaplan-Meier method is used to estimate DRFS. Results: 201/736 I-SPY 2 patients with RPPA data are classified HER2-/Immune-/DRD- (HR+HER2-: n=138; TN: n=63). Of these, 8.5% (17/201) achieved pCR. Non-responding HER2-/Immune-DRD- had worse outcomes than responders (~75% vs. ~95% DRFS at 5 years). 60/139 phospho-proteins differ significantly between HR+HER2-/Immune-/DRD- and other HR+HER2- tumors (n=122). These tumors are relatively ‘cold’, in that 90% (54/60) of the phosphoprotein activities characterizing this group are at lower levels than in the overall HR+HER2- population; including immune (e.g. pPDL1, pJAK/STAT) and proliferation (e.g., Ki67, CyclinB1, pAURK) endpoints. Phosphoproteins showing higher levels in this subset include ERBB2 (BH p=1.7E-06), Cyclin D1 (BH p=1.4E-05), pAR (BH p=1.4E-05), and ER (BH p=3E-04). Within the TN subset, only 3/139 phospho-proteins differed significantly between TN/Immune-/DRD- and other TN tumors (n=189). These were all immune-related (pPDL1, pSTAT1, and HLA DR), with lower expression in the TN/Immune-/DRD- group. Conclusion: HR+HER2- and TN patients who are Immune-Low and DRD-Low have very low pCR rates to all tested therapeutics in I-SPY2 including standard chemotherapy, platinum, and immunotherapy. Senolytics (possibly targeting Cyclin D1), HER2low agents, and AR modulators may overcome resistance in HR+HER2-/Immune-/DRD-, whereas an immune activator beyond checkpoint inhibition is suggested for TN/Immune-/DRD- patients. [1] Wolf et. al., Redefining Breast Cancer Subtypes to Guide Treatment Prioritization and Maximize Response: Predictive Biomarkers across 10 Cancer Therapies. Cancer Cell 2022

Citation Format: Denise M. Wolf, Christina Yau, Julia Wulfkuhle, Rosa I. Gallagher, Lamorna A. Brown Swigart, Gillian L. Hirst, Jean-Philippe Coppe, Mark Jesus M. Magbanua, Rosalyn Sayaman, I-SPY2 Investigators, Laura Sit, Nola M. Hylton, Angela DeMichele, Donald A. Berry, Lajos Pusztai, Douglas Yee, Laura J. Esserman, Emanuel F. Petricoin, Laura Van ’t Veer. PD5-04 Characterizing the HER2-/Immune-/DNA repair (DRD-) response predictive breast cancer subtype: the hunt for new protein targets in a high-needs population with low response to all I-SPY2 agents [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD5-04.

Evaluation of cell-free DNA approaches for multi-cancer early detection

In the Circulating Cell-free Genome Atlas (NCT02889978) substudy 1, we evaluate several approaches for a circulating cell-free DNA (cfDNA)-based multi-cancer early detection (MCED) test by defining clinical limit of detection (LOD) based on circulating tumor allele fraction (cTAF), enabling performance comparisons. Among 10 machine-learning classifiers trained on the same samples and independently validated, when evaluated at 98% specificity, those using whole-genome (WG) methylation, single nucleotide variants with paired white blood cell background removal, and combined scores from classifiers evaluated in this study show the highest cancer signal detection sensitivities. Compared with clinical stage and tumor type, cTAF is a more significant predictor of classifier performance and may more closely reflect tumor biology. Clinical LODs mirror relative sensitivities for all approaches. The WG methylation feature best predicts cancer signal origin. WG methylation is the most promising technology for MCED and informs development of a targeted methylation MCED test.

Consistency of efficacy results across various clinical measures and statistical methods in the lecanemab phase 2 trial of early Alzheimer's disease

BACKGROUND

Lecanemab (BAN2401) is a humanized IgG1 monoclonal antibody that preferentially targets soluble aggregated Aβ species (protofibrils) with activity at insoluble fibrils and slowed clinical decline in an 18-month phase 2 proof-of-concept study (Study 201; ClinicalTrials.gov NCT01767311) in 856 subjects with early Alzheimer's disease (AD). In this trial, subjects were randomized to five lecanemab dose regimens or placebo. The primary efficacy endpoint was change from baseline in the Alzheimer's Disease Composite Score (ADCOMS) at 12 months with Bayesian analyses. The key secondary endpoints were ADCOMS at 18 months and Clinical Dementia Rating-Sum-of-Boxes (CDR-SB) and Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog14) at 18 months. The results have been published previously. Herein, we describe the results of sensitivity analyses evaluating the consistency of the lecanemab efficacy results in Study 201 at the identified dose, the ED90, across multiple statistical methods and multiple endpoints over the duration of the study.

METHODS

The protocol-specified analysis model was a mixed model for repeated measures (MMRM). Sensitivity analyses address the consistency of the conclusions using multiple statistical methods. These include a disease progression model (DPM), a natural cubic spline (NCS) model, a quadratic mixed model (QMM), and 2 MMRMs with additional covariates.

RESULTS

The sensitivity analyses showed positive lecanemab treatment effects for all endpoints and all statistical models considered. The protocol-specified ADCOMS analysis showed a 29.7% slower decline than placebo for ADCOMS at 18 months. The various other analyses of 3 key endpoints showed declines ranging from 26.5 to 55.9%. The results at 12 months are also consistent with those at 18 months.

CONCLUSIONS

The conclusion of the primary analysis of the lecanemab Study 201 is strengthened by the consistently positive conclusions across multiple statistical models, across efficacy endpoints, and over time, despite missing data. The 18-month data from this trial was utilized in the design of the confirmatory phase 3 trial (Clarity AD) and allowed for proper powering for multiple, robust outcomes.

PET-CR as a potential surrogate endpoint in untreated DLBCL: meta-analysis and implications for clinical trial design

This study's focus is the association of end-of-therapy (EOT) PET results with progression-free (PFS) and overall survival (OS) in patients with diffuse large B-cell lymphoma receiving first-line chemoimmunotherapy. We develop a Bayesian hierarchical model for predicting PFS and OS from EOT PET-complete response (PET-CR) using a literature-based meta-analysis of 20 treatment arms and a substudy of 4 treatment arms in 3 clinical trials for which we have patient-level data. The PET-CR rate in our substudy was 72%. The modeled estimates for hazard ratio (PET-CR/non-PET-CR) were 0.13 for PFS (95% CI 0.10, 0.16) and 0.10 for OS (CI 0.07, 0.12). Hazard ratios varied little by patient subtype and were confirmed by the overall meta-analysis. We link these findings to designing future clinical trials and show how our model can be used in adapting the sample size of a trial to accumulating results regarding treatment benefits on PET-CR and a survival endpoint.

Association of hematologic response and assay sensitivity on the prognostic impact of measurable residual disease in acute myeloid leukemia: a systematic review and meta-analysis

Measurable residual disease (MRD) is associated with relapse and survival in acute myeloid leukemia (AML). We aimed to quantify the impact of MRD on outcomes across clinical contexts, including its association with hematologic response and MRD assay sensitivity. We performed systematic literature review and meta-analysis of 48 studies that reported the association between MRD and overall survival (OS) or disease-free survival (DFS) in AML and provided information on the MRD threshold used and the hematologic response of the study population. Among studies limited to patients in complete remission (CR), the estimated 5-year OS for the MRD-negative and MRD-positive groups was 67% (95% Bayesian credible interval [CrI], 53-77%) and 31% (95% CrI, 18-44%), respectively. Achievement of an MRD-negative response was associated with superior DFS and OS, regardless of MRD threshold or analytic sensitivity. Among patients in CR, the benefit of MRD negativity was highest in studies using an MRD cutoff less than 0.1%. The beneficial impact of MRD negativity was observed across MRD assays and timing of MRD assessment. In patients with AML in morphological remission, achievement of MRD negativity is associated with superior DFS and OS, irrespective of hematologic response or the MRD threshold used.

Safety and efficacy of HSP90 inhibitor ganetespib for neoadjuvant treatment of stage II/III breast cancer

HSP90 inhibitors destabilize oncoproteins associated with cell cycle, angiogenesis, RAS-MAPK activity, histone modification, kinases and growth factors. We evaluated the HSP90-inhibitor ganetespib in combination with standard chemotherapy in patients with high-risk early-stage breast cancer. I-SPY2 is a multicenter, phase II adaptively randomized neoadjuvant (NAC) clinical trial enrolling patients with stage II-III breast cancer with tumors 2.5 cm or larger on the basis of hormone receptors (HR), HER2 and Mammaprint status. Multiple novel investigational agents plus standard chemotherapy are evaluated in parallel for the primary endpoint of pathologic complete response (pCR). Patients with HER2-negative breast cancer were eligible for randomization to ganetespib from October 2014 to October 2015. Of 233 women included in the final analysis, 140 were randomized to the standard NAC control; 93 were randomized to receive 150 mg/m2 ganetespib every 3 weeks with weekly paclitaxel over 12 weeks, followed by AC. Arms were balanced for hormone receptor status (51-52% HR-positive). Ganetespib did not graduate in any of the biomarker signatures studied before reaching maximum enrollment. Final estimated pCR rates were 26% vs. 18% HER2-negative, 38% vs. 22% HR-negative/HER2-negative, and 15% vs. 14% HR-positive/HER2-negative for ganetespib vs control, respectively. The predicted probability of success in phase 3 testing was 47% HER2-negative, 72% HR-negative/HER2-negative, and 19% HR-positive/HER2-negative. Ganetespib added to standard therapy is unlikely to yield substantially higher pCR rates in HER2-negative breast cancer compared to standard NAC, and neither HSP90 pathway nor replicative stress expression markers predicted response. HSP90 inhibitors remain of limited clinical interest in breast cancer, potentially in other clinical settings such as HER2-positive disease or in combination with anti-PD1 neoadjuvant chemotherapy in triple negative breast cancer.Trial registration: www.clinicaltrials.gov/ct2/show/NCT01042379.

The Bayesian Time Machine: Accounting for temporal drift in multi-arm platform trials

BACKGROUND

Multi-arm platform trials investigate multiple agents simultaneously, typically with staggered entry and exit of experimental treatment arms versus a shared control arm. In such settings, there is considerable debate whether to limit analyses for a treatment arm to concurrent randomized control subjects or to allow comparisons to both concurrent and non-concurrent (pooled) control subjects. The potential bias from temporal drift over time is at the core of this debate.

METHODS

We propose time-adjusted analyses, including a "Bayesian Time Machine," to model potential temporal drift in the entire study population, such that primary analyses can incorporate all randomized control subjects from the platform trial. We conduct a simulation study to assess performance relative to utilizing concurrent or pooled controls.

RESULTS

In multi-arm platform trials with staggered entry, analyses adjusting for temporal drift (either Bayesian or frequentist) have superior estimation of treatment effects and favorable testing properties compared to analyses using either concurrent or pooled controls. The Bayesian Time Machine generally provides estimates with greater precision and smaller mean square error than alternative approaches, at the risk of small bias and small Type I error inflation.

CONCLUSIONS

The Bayesian Time Machine provides a compromise between bias and precision by smoothing estimates across time and leveraging all available data for the estimation of treatment effects. Prior distributions controlling the behavior of dynamic smoothing across time must be pre-specified and carefully calibrated to the unique context of each trial, appropriately accounting for the population, disease, and endpoints.

Redefining breast cancer subtypes to guide treatment prioritization and maximize response: Predictive biomarkers across 10 cancer therapies

Using pre-treatment gene expression, protein/phosphoprotein, and clinical data from the I-SPY2 neoadjuvant platform trial (NCT01042379), we create alternative breast cancer subtypes incorporating tumor biology beyond clinical hormone receptor (HR) and human epidermal growth factor receptor-2 (HER2) status to better predict drug responses. We assess the predictive performance of mechanism-of-action biomarkers from ∼990 patients treated with 10 regimens targeting diverse biology. We explore >11 subtyping schemas and identify treatment-subtype pairs maximizing the pathologic complete response (pCR) rate over the population. The best performing schemas incorporate Immune, DNA repair, and HER2/Luminal phenotypes. Subsequent treatment allocation increases the overall pCR rate to 63% from 51% using HR/HER2-based treatment selection. pCR gains from reclassification and improved patient selection are highest in HR+ subsets (>15%). As new treatments are introduced, the subtyping schema determines the minimum response needed to show efficacy. This data platform provides an unprecedented resource and supports the usage of response-based subtypes to guide future treatment prioritization.

Precision Promise (PrP): An adaptive, multi-arm registration trial in metastatic pancreatic ductal adenocarcinoma (PDAC)

TPS4188

Background: The success rate of drug development in PDAC is disappointingly low.PrP is a transformative, adaptive platform clinical trial designed to continuously evaluate many novel therapeutic options while increasing the probability that patients (pts) are randomized to effective experimental therapies. It cultivates enhanced cooperation among groups representing pts advocacy, pharmaceutical companies, academia, and the FDA. This patient-centric study aims to become the largest Phase 3 registrational study in PDAC and represents a fundamental shift in drug development for PDAC in the United States (US). Methods: PrP (NCT04229004) is a platform clinical trial sponsored by the Pancreatic Cancer Action Network (PanCAN), developed based on the FDA 2020 guidance document regarding "complex innovative designs" in registration trials https://www.fda.gov/media/130897/download . It utilizes adaptive randomization and other Bayesian statistical innovations provided by Berry Consultants LLC, including the “time machine” which uses all previously randomized controls for each arm, suitably adjusted for line of therapy and the time period of the arm. Focused on 1st and 2nd line treatment of mPDAC, PrP uses an adaptive platform design with randomization to one of 2 control arms (gemcitabine + nab-paclitaxel (GA) or mFOLFIRINOX, 30% of pts) or experimental therapy (70% of pts). Candidate experimental arms are reviewed by an Arm Selection Committee based on validity of the treatment target and strength of the pre-clinical and clinical data. The primary endpoint is overall survival (OS). Pts undergo pre- and on-treatment biopsies with state-of-the-art genomic, transcriptomic, and immune analysis, along with a serial collection of blood-based research samples. Pts are managed using novel supportive care techniques; PrP contains 3 sub-protocols evaluating quality of life, sarcopenia, and actigraphy. PrP launched in 2020 and has enrolled > 130 pts; 30 US sites have been selected with 17 currently active. Current experimental arms include: (i) GA + Pamrevlumab, an anti-CTGF Ab, (ii) Racemetyrosine monotherapy, a cancer metabolism-based therapy (for follow-up of patients) and (iii) an immuno-oncology arm in activation. Other arms are in the planning stages. Compared to traditional designs, PrP offers several advantages: multiple investigational treatments evaluated in parallel over time; ̃175 pts per experimental arm required to initiate a regulatory registration; and continuous learning from every patient, resulting in significant savings of time and resources. PrP has created an entirely new learning environment for accelerating drug development in PDAC. Clinical trial information: NCT04229004.

GBM AGILE: A global, phase 2/3 adaptive platform trial to evaluate multiple regimens in newly diagnosed and recurrent glioblastoma

TPS2078

Background: GBM AGILE (Glioblastoma Adaptive, Global, Innovative Learning Environment) is a biomarker based, multi-arm, international, seamless Phase 2/3 Response Adaptive Randomization platform trial designed to rapidly identify experimental therapies that improve overall survival and confirm efficacious experimental therapies and associated biomarker signatures to support new drug approvals and registration. GBM AGILE is a collaboration between academic investigators, patient organizations and industry to support new drug applications for newly diagnosed and recurrent GBM. With its adaptable structure, GBM AGILE has continued trial activation, inclusion of new investigational therapies, and enrollment globally through the challenges of a global pandemic. Methods: The primary objective of GBM AGILE is to identify therapies that effectively improve the overall survival in patients with ND or recurrent GBM. Bayesian response adaptive randomization is used within subtypes of the disease to assign participants to investigational arms based on their performance. Operating under a Master Protocol, GBM AGILE allows multiple drugs from different pharmaceutical/biotech companies to be evaluated simultaneously and/or over time against a common control. New experimental therapies are added as new information about promising new drugs is identified while other therapies are removed as they complete their evaluation. The master protocol/ trial infrastructure includes efficiencies through an adaptive trial design, shared control arm and operational processes such as risk-based monitoring and enhanced remote activities. GBM AGILE has screened over 1000 patients and enrollment rates are 3 to 4 times greater than traditional GBM trials, with active sites averaging 0.75 to 1 patients/sites/month. While enrollment had an initial dip during the early stages of the pandemic (April-May, 2020), with flexible processes including remote based monitoring, minimizing in person visits, and remote provision of IMP, the enrollment rebounded by June, 2020. Through the use of improved and efficient processes allowed within a master protocol/adaptive platform trial infrastructure, GBM AGILE has been seamlessly operating a global trial during a global pandemic. Clinical trial information: NCT03970447.

Improved pathologic complete response rates for triple-negative breast cancer in the I-SPY2 Trial

591

Background: The I-SPY2 Trial evaluates multiple investigative agents in neoadjuvant breast cancer therapy with the primary endpoint of estimated pathologic complete response (pCR) rate. As a platform phase 2 trial it utilizes an adaptive design to compare new regimens with control chemotherapy (weekly paclitaxel followed by AC). Methods: Specific regimens are assigned based on clinically relevant signatures, including triple negative breast cancer (TNBC). Drug regimens graduate from the trial when the predicted pCR rate in any signature meets the pre-specified threshold of 85% probability of success in a hypothetical 300-patient, 1:1 randomized, phase 3 trial. The strong correlation between pCR rate and event free survival has been reported. To establish the benefit of administering investigational agents in combination with control weekly paclitaxel x 12 in TNBC, we report estimated pCR rates for the first 7 investigational agents. Results: TNBC accounted for 37% (363/987) of enrolled patients. Only veliparib and carboplatin (VC) and pembrolizumab (Pembro) met the graduation criteria for TNBC. However, compared to control chemotherapy, each drug tested in TNBC resulted in a numerically superior pCR rate compared to control. These findings imply that stratification of TNBC by response-predictive biomarkers may lead to improved pCR rates. For example, we have used gene expression profiling to further refine TNBC classification into Immune enhanced (Immune+), Immune-/DNA Repair Deficient (DRD)+, and Immune-/DRD- classes. TNBC identified as immune enhanced (63%) have an 89% pCR rate to pembrolizumab, while VC is less effective with pCR rate of 71%. Similarly, Immune-/DRD+ (11%) identifies TNBCs with a 80% pCR rate to VC, while pembrolizumab’s pCR rate in this group is only 33%. For tumors that are neither immune enhanced or DRD-positive (Immune-/DRD-; 25%) show numerically improved pCR rates for neratinib (20%), MK2206 (25%), ganitumab (24%), and ganetespib (22%) compared to control (12%). pCR rates for VC (10%) and pembrolizumab (20%) in this group were similar to drugs that did not graduate. For TNBC, many agents in I-SPY2 showed numerically improved pCR rates compared to conventional chemotherapy even when they did not meet our specified definition of graduation. Conclusions: Further refinement of TNBC signatures should yield improved therapeutic strategies while also sparing women unnecessary systemic therapy. Clinical trial information: NCT01042379. [Table: see text]

Pathologic complete response (pCR) rates for HR+/HER2- breast cancer by molecular subtype in the I-SPY2 Trial

504

Background: Hormone receptor positive (HR+), HER2- breast cancer (BC) is a heterogenous disease. We hypothesized that molecular subtypes capturing luminal, basal, and immune biology could predict response for patients (pts) with HR+/HER2- disease in the I-SPY2 trial. Methods: I-SPY2 trial is a phase II, randomized, adaptive study evaluating multiple investigational agents as neoadjuvant BC therapy; the primary endpoint is estimated pCR rate. Investigational agents are given with control weekly paclitaxel x 12, followed by AC x 4. Regimens graduate when the predicted pCR rate in any signature meets the pre-specified threshold of 85% probability of success in a hypothetical 300 pt randomized, phase 3 trial. We analyzed estimated pCR rates for the 1st 7 investigational agents in the HR+/HER- subset, analyzed by clinical/molecular features: BluePrint (BP) Luminal vs. Basal, Mammaprint High1 [MP1] vs. Mammaprint High2 [MP2], MP2 is < -0.57, Responsive Predictive Subtype-5 (RPS-5) (classification based on HR, HER2, immune, DNA-repair, and basal/luminal markers), histology, and stage/nodal status. Results: 38% (379/987) of pts had HR+/HER2- disease. Only pembrolizumab met the pre-specified graduation criteria for HR+/HER2- BC. pCR rates by treatment arm and molecular subtype are described in the Table. 28% were MP2; 72% were MP1. Overall, pCR rates were higher in pts with MP2 vs MP1 disease (30% vs 11%) including with pembrolizumab (55% vs. 21%). 29% were BP Basal, 71% were BP Luminal; BP Basal was more likely to be MP2 than BP Luminal (77% vs 8%). In all arms except MK2206, HR+/HER2- BP Basal pts were more likely to achieve pCR than BP Luminal pts. For MK2206, BP Luminal pts were more likely to achieve pCR. Immune+ by RPS-5 (39% of HR+/HER2-) predicted pCR to pembrolizumab irrespective of BP Basal or Luminal status (11 pCR/16 pts). Results by histology and stage/nodal status will also be reported. Conclusions: Our data suggest that MP2 and BP Basal signatures identify a subset of HR+/HER2- BC more likely to respond to neoadjuvant therapy; and that an immune signature can identify pts more likely to respond to pembrolizumab. These findings will aid in guiding prioritization of targeted agents with the goal to optimize pCR for all pts. Clinical trial information: NCT01042379. [Table: see text]

Contributions of screening, early-stage treatment, and metastatic treatment to breast cancer mortality reduction by molecular subtype in U.S. women, 2000-2017

1008

Background: Treatment for metastatic breast cancer has advanced since 2000, but we do not know if those advances have reduced mortality in the general population. Methods: Four Cancer Intervention and Surveillance Network (CISNET) models simulated US breast cancer mortality from 2000 to 2017 using national data on mammography use and performance, efficacy and dissemination of estrogen receptor (ER) and HER2-specific treatments of early-stage (stages I-III) and metastatic (stage IV or distant recurrence) disease, and competing mortality. Models compared overall and ER/HER2-specific breast cancer mortality rates from 2000 to 2017 relative to estimated rates with no screening or treatment, and attributed mortality reductions to screening, early-stage or metastatic treatment. Results of an exemplar model are shown. Results: The mortality reduction attributable to early-stage treatment increased from 35.8% in 2000 to 48.2% in 2017, while the proportion attributable to metastatic treatment decreased slightly from 23.9% to 20.6%. The increasing contribution of early-stage treatment reflects the transition of effective metastatic treatments to early-stage disease: accordingly, ten-year distant recurrence-free survival improved (82.5% in 2000, 87.3% in 2017; for ER+HER2+, 78.2% to 90.9%). Survival time after metastatic diagnosis also increased, doubling from 1.48 years in 2000 to 2.80 years in 2017, with the best survival for women with ER+HER2+ cancers (4.08 years) and worst for ER-HER2- (1.22 years). Conclusions: Advances in metastatic breast cancer treatment are reflected in lower population mortality, both through transition to early-stage treatment and gains for women with metastatic disease. These results may inform patient/physician discussions about breast cancer prognosis and expected benefits of treatment. [Table: see text]

Matched external control analysis of event-free survival (EFS) in patients with high-risk neuroblastoma (HRNB) receiving eflornithine (DFMO) maintenance

10010

Background: Long term survival in HRNB patients remains a challenge with relapse as the primary cause of mortality. DFMO has been evaluated as a chemopreventative therapy in a single arm study designed to compare EFS outcomes with published rates for the Phase 3 Children’s Oncology Group ch14.18 immunotherapy trial, ANBL0032. In order to address the limitations associated with comparison to a historical control group, we used ANBL0032 patient-level data and propensity-score matching (PSM) to simulate a randomized study comparing EFS of patients treated with DFMO after ch14.18 (treated) to ANBL0032 patients who did not subsequently receive DFMO (control). Methods: A phase 2 trial enrolled a total of 140 HRNB patients in remission at the completion of disease treatment from 2012 to 2016. Patients received 2 years of continuous treatment with DFMO 750 ±250 mg/m2 BID and were followed for up to 7 years. ANBL0032 enrolled a total of 1328 HRNB patients from 2001 to 2015 who were assigned to treatment with ch14.18 immunotherapy and followed for up to 10 years. With FDA input, we defined selection rules to identify like groups of treated and control patients eligible for matching, covariates of potential prognostic importance, and matching algorithm details. PSM was used to balance cohorts on their baseline demographic and characteristics, matching each treated patient with the 3 most closely scored control patients with an exact match on MYCN. The Kaplan-Meier method and Cox regression analyses were used to compare EFS (primary) and overall survival (OS) (key secondary) endpoints. Multiple sensitivity analyses were performed to further investigate the primary comparison. Results: A total of 92 treated patients and 852 control patients met selection criteria, with 91 and 516, respectively, having complete covariate data required for the analysis. Eighty-seven (94.6%) of the treated group had verified participation in ANBL0032 immediately prior to enrollment in the DFMO trial. EFS from end of immunotherapy was significantly improved in the matched DFMO group (n=90) vs. control group (n=270), with a hazard ratio of 0.48 (95% CI: 0.27, 0.85) and a p-value of 0.0114. Four-year EFS was 84.4% (95% CI 75.2, 90.5) in the DFMO group versus 72.8% (95% CI 67.0, 77.7) in the control group. OS rates were also higher for DFMO group in the matched population, with a hazard ratio of 0.36 (95% CI: 0.16, 0.79) and a p-value of 0.0105. EFS sensitivity analyses demonstrated consistent results, including those challenging selection criteria for the control population. Conclusions: Patients in remission after standard upfront therapy treated with DFMO had approximately half the risk of relapse compared to matched control patients. The PSM comparisons represent the most statistically robust findings to date supporting the benefit of DFMO as a maintenance treatment for HRNB. Clinical trial information: NCT02395666, NCT00026312.

Molecular subtype to predict pathologic complete response in HER2-positive breast cancer in the I-SPY2 trial

510

Background: HER2-positive breast cancer (bc) is a very heterogenous disease. We hypothesized that molecular subtype may predict disease response to investigational agents in HER2+ bc. Here, we report the pathologic complete response (pCR) rate in the first six agents tested in HER2+ bc in the I-SPY 2 trial for the full HER2+ cohort, by molecular subtype, and by disease receptor status. Methods: Women with HER2+ tumors which were > 2.5 cm were eligible. The I-SPY2 platform trial tests novel agents given neoadjuvantly with a backbone of taxol (T) and trastuzumab (H) followed by doxorubicin and cyclophosphamide. Agents investigated in HER2+ bc were TH (control), MK2206, AMG386, pertuzumab (P), neratinib (N (given in place of H), and TDM1+P (given in place of TH). An investigational arm graduated if there was >85% chance of success compared to control in a 300-person phase 3 neoadjuvant trial. Further details of the I-SPY2 methods have been previously published. Molecular subtyping based on gene expression was utilized to categorize tumors into 5 response predictive subtypes (RPS) (HER2-/Immune-/DRD (DNA repair deficiency)-, HER2-/Immune+, HER2-/Immune-/DRD+, HER2+/Her2_or_Basal and HER2+/Luminal). Results: For the full HER2+ cohort (N=245) pCR rate was higher in all investigational arms than control (Table). By tumor receptor status, HER2+/HR- tumors (N=89) had a higher pCR rate than HER2+/HR+ tumors (N=156; 63% vs 37%, p = 0.0001). In HER2+/HR- tumors N, MK2206, P and TDM1/P graduated. In HER2+/HR+ tumors P and TDM1/P graduated. 76% (185/245) of I-SPY 2 HER2+ patients were classified as HER2+/Her2_or_Basal and 24% (60/245) were HER2+Luminal. pCR rate was significantly higher in the HER2+/Her2_or_Basal group than in the HER2+/Luminal group (57% vs 15%, p < 0.0001). All agents, except for MK2206, where numbers were small, showed greater efficacy in the HER2+/Her2_or_Basal group than in the HER2+/Luminal group. HER2+/Luminal appeared to be more sensitive to the AKT inhibitor MK2206 than to targeted HER2 agents, though numbers are small. Conclusions: pCR rates for patients with HER2+ bc treated with investigational agents, particularly dual HER2-blockade, were promising. Molecular response predictive subtype classification provides insight on how to better target therapy. The HER2+/Luminal group had low pCR rates with dual HER2-blockade but may have higher pCR rate with the addition of an AKT inhibitor and identifies a subgroup of HER2+ tumors in need of novel approaches. AKT inhibition for HER2/Luminal is being tested in I-SPY 2.2. Clinical trial information: NCT01042379. [Table: see text]

Distribution of breast cancer molecular subtypes within receptor classifications: Lessons from the I-SPY2 Trial and FLEX Registry

592

Background: Expression-based molecular subtypes of breast cancer (BC) predict tumor behavior and therapeutic response. Subtype distributions by age and sociodemographics can inform strategies for BC screening, treatment, and prognosis. The conventional approach, adopted by NCI’s Surveillance, Epidemiology, and End Results (SEER) Program, uses HR and HER2 to label: “triple negative” (HR-HER2-), “HER2-enriched” (HR-HER2+), “luminal A” (HR+HER2-), and “luminal B” (HR+HER2+). However, immunohistochemical (IHC)-based receptor labels may not reflect clinically and epidemiologically relevant molecular subtypes that share the same nomenclature, e.g., luminal B. Methods: We compared IHC labels by HR/HER2 to molecular subtypes by MammaPrint (MP) and BluePrint (BP) for patients in the phase II neoadjuvant I-SPY2 TRIAL for high-risk, stage II-III BC (NCT01042379, n = 981) and in the multicenter, prospective FLEX Registry for stage I-III BC (NCT03053193, n = 5,679). Results: IHC labels were discordant with MP/BP in 52% of I-SPY2 and 43% of FLEX cases (Table 1). HR-HER2- had the highest concordance with basal-type (99% in I-SPY2, 88% in FLEX). HR+ labels had the least agreement with MP/BP: HR+HER2- tumors were molecularly luminal B and basal in 71% and 29% of I-SPY2 and 40% and 4% of FLEX cases, respectively. HR+HER2+ tumors were molecularly luminal A and HER2-type in 10% and 60% of I-SPY2 and 15% and 36% of FLEX cases, respectively. Of molecularly luminal B cases, only 14% in I-SPY2 and 7% in FLEX were HR+HER2+. Conclusions: IHC markers collected by population-based registries (SEER) enable BC surveillance. However, IHC labels cannot be used as surrogates for molecular subtypes by MP/BP, especially for luminal B tumors. Given the unmet need to improve management of luminal B BC, we anticipate the growing importance of molecular subtyping to inform treatment and epidemiological research. We propose that the BC research community work with SEER to update its IHC labels to avoid overlap with molecular subtype nomenclature and incorporate such modern classifications when available. [Table: see text]

Abstract PD4-02: Safety and efficacy of a tucatinib-trastuzumab-capecitabine regimen for treatment of leptomeningeal metastasis (LM) in HER2-positive breast cancer: Results from TBCRC049, a phase 2 non-randomized study

Background: Treatment options for patients (pts) with leptomeningeal metastasis (LM) are limited, and the prognosis is poor (median overall survival (OS) ~ 4-5 months). Tucatinib is a potent and highly selective HER2-targeted tyrosine kinase inhibitor approved for use in combination with trastuzumab and capecitabine in pts with metastatic HER2+ breast cancer who have received ≥1 prior HER2-based regimen in the metastatic setting, including pts with brain metastases. TBCRC049 (NCT03501979) is an investigator-initiated, phase 2, single-arm study evaluating the safety and efficacy of tucatinib, trastuzumab and capecitabine in HER2+ breast cancer with newly diagnosed LM. We have previously demonstrated therapeutic levels of tucatinib in CSF in pts with HER2+ LM (Stringer-Reasor et al, ASCO 2021). We now report efficacy outcomes of the study. Methods: Eligible pts were adults with HER2+ metastatic breast cancer, Karnofsky performance status (KPS) &gt; 50, and newly diagnosed, untreated LM (defined as positive CSF cytology and/or radiographic evidence of LM, plus clinical signs/symptoms). Pts with treated or concurrent/new brain metastases were allowed. Pts received tucatinib 300 mg orally twice daily starting with cycle 1, day 1 (C1D1); capecitabine 1000 mg/m2 orally twice daily on days 1-14 of a 21-day cycle, starting on C1D1; and trastuzumab loading dose of 8 mg/kg IV on C1D1, and then 6 mg/kg IV once every 21 days, starting with C2D1. The primary endpoint was OS. Planned enrollment was 30 pts; however, due to lack of accrual since the FDA approval of tucatinib (4/2020), the study was closed after 17 patients were enrolled. Results: Baseline disease characteristics at LM diagnosis are shown in Table 1. Eight pts (47%) had abnormal CSF cytology (positive or equivocal). All pts had MRI evidence of LM in the brain, and 14/17 (82%) had brain metastases, of which 11 (65%) had received prior treatment for brain metastases. Median age at study treatment initiation was 53 years. Median number of treatment cycles received was 5 (range: 2-27). Median OS time was 11.9 months (95% CI: 4.1, NR). At data cutoff (6/22/21), 7/17 pts (41%) remained alive and median followup was 17 months(8-26). Median time to CNS progression was 6.9 months (95% CI: 2.8, 13.8). Conclusions: In pts with LMD from HER2+ metastatic breast cancer who were treated with tucatinib, trastuzumab, and capecitabine, the median OS time was nearly 1 year. This is the first prospective evidence of clinical benefit with a systemic regimen for HER2+ LM. Further studies evaluating brain-penetrant oral drugs in this rare pt population are needed.

Baseline Disease Characteristics (N=17)Number%Baseline CSF cytologyPositive529%Negative847%Equivocal318%None obtained1*6%Symptoms attributable to LMDYes1588%No212%MRI evidence of LMDBrain only1165%Brain and Spine635%History of brain metastasisYes1482%Prior treatment1165%New/concurrent diagnosis – no prior treatment318%No318%Extra-CNS DiseaseYes1165%No635%*One patient had VP shunt and difficulty sampling fluid; all CSF sent for research PK and non-PK studies

Citation Format: Rashmi K Murthy, Barbara O'Brien, Donald A Berry, Akshara Singareeka-Raghavendra, Maria Gule Monroe, Jason Johnson, Jason White, Jennifer Childress, Justin Sanford, Jill Schwartz-Gomez, Michelle Melisko, Aki Morikawa, Sherise Ferguson, John F de Groot, Ian Krop, Vicente Valero, Mothaffar Rimawi, Antonio Wolff, Debu Tripathy, Nancy U Lin, Erica Stringer-Reasor. Safety and efficacy of a tucatinib-trastuzumab-capecitabine regimen for treatment of leptomeningeal metastasis (LM) in HER2-positive breast cancer: Results from TBCRC049, a phase 2 non-randomized study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD4-02.

Abstract PD8-07: Evaluation of Tucatinib + (Paclitaxel + Pertuzumab + Trastuzumab) followed by AC in high-risk HER2 positive (HER2+) stage II/III breast cancer: Results from the I-SPY 2 TRIAL

Background: I-SPY 2 is a multicenter, phase 2 trial using response-adaptive randomization within molecular subtypes defined by receptor status and MammaPrint (MP) risk to evaluate novel agents as neoadjuvant therapy for women with high-risk breast cancer. Tucatinib is a potent HER2 (ErbB2) tyrosine kinase inhibitor, selective for HER2 vs. epidermal growth factor receptor (EGFR) and is active vs. brain metastases. Safety and efficacy of tucatinib combined with paclitaxel, pertuzumab, and trastuzumab are unknown and were tested in a planned 10 patient (pt) safety run-in of the I-SPY 2 trial. Methods: Women with tumors ≥ 2.5cm were eligible for screening. Only pts with tumors that were HER2+ by FISH were eligible for this treatment. Treatment included tucatinib (max dose 300 mg) BID for 12 weeks with weekly paclitaxel 80 mg/m2 and trastuzumab (2 mg/kg weekly following loading), and pertuzumab (420 mg every 3 weeks following loading), followed by doxorubicin/cyclophosphamide (AC) every 2 weeks x 4. The control arm was weekly paclitaxel and trastuzumab with pertuzumab for 12 weeks followed by AC every 2 weeks x 4. All pts undergo serial MR imaging and response at 3 & 12 weeks is combined with real time pCR data to estimate, and continuously update, the predicted pCR rate for each trial arm. The goal of the trial is to identify/graduate regimens with ≥85.% Bayesian predictive probability of success (i.e. demonstrating superiority to control) in a future 300-patient phase 3 neoadjuvant trial with a pCR endpoint. This run-in arm was conducted to determine safety of combining tucatinib with paclitaxel/trastuzumab/pertuzumab, monitoring special adverse events of interest including LFT elevations and gastrointestinal toxicities.Methods: The I-SPY 2 methods have been previously published. Results: 20 pts were evaluable in tucatinib treatment arm. The control arm included 329 historical controls enrolled since April 2010. The initial tucatinib dose was 300 mg BID. After enrollment of the first 8 pts, there were 3 pts with grade 3 LFT elevations, 2 pts with grade 2/3 diarrhea, 1 pt with grade 2 neutropenia, and 1 pt with grade 3 nausea. After this safety review, the tucatinib dose was lowered to 250 mg BID. Among 5 additional pts enrolled, 3 developed grade 2/3 LFT abnormalities. The protocol was then modified to tucatinib 150 mg BID days 1-28 and then 250 mg BID days 29-84; 7 pts were treated. Safety data were reviewed after 20 pts were enrolled; the arm was then suspended due to similar LFT elevations regardless of tucatinib dose reduction or schedule. 7 of 20 pts (35%) had reversible Grade 3 or higher ALT/AST elevation (Table). No pt met criteria for Hy’s Law. In terms of efficacy, 12 of 14 evaluable pts had &gt; 80% reduction of tumor volume by 12 weeks, measured by MRI assessment of functional tumor volume (FTV). Conclusion: The goal of the run-in arm was to determine the safety of adding tucatinib to the combination of paclitaxel/trastuzumab/pertuzumab. The addition of tucatinib resulted in unacceptable but reversible LFT elevations despite tucatinib dose reduction. Tucatinib containing therapy resulted in &gt;80% decline in tumor volume at 12 weeks in 86% of pts. Tucatinib showed a high level of activity when combined with paclitaxel/trastuzumab/pertuzumab, but the combination is not feasible. Table: Number of pts with grade 2, 3, and 4 LFT elevations by treatment schedule (highest grade per patient per event, ALT or

Treatment scheduleGrade 2 LFT elevationGrade 3 LFT elevationGrade 4 LFT elevationTucatinib 300 mg BID030Tucatinib 250 mg BID210Tucatinib 150 mg BID days 1-28 followed by 250 mg BID days 29 to 84112

Citation Format: David A Potter, Erin Roesch, Christina Yau, Ruixiao Lu, Denise Wolf, Susan Samson, Debra Stafford, Kathy S Albain, Claudine Isaacs, Meghana Trivedi, Douglas Yee, Judy Boughey, Alexandra Thomas, A. Jo Chien, Nola Hylton, Wen Li, Angela DeMichele, Jane Perlmutter, W. Fraser Symmans, Dawn L Hershman, Michelle Melisko, Laura J van 't Veer, Amy Wilson, Smita M Asare, Donald A Berry, Richard Schwab, Hope S Rugo, Laura J Esserman. Evaluation of Tucatinib + (Paclitaxel + Pertuzumab + Trastuzumab) followed by AC in high-risk HER2 positive (HER2+) stage II/III breast cancer: Results from the I-SPY 2 TRIAL [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD8-07.

Designing Clinical Trials for Combination Immunotherapy: A Framework for Glioblastoma

Immunotherapy has revolutionized treatment for many hard-to-treat cancers but has yet to produce significant improvement in outcomes for patients with glioblastoma. This reflects the multiple and unique mechanisms of immune evasion and escape in this highly heterogeneous tumor. Glioblastoma engenders profound local and systemic immunosuppression and is remarkably effective at inducing T-cell dysfunction, posing a challenge to any immunotherapy-based approach. To overcome these mechanisms, multiple disparate modes of immune-oriented therapy will be required. However, designing trials that can evaluate these combinatorial approaches requires careful consideration. In this review, we explore the immunotherapy resistance mechanisms that have been encountered to date and how combinatorial approaches may address these. We also describe the unique aspects of trial design in both preclinical and clinical settings and consider endpoints and markers of response best suited for an intervention involving multiple agents.

A Randomized Placebo-Controlled Phase 3 Study of Mesenchymal stem cells induced to secrete high levels of neurotrophic factors in Amyotrophic Lateral Sclerosis

Introduction/Aims

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative illness with great unmet patient need. We aimed to evaluate whether mesenchymal stem cells induced to secrete high levels of neurotrophic factors (MSC‐NTF), a novel autologous cell‐therapy capable of targeting multiple pathways, could safely slow ALS disease progression.

Methods

This randomized, double‐blind, placebo‐controlled study enrolled ALS participants meeting revised El Escorial criteria, revised ALS Functional Rating Scale (ALSFRS‐R) ≥25 (screening) and ≥3 ALSFRS‐R points decline prior to randomization. Participants received three treatments of MSC‐NTF or placebo intrathecally. The primary endpoint evaluated efficacy of MSC‐NTF through a responder analysis and safety. A change in disease progression post‐treatment of ≥1.25 points/mo defines a clinical response. A pre‐specified analysis leveraged baseline ALSFRS‐R of 35 as a subgroup threshold.

Results

Overall, MSC‐NTF treatment was well tolerated; there were no safety concerns. Thirty‐three percent of MSC‐NTF and 28% of placebo participants met clinical response criteria at 28 wk (odds ratio [OR] = 1.33, P = .45); thus, the primary endpoint was not met. A pre‐specified analysis of participants with baseline ALSFRS‐R ≥ 35 (n = 58) showed a clinical response rate at 28 wk of 35% MSC‐NTF and 16% placebo (OR = 2.6, P = .29). Significant improvements in cerebrospinal biomarkers of neuroinflammation, neurodegeneration, and neurotrophic factor support were observed with MSC‐NTF, with placebo unchanged.

Discussion

The study did not reach statistical significance on the primary endpoint. However, a pre‐specified subgroup suggests that MSC‐NTF participants with less severe disease may have retained more function compared to placebo. Given the unmet patient need, the results of this trial warrant further investigation.

Neoadjuvant T-DM1/pertuzumab and paclitaxel/trastuzumab/pertuzumab for HER2+ breast cancer in the adaptively randomized I-SPY2 trial

HER2-targeted therapy dramatically improves outcomes in early breast cancer. Here we report the results of two HER2-targeted combinations in the neoadjuvant I-SPY2 phase 2 adaptive platform trial for early breast cancer at high risk of recurrence: ado-trastuzumab emtansine plus pertuzumab (T-DM1/P) and paclitaxel, trastuzumab and pertuzumab (THP). Eligible women have >2.5 cm clinical stage II/III HER2+ breast cancer, adaptively randomized to T-DM1/P, THP, or a common control arm of paclitaxel/trastuzumab (TH), followed by doxorubicin/cyclophosphamide, then surgery. Both T-DM1/P and THP arms 'graduate' in all subtypes: predicted pCR rates are 63%, 72% and 33% for T-DM1/P (n = 52), THP (n = 45) and TH (n = 31) respectively. Toxicity burden is similar between arms. Degree of HER2 pathway signaling and phosphorylation in pretreatment biopsy specimens are associated with response to both T-DM1/P and THP and can further identify highly responsive HER2+ tumors to HER2-directed therapy. This may help identify patients who can safely de-escalate cytotoxic chemotherapy without compromising excellent outcome.

Breast MRI during Neoadjuvant Chemotherapy: Lack of Background Parenchymal Enhancement Suppression and Inferior Treatment Response

Background Suppression of background parenchymal enhancement (BPE) is commonly observed after neoadjuvant chemotherapy (NAC) at contrast-enhanced breast MRI. It was hypothesized that nonsuppressed BPE may be associated with inferior response to NAC. Purpose To investigate the relationship between lack of BPE suppression and pathologic response. Materials and Methods A retrospective review was performed for women with menopausal status data who were treated for breast cancer by one of 10 drug arms (standard NAC with or without experimental agents) between May 2010 and November 2016 in the Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging and Molecular Analysis 2, or I-SPY 2 TRIAL (NCT01042379). Patients underwent MRI at four points: before treatment (T0), early treatment (T1), interregimen (T2), and before surgery (T3). BPE was quantitatively measured by using automated fibroglandular tissue segmentation. To test the hypothesis effectively, a subset of examinations with BPE with high-quality segmentation was selected. BPE change from T0 was defined as suppressed or nonsuppressed for each point. The Fisher exact test and the Z tests of proportions with Yates continuity correction were used to examine the relationship between BPE suppression and pathologic complete response (pCR) in hormone receptor (HR)-positive and HR-negative cohorts. Results A total of 3528 MRI scans from 882 patients (mean age, 48 years ± 10 [standard deviation]) were reviewed and the subset of patients with high-quality BPE segmentation was determined (T1, 433 patients; T2, 396 patients; T3, 380 patients). In the HR-positive cohort, an association between lack of BPE suppression and lower pCR rate was detected at T2 (nonsuppressed vs suppressed, 11.8% [six of 51] vs 28.9% [50 of 173]; difference, 17.1% [95% CI: 4.7, 29.5]; P = .02) and T3 (nonsuppressed vs suppressed, 5.3% [two of 38] vs 27.4% [48 of 175]; difference, 22.2% [95% CI: 10.9, 33.5]; P = .003). In the HR-negative cohort, patients with nonsuppressed BPE had lower estimated pCR rate at all points, but the P values for the association were all greater than .05. Conclusions In hormone receptor-positive breast cancer, lack of background parenchymal enhancement suppression may indicate inferior treatment response. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Philpotts in this issue.

Assessment of Residual Cancer Burden and Event-Free Survival in Neoadjuvant Treatment for High-risk Breast Cancer: An Analysis of Data From the I-SPY2 Randomized Clinical Trial

Importance

Residual cancer burden (RCB) distributions may improve the interpretation of efficacy in neoadjuvant breast cancer trials.

Objective

To compare RCB distributions between randomized control and investigational treatments within subtypes of breast cancer and explore the relationship with survival.

Design, Setting, and Participants

The I-SPY2 is a multicenter, platform adaptive, randomized clinical trial in the US that compares, by subtype, investigational agents in combination with chemotherapy vs chemotherapy alone in adult women with stage 2/3 breast cancer at high risk of early recurrence. Investigational treatments graduated in a prespecified subtype if there was 85% or greater predicted probability of higher rate of pathologic complete response (pCR) in a confirmatory, 300-patient, 1:1 randomized, neoadjuvant trial in that subtype. Evaluation of a secondary end point was reported from the 10 investigational agents tested in the I-SPY2 trial from March 200 through 2016, and analyzed as of September 9, 2020. The analysis plan included modeling of RCB within subtypes defined by hormone receptor (HR) and ERBB2 status and compared control treatments with investigational treatments that graduated and those that did not graduate.

Interventions

Neoadjuvant paclitaxel plus/minus 1 of several investigational agents for 12 weeks, then 12 weeks of cyclophosphamide/doxorubicin chemotherapy followed by surgery.

Main Outcomes and Measures

Residual cancer burden (pathological measure of residual disease) and event-free survival (EFS).

Results

A total of 938 women (mean [SD] age, 49 [11] years; 66 [7%] Asian, 103 [11%] Black, and 750 [80%] White individuals) from the first 10 investigational agents were included, with a median follow-up of 52 months (IQR, 29 months). Event-free survival worsened significantly per unit of RCB in every subtype of breast cancer (HR-positive/ERBB2-negative: hazard ratio [HZR], 1.75; 95% CI, 1.45-2.16; HR-positive/ERBB2-positive: HZR, 1.55; 95% CI, 1.18-2.05; HR-negative/ERBB2-positive: HZR, 2.39; 95% CI, 1.64-3.49; HR-negative/ERBB2-negative: HZR, 1.99; 95% CI, 1.71-2.31). Prognostic information from RCB was similar from treatments that graduated (HZR, 2.00; 95% CI, 1.57-2.55; 254 [27%]), did not graduate (HZR, 1.87; 95% CI, 1.61-2.17; 486 [52%]), or were control (HZR, 1.79; 95% CI, 1.42-2.26; 198 [21%]). Investigational treatments significantly lowered RCB in HR-negative/ERBB2-negative (graduated and nongraduated treatments) and ERBB2-positive subtypes (graduated treatments), with improved EFS (HZR, 0.61; 95% CI, 0.41-0.93) in the exploratory analysis.

Conclusions and Relevance

In this randomized clinical trial, the prognostic significance of RCB was consistent regardless of subtype and treatment. Effective neoadjuvant treatments shifted the distribution of RCB in addition to increasing pCR rate and appeared to improve EFS. Using a standardized quantitative method to measure response advances the interpretation of efficacy.

Trial Registration

ClinicalTrials.gov Identifier: NCT01042379.

Ganitumab and metformin plus standard neoadjuvant therapy in stage 2/3 breast cancer

I-SPY2 is an adaptively randomized phase 2 clinical trial evaluating novel agents in combination with standard-of-care paclitaxel followed by doxorubicin and cyclophosphamide in the neoadjuvant treatment of breast cancer. Ganitumab is a monoclonal antibody designed to bind and inhibit function of the type I insulin-like growth factor receptor (IGF-1R). Ganitumab was tested in combination with metformin and paclitaxel (PGM) followed by AC compared to standard-of-care alone. While pathologic complete response (pCR) rates were numerically higher in the PGM treatment arm for hormone receptor-negative, HER2-negative breast cancer (32% versus 21%), this small increase did not meet I-SPY's prespecified threshold for graduation. PGM was associated with increased hyperglycemia and elevated hemoglobin A1c (HbA1c), despite the use of metformin in combination with ganitumab. We evaluated several putative predictive biomarkers of ganitumab response (e.g., IGF-1 ligand score, IGF-1R signature, IGFBP5 expression, baseline HbA1c). None were specific predictors of response to PGM, although several signatures were associated with pCR in both arms. Any further development of anti-IGF-1R therapy will require better control of anti-IGF-1R drug-induced hyperglycemia and the development of more predictive biomarkers.

Hypothermia for Patients Requiring Evacuation of Subdural Hematoma: A Multicenter Randomized Clinical Trial

Background

Hypothermia is neuroprotective in some ischemia–reperfusion injuries. Ischemia–reperfusion injury may occur with traumatic subdural hematoma (SDH). This study aimed to determine whether early induction and maintenance of hypothermia in patients with acute SDH would lead to decreased ischemia–reperfusion injury and improve global neurologic outcome.

Methods

This international, multicenter randomized controlled trial enrolled adult patients with SDH requiring evacuation of hematoma within 6 h of injury. The intervention was controlled temperature management of hypothermia to 35 °C prior to dura opening followed by 33 °C for 48 h compared with normothermia (37 °C). Investigators randomly assigned patients at a 1:1 ratio between hypothermia and normothermia. Blinded evaluators assessed outcome using a 6-month Glasgow Outcome Scale Extended score. Investigators measured circulating glial fibrillary acidic protein and ubiquitin C-terminal hydrolase L1 levels.

Results

Independent statisticians performed an interim analysis of 31 patients to assess the predictive probability of success and the Data and Safety Monitoring Board recommended the early termination of the study because of futility. Thirty-two patients, 16 per arm, were analyzed. Favorable 6-month Glasgow Outcome Scale Extended outcomes were not statistically significantly different between hypothermia vs. normothermia groups (6 of 16, 38% vs. 4 of 16, 25%; odds ratio 1.8 [95% confidence interval 0.39 to ∞], p = .35). Plasma levels of glial fibrillary acidic protein (p = .036), but not ubiquitin C-terminal hydrolase L1 (p = .26), were lower in the patients with favorable outcome compared with those with unfavorable outcome, but differences were not identified by temperature group. Adverse events were similar between groups.

Conclusions

This trial of hypothermia after acute SDH evacuation was terminated because of a low predictive probability of meeting the study objectives. There was no statistically significant difference in functional outcome identified between temperature groups.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-021-01334-w.

Development and validation of a prognostic 40-day mortality risk model among hospitalized patients with COVID-19

Objectives

The development of a prognostic mortality risk model for hospitalized COVID-19 patients may facilitate patient treatment planning, comparisons of therapeutic strategies, and public health preparations.

Methods

We retrospectively reviewed the electronic health records of patients hospitalized within a 13-hospital New Jersey USA network between March 1, 2020 and April 22, 2020 with positive polymerase chain reaction results for SARS-CoV-2, with follow-up through May 29, 2020. With death or hospital discharge by day 40 as the primary endpoint, we used univariate followed by stepwise multivariate proportional hazard models to develop a risk score on one-half the data set, validated on the remainder, and converted the risk score into a patient-level predictive probability of 40-day mortality based on the combined dataset.

Results

The study population consisted of 3123 hospitalized COVID-19 patients; median age 63 years; 60% were men; 42% had >3 coexisting conditions. 713 (23%) patients died within 40 days of hospitalization for COVID-19. From 22 potential candidate factors 6 were found to be independent predictors of mortality and were included in the risk score model: age, respiratory rate ≥25/minute upon hospital presentation, oxygenation <94% on hospital presentation, and pre-hospital comorbidities of hypertension, coronary artery disease, or chronic renal disease. The risk score was highly prognostic of mortality in a training set and confirmatory set yielding in the combined dataset a hazard ratio of 1.80 (95% CI, 1.72, 1.87) for one unit increases. Using observed mortality within 20 equally sized bins of risk scores, a predictive model for an individual’s 40-day risk of mortality was generated as -14.258 + 13.460*RS + 1.585*(RS–2.524)^2–0.403*(RS–2.524)^3. An online calculator of this 40-day COVID-19 mortality risk score is available at www.HackensackMeridianHealth.org/CovidRS.

Conclusions

A risk score using six variables is able to prognosticate mortality within 40-days of hospitalization for COVID-19.

Trial registration

Clinicaltrials.gov Identifier: NCT04347993.

Durvalumab with olaparib and paclitaxel for high-risk HER2-negative stage II/III breast cancer: Results from the adaptively randomized I-SPY2 trial

The combination of PD-L1 inhibitor durvalumab and PARP inhibitor olaparib added to standard paclitaxel neoadjuvant chemotherapy (durvalumab/olaparib/paclitaxel [DOP]) was investigated in the phase II I-SPY2 trial of stage II/III HER2-negative breast cancer. Seventy-three participants were randomized to DOP and 299 to standard of care (paclitaxel) control. DOP increased pathologic complete response (pCR) rates in all HER2-negative (20%-37%), hormone receptor (HR)-positive/HER2-negative (14%-28%), and triple-negative breast cancer (TNBC) (27%-47%). In HR-positive/HER2-negative cancers, MammaPrint ultra-high (MP2) cases benefited selectively from DOP (pCR 64% versus 22%), no benefit was seen in MP1 cancers (pCR 9% versus 10%). Overall, 12.3% of patients in the DOP arm experienced immune-related grade 3 adverse events versus 1.3% in control. Gene expression signatures associated with immune response were positively associated with pCR in both arms, while a mast cell signature was associated with non-pCR. DOP has superior efficacy over standard neoadjuvant chemotherapy in HER2-negative breast cancer, particularly in a highly sensitive subset of high-risk HR-positive/HER2-negative patients.

Stereotactic ablative radiotherapy in operable stage I NSCLC patients: Long-term results of the expanded STARS clinical trial

8506

Background: We published a pooled analysis of 2 randomized trials (STARS/ROSEL) that compared lobectomy with mediastinal lymph node dissection (L-MLND) vs stereotactic ablative radiotherapy (SABR) in operable stage I NSCLC. There were no significant differences in disease progression but significantly higher 3-year overall survival (OS) in the SABR arm (95% vs 79%). Owing to concerns regarding the small sample size (n = 58), short follow-up (3 years), and non-uniform use of video-assisted thoracoscopic surgery (VATS), we expanded the STARS protocol to a single-arm SABR trial with a protocol-specified comparison to a published, longitudinally-followed institutional cohort of stage IA NSCLC status post VATS L-MLND (n = 229). Methods: Inclusion criteria were stage IA NSCLC (≤3 cm, N0M0 and staged by PET/CT with EBUS) with Zubrod performance status (PS) 0-2, baseline FEV1 > 40% and DLCO > 40% and deemed operable by a multidisciplinary team. SABR utilized 4-dimensional CT simulation and volumetric image guidance; 54 Gy in 3 fractions were delivered to planning target volumes (PTVs) located peripherally, or 50 Gy in 4 fractions to more central PTVs. All patients were followed by chest CT every three months for the first two years, every 6 months for another three years, and then annually. Non-inferiority of SABR could be claimed if the 3-year OS was not lower than the historical VATS L-MLND cohort by more than 12%. We conducted a risk-factor matched comparison study of the primary outcome between the SABR and the historical VATS L-MLND. Results: The median follow-up among the 80 SABR patients was 61 months (range, 34-79 months). The OS and progression-free survival (PFS) were 91% (95% CI: 85̃98%) and 80% (95% CI: 72̃89%) at 3 years, and 87% (95% CI: 79̃95%) and 77% (95% CI: 68̃87%) at 5 years, respectively. The 5-year cumulative incidence rate counting death as competing risk was 6.3% (95% CI: 2.3̃13.2%) local, 12.5% (95% CI: 6.4̃20.8%) regional, and 8.8% (95% CI: 3.8̃16.2%) distant (any recurrence 17.6% (95% CI: 10.1̃26.7%)). The 5 year cumulative incidence rate of second lung primary was 6.9% (95% CI: 2.5̃14.6%). There were 1.3% grade 3 and no grade 4-5 toxicities. The propensity score matched (age, gender, tumor size, histology, PS) comparison of SABR vs VATS L-MLND revealed no significant differences in PFS (p = 0.063), lung cancer-specific survival (p = 0.075), or cumulative incidence rates of local (p = 0.54), regional (p = 0.97), or distant failures (p = 0.33). The SABR arm was associated with significantly higher OS (91% vs 82% at 3 years and 87% vs 72% at 5 years; p = 0.012 from log-rank test). The hazard ratio was 0.411 (95% CI: 0.193̃0.875; p = 0.021). Conclusions: The long-term OS and PFS of SABR is not inferior to VATS L-MLND for operable stage IA NSCLC. SABR remains a promising approach for this population, but multidisciplinary management is strongly recommended. Clinical trial information: NCT02357992.

Evaluation of intra-tumoral (IT) SD-101 and pembrolizumab (Pb) in combination with paclitaxel (P) followed by AC in high-risk HER2-negative (HER2-) stage II/III breast cancer: Results from the I-SPY 2 trial

508

Background: I-SPY 2 is a multicenter, phase 2 trial using response-adaptive randomization within molecular subtypes defined by receptor status and MammaPrint (MP) risk to evaluate novel agents as neoadjuvant therapy for women with high-risk breast cancer. SD-101 is an investigational Toll-like receptor 9 (TLR9) agonist CpG-C class oligodeoxynucleotide that stimulates the production of IFN-α and interleukin (IL)-12, functional maturation of plasmacytoid dendritic cells, and production of cytotoxic antibodies. IT SD-101 was combined with systemic anti-PD-1 antibody Pb to investigate the antitumor and immunologic activity of this novel immunotherapeutic strategy. Methods: Women with tumors ≥ 2.5cm were eligible for screening. Only pts (pts) with HER2- disease were eligible for this treatment. Treatment included weekly P x 12 in combination with IT SD-101 2 mg/ml (1 ml for T2 tumors, 2 ml for >T3 tumors) weekly x 4, then q3 weeks x 2, and IV Pb q3 weeks x 4, followed by doxorubicin/cyclophosphamide (AC) q2-3 weeks x 4 (SD-101+Pembro 4). Pts in the control arm received weekly P x 12 followed by AC q2-3 weeks x 4. The I-SPY 2 methods have been previously published. This investigational arm was eligible for graduation (>85% chance of success in a 300-person phase 3 neoadjuvant trial) in 3 of 10 pre-defined signatures: HER2-, hormone receptor (HR)+/HER2- and HR-/HER2-. Results: 75 pts were randomized and evaluable in SD-101+Pembro 4 treatment arm. The control arm included 329 historical controls enrolled since April 2010. The study arm was stopped due to maximal patient accrual. Pt characteristics were balanced; 56% HR+, 44% HR-. The probability that SD-101+Pembro4 was superior to control exceeded 97% for all eligible tumor signatures, but did not reach the threshold for graduation in any of the signatures. However, it is notable that the rate of pCR/Residual Cancer Burden 1 (RCB1) in the HR+/HER2- signature was 51%. Preliminary safety events for SD-101+Pembro 4 include increased rates of fever, neutropenia, febrile neutropenia, transaminitis, and immune-related events, including adrenal insufficiency. Conclusions: The SD-101+Pembro 4 regimen was active but did not meet the pre-specified threshold for graduation in I-SPY 2. pCR/RCB 1 analysis suggests improved response in the HR+/HER-negative signature compared to control. The clinical significance of these findings needs to be weighed against the potential risk of immune-related toxicities. Clinical trial information: NCT01042379. [Table: see text]

Initiative for Molecular Profiling and Advanced Cancer Therapy (IMPACT2): Challenges and Opportunities in Conducting an MD Anderson Randomized Study in Precision Oncology

3140

Background: Precision oncology is associated with favorable outcomes in selected patients with cancer. Our first IMPACT trial (IMPACT1) demonstrated that in sequential patients with advanced cancer who had tumor molecular testing and participated in phase I clinical trials, matched targeted therapy (MTT) was associated with superior rates of response, progression-free survival (PFS) and overall survival compared with those of patients who received non-MTT. Despite the statistical significance for these outcomes, the study was non-randomized. Recognizing that it would be difficult to randomize patients we nonetheless undertook IMPACT2, a phase 2 randomized study to determine whether patients treated on the basis of tumor genomic alterations have longer PFS compared to those whose treatment is not selected on the basis of molecular alteration analysis. Methods: Patients with metastatic cancer undergo a tumor biopsy and genomic profiling. Patients are presented at tumor board and are offered to be randomized between two arms: MTT or non-MTT, when criteria (biomarker present, available clinical trial, eligibility criteria met, insurance approval) are met. In April 2019, we amended the trial to include a “patient-preference” cohort for each arm. Patients who decline randomization are offered choice of arm (ClinicalTrials.gov: NCT02152254). The primary analysis will use both randomized and patient-preference cohorts based on a Bayesian hierarchical model that “borrows” from the patient-preference cohorts to the extent to which its PFS agrees with that in the randomization cohort. Results: The key barriers randomizing patients with actionable molecular alterations are patient-related (advanced, metastatic setting requiring immediate intervening therapy; decline in performance status, organ function; or death); drug-related (FDA-approved drug available; or unavailable MTT against key driver biomarker) or financial (no insurance coverage of MTT; lack of patient resources to participate in trials). As the study spans over a few years, some investigational agents that were considered non-MTT at the time of treatment assignment were later proven to be MTT (e.g., immunotherapeutic agents targeting high tumor mutational burden); and/or were approved by the FDA. Conclusions: Although randomized trials have been considered the gold standard in drug development, such studies in the advanced metastatic setting are complicated. The benefit of Precision Oncology has been exemplified in individual patients who were treated with biomarker-selected therapy. The adaptive design of IMPACT2 enables patient randomization despite the evolving tumor biomarkers and the plethora of investigational drugs. IMPACT2 provides insights for the development of cancer genome-based medicine. Outcomesfor randomized patients are awaited. Clinical trial information: NCT02152254.

A randomized, double-blind, phase 2b proof-of-concept clinical trial in early Alzheimer's disease with lecanemab, an anti-Aβ protofibril antibody

BACKGROUND

Lecanemab (BAN2401), an IgG1 monoclonal antibody, preferentially targets soluble aggregated amyloid beta (Aβ), with activity across oligomers, protofibrils, and insoluble fibrils. BAN2401-G000-201, a randomized double-blind clinical trial, utilized a Bayesian design with response-adaptive randomization to assess 3 doses across 2 regimens of lecanemab versus placebo in early Alzheimer's disease, mild cognitive impairment due to Alzheimer's disease (AD) and mild AD dementia.

METHODS

BAN2401-G000-201 aimed to establish the effective dose 90% (ED90), defined as the simplest dose that achieves ≥90% of the maximum treatment effect. The primary endpoint was Bayesian analysis of 12-month clinical change on the Alzheimer's Disease Composite Score (ADCOMS) for the ED90 dose, which required an 80% probability of ≥25% clinical reduction in decline versus placebo. Key secondary endpoints included 18-month Bayesian and frequentist analyses of brain amyloid reduction using positron emission tomography; clinical decline on ADCOMS, Clinical Dementia Rating-Sum-of-Boxes (CDR-SB), and Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog14); changes in CSF core biomarkers; and total hippocampal volume (HV) using volumetric magnetic resonance imaging.

RESULTS

A total of 854 randomized subjects were treated (lecanemab, 609; placebo, 245). At 12 months, the 10-mg/kg biweekly ED90 dose showed a 64% probability to be better than placebo by 25% on ADCOMS, which missed the 80% threshold for the primary outcome. At 18 months, 10-mg/kg biweekly lecanemab reduced brain amyloid (-0.306 SUVr units) while showing a drug-placebo difference in favor of active treatment by 27% and 30% on ADCOMS, 56% and 47% on ADAS-Cog14, and 33% and 26% on CDR-SB versus placebo according to Bayesian and frequentist analyses, respectively. CSF biomarkers were supportive of a treatment effect. Lecanemab was well-tolerated with 9.9% incidence of amyloid-related imaging abnormalities-edema/effusion at 10 mg/kg biweekly.

CONCLUSIONS

BAN2401-G000-201 did not meet the 12-month primary endpoint. However, prespecified 18-month Bayesian and frequentist analyses demonstrated reduction in brain amyloid accompanied by a consistent reduction of clinical decline across several clinical and biomarker endpoints. A phase 3 study (Clarity AD) in early Alzheimer's disease is underway.

TRIAL REGISTRATION

Clinical Trials.gov NCT01767311 .

Abstract PS4-08: Biomarker analysis of paclitaxel, ganitumab, and metformin (PGM) therapy in the I-SPY2 neoadjuvant clinical trial

I-SPY2 is a neoadjuvant trial evaluating experimental therapies in combination with cytotoxic chemotherapy compared to chemotherapy alone with the primary endpoint of pathologic complete response (pCR). Abundant preclinical evidence suggested the type I insulin-like growth factor receptor (IGF-1R) regulated breast cancer growth, although multiple clinical trials did not show benefit. We were the first to report the results of a monoclonal IGF-1R antibody ganitumab (G) in combination with chemotherapy. PGM followed by doxorubicin/cyclophosphamide (AC) did not result in substantial increases in pCR when compared to P followed by AC. In this report, we examined several potential predictive biomarkers.

IGF-1R inhibitors induce hyperglycemia and we examined hemoglobin A1C (HgbA1c) as a measure of glucose control in patients before and after PGM therapy. 106 patients received PGM and 104 patients had baseline HgbA1c with a median of 5.4%. However, 27% (28/104) had levels greater than 5.7% the upper limit of normal as defined by the NIDDK. 4 of 104 had HgbA1c greater than 6.5%, a level associated with type 2 diabetes. pCR rates are similar between patients with baseline HgbA1c ≤5.7% (21%) vs. &gt;5.7% (25%) (Fisher test p=0.79). 72 of these patients had an additional HgbA1c during the course of PGM therapy. For patients with HgbA1c ≤5.7%, 27% (14/52) had subsequent elevation above 5.7% after PGM. For patients with a baseline HgbA1C &gt;5.7%, all 20 patients continued to have elevated levels through PGM.

We also examined pre-treatment tumor gene expression profiles derived from custom Agilent 44K full-genome microarrays. We studied 11 genes associated with the IGF-1R signaling (IGF1, IGF2, IGF1R, INSR, IGFBP2, IRS1, IRS2, IGFBP3, IGFBP4, IGFBP5, CDH1), the IGFBP5/IGFBP4 ratio, and two IGFR expression signatures (Creighton, et al. J Clin Oncol 26:4078 2008 PMID: 18757322; Mu, et al. Breast Cancer Res Treat 133:321 2012 PMID: 22297468). The 2 signatures evaluated: the IGF1 ligand score and the IGF1-R signature are anti-correlated (Rp= - 0.79). In the population as a whole, lower levels of IRS1 and IGFBP5 significantly associated with response to PGM (likelihood ratio test (LR) p&lt; 0.05), as do lower levels of the IGF1 ligand score and higher levels of the IGF-1R signature. However, levels of IRS1 and the two expression signatures also trend toward or are significantly associated with response in the control arm; and treatment interactions for all four biomarkers are non-significant (LR p&gt;0.05). Therefore, none of these biomarkers qualify as specific predictors of response to PGM. Similarly, high MammaPrint scores (MP2) were associated with higher pCR scores in both PGM and Control arms. Previous gene expression profiles were divided into tertiles (low, intermediate, high). Similar to the continuous case, IGF1Rsig-class associates with pCR in both the PGM and control arms (Fisher test p=0.033 and 0.044, respectively), and thus also fails as a specific predictor of response to PGM.

We conclude that PGM therapy results in worsening of glucose control and likely increases serum insulin levels. While IGF gene expression profiling associated with treatment response, they were not specific for PGM. Further, biomarker analysis and strategies to control glucose will be needed to optimize anti-IGF-1R therapies.

Citation Format: Douglas Yee, Paul Haluska, Denise M Wolf, Christina Yau, Amy Wilson, I-SPY2 TRIAL Consortium, Angela DeMichele, Claudine Isaacs, Jane Perlmutter, Joan Venticinque, Hope S Rugo, Richard Schwab, Nola M Hylton, W Fraser Symmans, Michelle E Melisko, Teresa L Helsten, Laura J van't Veer, Donald A Berry, Laura J Esserman. Biomarker analysis of paclitaxel, ganitumab, and metformin (PGM) therapy in the I-SPY2 neoadjuvant clinical trial [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-08.

Neoadjuvant Therapy for Melanoma: A U.S. Food and Drug Administration-Melanoma Research Alliance Public Workshop

Tremendous progress has been made in treating patients with metastatic melanoma over the past decade. In that timeframe, the FDA has approved 12 novel treatments for patients with advanced unresectable melanoma, comprising both kinase-targeted therapies and immune checkpoint inhibitors (ICI), and five treatments for adjuvant (postoperative) use in patients with high-risk resectable stage III melanoma. It is not known whether outcomes can be further improved by administering kinase inhibitors or ICI in the neoadjuvant (presurgical) setting in patients with high-risk resectable melanomas. Noting research community interest in exploring the neoadjuvant approach for treating melanoma and recognizing that early harmonization of methodologies may expedite the development of therapeutics in this space, the FDA and Melanoma Research Alliance convened a public workshop on November 6, 2019, in National Harbor, Maryland, to discuss key issues. The workshop consisted of 23 faculty and included more than 250 live participants. Topics discussed included opportunities for advancing novel endpoints for regulatory purposes as well as translational research, clinical trial design considerations, and strategies for optimizing patient selection while mitigating risk.

A cost/benefit analysis of clinical trial designs for COVID-19 vaccine candidates

We compare and contrast the expected duration and number of infections and deaths averted among several designs for clinical trials of COVID-19 vaccine candidates, including traditional and adaptive randomized clinical trials and human challenge trials. Using epidemiological models calibrated to the current pandemic, we simulate the time course of each clinical trial design for 756 unique combinations of parameters, allowing us to determine which trial design is most effective for a given scenario. A human challenge trial provides maximal net benefits-averting an additional 1.1M infections and 8,000 deaths in the U.S. compared to the next best clinical trial design-if its set-up time is short or the pandemic spreads slowly. In most of the other cases, an adaptive trial provides greater net benefits.

Clinical Validation of a Machine-learning-derived Signature Predictive of Outcomes from First-line Oxaliplatin-based Chemotherapy in Advanced Colorectal Cancer

PURPOSE

FOLFOX, FOLFIRI, or FOLFOXIRI chemotherapy with bevacizumab is considered standard first-line treatment option for patients with metastatic colorectal cancer (mCRC). We developed and validated a molecular signature predictive of efficacy of oxaliplatin-based chemotherapy combined with bevacizumab in patients with mCRC.

EXPERIMENTAL DESIGN

A machine-learning approach was applied and tested on clinical and next-generation sequencing data from a real-world evidence (RWE) dataset and samples from the prospective TRIBE2 study resulting in identification of a molecular signature, FOLFOXai. Algorithm training considered time-to-next treatment (TTNT). Validation studies used TTNT, progression-free survival, and overall survival (OS) as the primary endpoints.

RESULTS

A 67-gene signature was cross-validated in a training cohort (N = 105) which demonstrated the ability of FOLFOXai to distinguish FOLFOX-treated patients with mCRC with increased benefit from those with decreased benefit. The signature was predictive of TTNT and OS in an independent RWE dataset of 412 patients who had received FOLFOX/bevacizumab in first line and inversely predictive of survival in RWE data from 55 patients who had received first-line FOLFIRI. Blinded analysis of TRIBE2 samples confirmed that FOLFOXai was predictive of OS in both oxaliplatin-containing arms (FOLFOX HR, 0.629; P = 0.04 and FOLFOXIRI HR, 0.483; P = 0.02). FOLFOXai was also predictive of treatment benefit from oxaliplatin-containing regimens in advanced esophageal/gastro-esophageal junction cancers, as well as pancreatic ductal adenocarcinoma.

CONCLUSIONS

Application of FOLFOXai could lead to improvements of treatment outcomes for patients with mCRC and other cancers because patients predicted to have less benefit from oxaliplatin-containing regimens might benefit from alternative regimens.

Association of Measurable Residual Disease With Survival Outcomes in Patients With Acute Myeloid Leukemia: A Systematic Review and Meta-analysis

Importance

Measurable residual disease (MRD) refers to neoplastic cells that cannot be detected by standard cytomorphologic analysis. In patients with acute myeloid leukemia (AML), determining the association of MRD with survival may improve prognostication and inform selection of efficient clinical trial end points.

Objective

To examine the association between MRD status and disease-free survival (DFS) and overall survival (OS) in patients with AML using scientific literature.

Data Sources

Clinical studies on AML published between January 1, 2000, and October 1, 2018, were identified via searches of PubMed, Embase, and MEDLINE.

Study Selection

Literature search and study screening were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Studies that assessed DFS or OS by MRD status in patients with AML were included. Reviews, non-English-language articles, and studies reporting only outcomes after hematopoietic cell transplantation or those with insufficient description of MRD information were excluded.

Data Extraction and Synthesis

Study sample size, median patient age, median follow-up time, MRD detection method, MRD assessment time points, AML subtype, specimen source, and survival outcomes were extracted. Meta-analyses were performed separately for DFS and OS using bayesian hierarchical modeling.

Main Outcomes and Measures

Meta-analyses of survival probabilities and hazard ratios (HRs) were conducted for OS and DFS according to MRD status.

Results

Eighty-one publications reporting on 11 151 patients were included. The average HR for achieving MRD negativity was 0.36 (95% bayesian credible interval [CrI], 0.33-0.39) for OS and 0.37 (95% CrI, 0.34-0.40) for DFS. The estimated 5-year DFS was 64% for patients without MRD and 25% for those with MRD, and the estimated OS was 68% for patients without MRD and 34% for those with MRD. The association of MRD negativity with DFS and OS was significant for all subgroups, with the exception of MRD assessed by cytogenetics or fluorescent in situ hybridization.

Conclusions and Relevance

The findings of this meta-analysis suggest that achievement of MRD negativity is associated with superior DFS and OS in patients with AML. The value of MRD negativity appears to be consistent across age groups, AML subtypes, time of MRD assessment, specimen source, and MRD detection methods. These results support MRD status as an end point that may allow for accelerated evaluation of novel therapies in AML.

Association of Event-Free and Distant Recurrence-Free Survival With Individual-Level Pathologic Complete Response in Neoadjuvant Treatment of Stages 2 and 3 Breast Cancer: Three-Year Follow-up Analysis for the I-SPY2 Adaptively Randomized Clinical Trial

Importance

Pathologic complete response (pCR) is a known prognostic biomarker for long-term outcomes. The I-SPY2 trial evaluated if the strength of this clinical association persists in the context of a phase 2 neoadjuvant platform trial.

Objective

To evaluate the association of pCR with event-free survival (EFS) and pCR with distant recurrence-free survival (DRFS) in subpopulations of women with high-risk operable breast cancer treated with standard therapy or one of several novel agents.

Design, Setting, and Participants

Multicenter platform trial of women with operable clinical stage 2 or 3 breast cancer with no prior surgery or systemic therapy for breast cancer; primary tumors were 2.5 cm or larger. Women with tumors that were ERBB2 negative/hormone receptor (HR) positive with low 70-gene assay score were excluded. Participants were adaptively randomized to one of several different investigational regimens or control therapy within molecular subtypes from March 2010 through 2016. The analysis included participants with follow-up data available as of February 26, 2019.

Interventions

Standard-of-care neoadjuvant therapy consisting of taxane treatment with or without (as control) one of several investigational agents or combinations followed by doxorubicin and cyclophosphamide.

Main Outcomes and Measures

Pathologic complete response and 3-year EFS and DRFS.

Results

Of the 950 participants (median [range] age, 49 [23-77] years), 330 (34.7%) achieved pCR. Three-year EFS and DRFS for patients who achieved pCR were both 95%. Hazard ratios for pCR vs non-pCR were 0.19 for EFS (95% CI, 0.12-0.31) and 0.21 for DRFS (95% CI, 0.13-0.34) and were similar across molecular subtypes, varying from 0.14 to 0.18 for EFS and 0.10 to 0.20 for DRFS.

Conclusions and Relevance

The 3-year outcomes from the I-SPY2 trial show that, regardless of subtype and/or treatment regimen, including 9 novel therapeutic combinations, achieving pCR after neoadjuvant therapy implies approximately an 80% reduction in recurrence rate. The goal of the I-SPY2 trial is to rapidly identify investigational therapies that may improve pCR when validated in a phase 3 confirmatory trial. Whether pCR is a validated surrogate in the sense that a therapy that improves pCR rate can be assumed to also improve long-term outcome requires further study.

Trial Registration

ClinicalTrials.gov Identifier: NCT01042379.

Hydroxychloroquine and tocilizumab therapy in COVID-19 patients-An observational study

Hydroxychloroquine has been touted as a potential COVID-19 treatment. Tocilizumab, an inhibitor of IL-6, has also been proposed as a treatment of critically ill patients. In this retrospective observational cohort study drawn from electronic health records we sought to describe the association between mortality and hydroxychloroquine or tocilizumab therapy among hospitalized COVID-19 patients. Patients were hospitalized at a 13-hospital network spanning New Jersey USA between March 1, 2020 and April 22, 2020 with positive polymerase chain reaction results for SARS-CoV-2. Follow up was through May 5, 2020. Among 2512 hospitalized patients with COVID-19 there have been 547 deaths (22%), 1539 (61%) discharges and 426 (17%) remain hospitalized. 1914 (76%) received at least one dose of hydroxychloroquine and 1473 (59%) received hydroxychloroquine with azithromycin. After adjusting for imbalances via propensity modeling, compared to receiving neither drug, there were no significant differences in associated mortality for patients receiving any hydroxychloroquine during the hospitalization (HR, 0.99 [95% CI, 0.80-1.22]), hydroxychloroquine alone (HR, 1.02 [95% CI, 0.83-1.27]), or hydroxychloroquine with azithromycin (HR, 0.98 [95% CI, 0.75-1.28]). The 30-day unadjusted mortality for patients receiving hydroxychloroquine alone, azithromycin alone, the combination or neither drug was 25%, 20%, 18%, and 20%, respectively. Among 547 evaluable ICU patients, including 134 receiving tocilizumab in the ICU, an exploratory analysis found a trend towards an improved survival association with tocilizumab treatment (adjusted HR, 0.76 [95% CI, 0.57-1.00]), with 30 day unadjusted mortality with and without tocilizumab of 46% versus 56%. This observational cohort study suggests hydroxychloroquine, either alone or in combination with azithromycin, was not associated with a survival benefit among hospitalized COVID-19 patients. Tocilizumab demonstrated a trend association towards reduced mortality among ICU patients. Our findings are limited to hospitalized patients and must be interpreted with caution while awaiting results of randomized trials. Trial Registration: Clinicaltrials.gov Identifier: NCT04347993.

GBM AGILE: A global, phase II/III adaptive platform trial to evaluate multiple regimens in newly diagnosed and recurrent glioblastoma

TPS2579

Background: Glioblastoma (GBM) is an aggressive brain tumor with few effective therapies and is invariably fatal. Developing new therapies for patients with GBM requires focused interaction between industry, academia, nonprofits, patient advocacy, and health authorities, and novel approaches to clinical trials. Industry is wary of developing drugs for GBM due to the high failure rate and high cost of drug development. GBM Adaptive Global Innovative Learning Environment (GBM AGILE) Trial was designed by over 130 global key opinion leaders in consultation with health authorities to provide an optimal mechanism for phase II/III development in GBM. The Sponsor of GBM AGILE is the Global Coalition for Adaptive Research (GCAR), a non-profit organization. GCAR’s mission is to speed the discovery and development of treatments for patients with rare and deadly diseases by serving as sponsor of innovative trials. Methods: GBM AGILE is an international, seamless phase II/III platform trial designed to evaluate multiple therapies in newly diagnosed and recurrent GBM. Its goals are to identify effective therapies for GBM and match effective therapies with patient subtypes, with data generated to support regulatory filing for new drug applications. Bayesian response adaptive randomization is used within subtypes of the disease to assign participants to investigational arms based on their performance. The primary endpoint is overall survival. The trial is being conducted under a master Investigational New Drug Application/Clinical Trial Agreement and Master Protocol, allowing multiple drugs/drug combinations from different pharmaceutical companies to be evaluated simultaneously and/or over time. The plan is to add experimental therapies as new information is identified and remove therapies as they complete their individual evaluation against a common control. GBM AGILE received IND approval from the FDA in April 2019, enrolling its first patient in June 2019. Site activation is ongoing in the US, with approximately 40 US planned. The trial received CTA approval from Health Canada in January 2020. Expansion to Europe, China, and Australia is also underway. Clinical trial information: NCT03970447 .

Effect of Pembrolizumab Plus Neoadjuvant Chemotherapy on Pathologic Complete Response in Women With Early-Stage Breast Cancer: An Analysis of the Ongoing Phase 2 Adaptively Randomized I-SPY2 Trial

Importance

Approximately 25% of patients with early-stage breast cancer who receive (neo)adjuvant chemotherapy experience a recurrence within 5 years. Improvements in therapy are greatly needed.

Objective

To determine if pembrolizumab plus neoadjuvant chemotherapy (NACT) in early-stage breast cancer is likely to be successful in a 300-patient, confirmatory randomized phase 3 neoadjuvant clinical trial.

Design, Setting, and Participants

The I-SPY2 study is an ongoing open-label, multicenter, adaptively randomized phase 2 platform trial for high-risk, stage II/III breast cancer, evaluating multiple investigational arms in parallel. Standard NACT serves as the common control arm; investigational agent(s) are added to this backbone. Patients with ERBB2 (formerly HER2)-negative breast cancer were eligible for randomization to pembrolizumab between November 2015 and November 2016.

Interventions

Participants were randomized to receive taxane- and anthracycline-based NACT with or without pembrolizumab, followed by definitive surgery.

Main Outcomes and Measures

The primary end point was pathologic complete response (pCR). Secondary end points were residual cancer burden (RCB) and 3-year event-free and distant recurrence-free survival. Investigational arms graduated when demonstrating an 85% predictive probability of success in a hypothetical confirmatory phase 3 trial.

Results

Of the 250 women included in the final analysis, 181 were randomized to the standard NACT control group (median [range] age, 47 [24.77] years). Sixty-nine women (median [range] age, 50 [27-71] years) were randomized to 4 cycles of pembrolizumab in combination with weekly paclitaxel followed by AC; 40 hormone receptor (HR)-positive and 29 triple-negative. Pembrolizumab graduated in all 3 biomarker signatures studied. Final estimated pCR rates, evaluated in March 2017, were 44% vs 17%, 30% vs 13%, and 60% vs 22% for pembrolizumab vs control in the ERBB2-negative, HR-positive/ERBB2-negative, and triple-negative cohorts, respectively. Pembrolizumab shifted the RCB distribution to a lower disease burden for each cohort evaluated. Adverse events included immune-related endocrinopathies, notably thyroid abnormalities (13.0%) and adrenal insufficiency (8.7%). Achieving a pCR appeared predictive of long-term outcome, where patients with pCR following pembrolizumab plus chemotherapy had high event-free survival rates (93% at 3 years with 2.8 years' median follow-up).

Conclusions and Relevance

When added to standard neoadjuvant chemotherapy, pembrolizumab more than doubled the estimated pCR rates for both HR-positive/ERBB2-negative and triple-negative breast cancer, indicating that checkpoint blockade in women with early-stage, high-risk, ERBB2-negative breast cancer is highly likely to succeed in a phase 3 trial. Pembrolizumab was the first of 10 agents to graduate in the HR-positive/ERBB2-negative signature.

Trial Registration

ClinicalTrials.gov Identifier: NCT01042379.

Abstract P6-02-01: The effect of background parenchymal enhancement on the predictive performance of functional tumor volume measured in MRI

Background: Strong background parenchymal enhancement (BPE) may cause overestimation in tumor volume measured from dynamic contrast-enhanced (DCE) MRI, which may adversely affect the ability of MR tumor volume to predict treatment outcome for patients undergoing neoadjuvant chemotherapy (NAC). Specifically, an overestimation of tumor volume can result in misclassification of patients with complete pathologic response (pCR) as non-responders, leading to less confidence in MRI prediction. As well, overestimation of extent of disease might lead to more aggressive surgical therapy than necessary. This study investigated whether high BPE in the contralateral breast influences the predictive performance of MRI-measured functional tumor volume (FTV) for patients with locally advanced breast cancer undergoing NAC.

Methods: patients (n=990) enrolled in the I-SPY 2 TRIAL who were randomized to the graduated experimental drug arms or controls from 2010 to 2016 were analyzed. Each patient had 4 MRI exams: pre-NAC (T0), after 3 weeks of NAC (T1), between NAC regimens (T2), and post-NAC (T3). FTV was calculated at each MRI exam by summing voxels meeting enhancement thresholds. Background parenchymal enhancement (BPE) in the contralateral breast was calculated automatically as mean percentage enhancement on the early (nominal 150sec post-contrast) image in the fibroglandular tissue segmented from 5 continuous axial slices centered in the inferior-to-superior stack. For each treatment time point, patients having both FTV and BPE measurements were included in the analysis. The area under the ROC curve (AUC) was estimated as the association between FTV and pCR at T1, T2, and T3. The analysis was conducted in the full patient cohort and in sub-cohorts defined by hormone receptor (HR) and HER2 status. In each patient cohort, a cut-off BPE value was selected to classify patients with high vs. low BPE by testing AUCs estimated with low-BPE patients reached maximum when the cut-off value varied from median to maximum in steps of 10%.

Results: Out of 990 patients, 878 had pCR outcome data (pCR or non-pCR, pCR rate = 35%). Table 1 shows the number of patients, pCR rate, and AUC of FTV for predicting pCR using all patients available vs. a subset patients with low BPE (&lt; BPE cut-off). In the full cohort, AUC increased slightly across all time points after patients with high BPE were removed. In the HR+/HER2- subtype, AUC increased at T1 after removal of cases with high BPE (0.65 vs. 0.71). For HR-/HER2+, AUC increased substantially after removal of high BPE cases (0.65 to 0.86 at T1, 0.71 to 0.87 at T2, and 0.71 to 0.89 at T3), with greater improvement at the early time point (T1) compared to later time points (T2 and T3). Only a slight improvement in the AUC was observed in the HR+/HER2+ and HR-/HER2- subtypes across all time points.

Conclusions: High background parenchymal enhancement adversely affected the predictive performance of functional tumor volume measured by DCE-MRI, at early treatment time point for HR+/HER2- and across all time points for HR-/HER2+ cancer subtype. The adverse effect might be offset using subtype-optimized enhancement threshold in calculating functional tumor volume.

Table 1 Effect of BPE on the prediction of pCR using FTV at various treatment time pointsT1T2T3npCR rateAUCBPE cut-offnpCR rateAUCBPE cut-offnpCR rateAUCBPE cut-offFullAll64734%0.662762334%0.701761134%0.6925Subset45334%0.6831133%0.7230534%0.72HR+/HER2-All26218%0.651924918%0.718225518%0.7519Subset13118%0.7124818%0.7120419%0.76HR+/HER2+All10636%0.642110538%0.62269634%0.7120Subset5332%0.668438%0.665740%0.73HR-/HER2+All5175%0.65204774%0.71204973%0.7116Subset3073%0.862871%0.872475%0.89HR-/HER2-All22842%0.682822243%0.751821143%0.6916Subset15940%0.7111137%0.7810540%0.75

Citation Format: Wen Li, Natsuko Onishi, David C Newitt, Roy Harnish, Ella F Jones, Lisa J Wilmes, Jessica Gibbs, Elissa Price, Bonnie N Joe, A. Jo Chien, Donald A Berry, Judy C Boughey, Kathy S Albain, Amy S Clark, Kirsten K Edmiston, Anthony D Elias, Erin D Ellis, David M Euhus, Heather S Han, Claudine Isaacs, Qamar J Khan, Julie E Lang, Janice Lu, Jane L Meisel, Zaha Mitri, Rita Nanda, Donald W Northfelt, Tara Sanft, Erica Stringer-Reasor, Rebecca K Viscusi, Anne M Wallace, Douglas Yee, Rachel Yung, Michelle E Melisko, Jane Perlmutter, Hope S Rugo, Richard Schwab, W. Fraser Symmans, Laura J van't Veer, Christina Yau, Smita M Asare, Angela DeMichele, Sally Goudreau, Hiroyuki Abe, Deepa Sheth, Dulcy Wolverton, Kelly Fountain, Richard Ha, Ralph Wynn, Erin P Crane, Charlotte Dillis, Theresa Kuritza, Kevin Morley, Michael Nelson, An Church, Bethany Niell, Jennifer Drukteinis, Karen Y Oh, Neda Jafarian, Kathy Brandt, Sadia Choudhery, Dae Hee Bang, Christiane Mullins, Stefanie Woodard, Kathryn W Zamora, Haydee Ojeda-Fornier, Mohammad Eghedari, Pulin Sheth, Linda Hovanessian-Larsen, Mark Rosen, Elizabeth S McDonald, Michael Spektor, Marina Giurescu, Mary S Newell, Michael A Cohen, Elise Berman, Constance Lehman, William Smith, Kim Fitzpatrick, Marisa H Borders, Wei Yang, Basak Dogan, Laura J Esserman, Nola M Hylton. The effect of background parenchymal enhancement on the predictive performance of functional tumor volume measured in MRI [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-02-01.

Abstract P3-11-02: Evaluation of patritumab/paclitaxel/trastuzumab over standard paclitaxel/trastuzumab in early stage, high-risk HER2 positive breast cancer: Results from the neoadjuvant I-SPY 2 trial

Background: I-SPY2 is a multicenter, phase 2 trial using response-adaptive randomization within biomarker subtypes to evaluate novel agents as neoadjuvant therapy for high-risk breast cancer. The primary endpoint is pathologic complete response (pCR) at surgery. The goal is to identify (graduate) regimens with ≥ 85% Bayesian predictive probability of success (i.e., demonstrating superiority to control) in a future 300-patient phase 3 1:1 randomized neoadjuvant trial with pCR endpoint within signatures defined by hormone-receptor (HR), HER2, and MammaPrint (MP) status. Regimens may leave the trial for futility (&lt; 10% probability of success), maximum sample size accrual (with probability of success ≥ 10% and &lt; 85%), or safety concerns as recommended by the independent DSMB. For HER2+ patients, the I-SPY2 control arm was 12 weekly cycles of paclitaxel+trastuzumab (TH, control) followed by doxorubicin/cyclophosphamide (AC) q2-3 weeks x4 and surgery. Patritumab is a fully human monoclonal antibody that inhibits HER3. In this experimental arm for HER2+ patients, patritumab was given q3w x 4 cycles (18mg/kg loading dose followed by 9mg/kg/dose) concurrent with paclitaxel and trastuzumab q1w x 12 weeks (PTH, treatment), followed by AC q2-3w.

Methods: Women with tumors ≥ 2.5cm were eligible for screening. MP low/HR+ tumors were ineligible. MRI scans (baseline, 3 weeks after start of therapy, prior to AC, and prior to surgery) were used in a longitudinal statistical model to predict pCR for individual patients. Analysis was intention to treat. Patients who switched to non-protocol therapy count as non-pCR. Patients on treatment arm therapy at the time of arm closure are non-evaluable. Graduation potential was in 3 of 10 pre-defined signatures: all HER2+, HR-/HER2+, and HR+/HER2+.

Results: The PTH regimen was stopped at the recommendation of the Safety Working Group and DSMB based on a safety event (bilateral sensorineural hearing loss, Gr 3) observed in one patient. At the time of arm closure, N=31 patients had received PTH treatment; 4 patients receiving PTH were changed to non-protocol therapy and removed from the analysis. The final estimated pCR report will consider 27 PTH and 31 TH as evaluable patients. Accrual was insufficient to assess graduation, however, there appears to be good signal in the HER2+HR- but not HER2+HR+ signatures.

I-SPY 2 TRIAL Est. pCR at time of arm closureSignaturesPTH (Treatment)N= 31TH (Control)N = 31All (HER2+)0.40 (0.22 - 0.59), n=310.23 (0.09 - 0.37), n=31HR-/HER2+0.64 (0.36 - 0.91), n=110.30 (0.12 - 0.47), n=12HR+/HER2+0.28 (0.08 - 0.48), n=200.20 (0.06 - 0.34), n=19

HR+/HER2+0.28 (0.08 - 0.48), n=200.20 (0.06 - 0.34), n=19The patient who developed Gr3 sensorineural hearing loss 6 days after the 2nd patritumab (and 4th paclitaxel/trastuzumab) treatment, did not recover her hearing after patritumab was stopped, and also reported Gr3 vulvovaginal pain, vulvitis, and vaginal inflammation. Other gynecological symptoms in the PTH arm include: 1 pt with Gr1 vaginal hemorrhage, and 1 pt with Gr2 dyspareunia. There was a higher frequency of Gr3 hypokalaemia (12.5% vs. 3.2%). One pt in the PTH arm reported Gr3 small intestinal obstruction which resolved with conservative management.

Conclusion: The I-SPY 2 study aims to assess the probability that investigational regimens will be successful in a phase 3 neoadjuvant trial; PTH was stopped due to safety concerns, although there was activity in the HER2+ HR- signature. This is the first report of Gr3 hearing loss associated with patritumab/paclitaxel/trastuzumab, and thus attribution is uncertain.

Citation Format: Teresa L Helsten, Shelly S Lo, Christina Yau, Kevin Kalinsky, Anthony D Elias, Anne M Wallace, A. Jo Chien, Janice Lu, Julie E Lang, Kathy S Albain, Erica Stringer-Reasor, Amy S Clark, Judy C Boughey, Erin D Ellis, Douglas Yee, Angela DeMichele, Claudine Isaacs, Jane Perlmutter, Hope S Rugo, Richard Schwab, Nola M. Hylton, W. Fraser Symmans, Michelle E Melisko, Laura J van't Veer, Amy Wilson, Ruby Singhrao, Smita M Asare, Ashish Sanil, Donald A Berry, Laura J Esserman. Evaluation of patritumab/paclitaxel/trastuzumab over standard paclitaxel/trastuzumab in early stage, high-risk HER2 positive breast cancer: Results from the neoadjuvant I-SPY 2 trial [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-11-02.

Abstract P3-09-02: Evaluation of a novel agent plus standard neoadjuvant therapy in early stage, high-risk HER2 negative breast cancer: Results from the I-SPY 2 TRIAL

Background: I-SPY2 is a multicenter, response-adaptive randomization phase 2 trial to evaluate novel agents when added to standard neoadjuvant therapy for women with high-risk stage II/III breast cancer - weekly paclitaxel + investigational treatment x 12 wks followed by doxorubicin & cyclophosphamide(AC) q3 wks x 4 vs. weekly paclitaxel/AC (control). The primary endpoint is pathologic complete response (pCR). The goal for all investigational arms is to identify/graduate regimens with ≥85% Bayesian predictive probability of success (i.e. demonstrating superiority to control) in a future 300-patient phase 3 1:1 randomized neoadjuvant trial with a pCR endpoint within signatures defined by hormone-receptor (HR) & HER2 status & MammaPrint (MP). Findings from the graduated, previously reported Pembro4 arm (Nanda et al, ASCO 2017) supported investigation of de-escalating therapy, and determining if pembrolizumab (an anti-PD-1 antibody) alone q3 wks x 4 after weekly paclitaxel x 12 wks + pembrolizumab q3 wks x 4 was sufficient to sustain response without AC.

Methods: Women with tumors ≥2.5cm were eligible for screening. MP low/HR+ were ineligible. MRI scans (at baseline, 3 wks, 12 wks, and prior to surgery) were used in a longitudinal statistical model to predict pCR for individual patients (pts). Pts who receive non-protocol therapy (e.g., carboplatin or AC for the Pembro8-noAC arm) count as non-pCR. Pembro8-noAC was open to HER2- pts for evaluation in 3 of 10 pre-defined signatures: HER2-, HR+/HER2-, and HR-/HER2-. Regimens exit the trial for futility (&lt;10% probability of success), maximum sample size accrual (10% &lt;probability of success &lt;85%), or safety as recommended by the independent DSMB.

Results: Pembro8-noAC was randomized to 73 pts, 3 of whom progressed while receiving pembrolizumab alone on study. Randomization to this arm continued after the first report because the rate of progression during AC over the course of the trial was estimated to be 6.5% based on serial MRI studies. However, notification of the third case prompted the study team to ask the DSMB for the summary response for this arm. Although it did not meet formal stopping rules for either graduation or futility, Pembro8-noAC was not near the target threshold pCR rates of 60% for HR-/HER2- and 30% for HR+/HER2+. As a result of this information, combined with the on-treatment progressions, assignment to Pembro8-noAC was discontinued. Treatment with pembrolizumab alone was no longer allowed due to the potential concern for progression, and investigators were given the option to administer AC with pembrolizumab or proceed with definitive surgery following the 12 weeks of paclitaxel + pembrolizumab. 34 pts had surgery results at the time the study was closed. Of the remaining 39 pts, 34 pts have on-therapy MRI assessments. Estimated pCR rates were based on all pts with information at the time (see table). Immune-related adverse events included grade 3 colitis (n=2), grade 3 pneumonitis (n=1), grade 3 transaminitis (n=1), grade 3 hypothyroidism (n=1), and grade 1-2 adrenal insufficiency (n=5).

Conclusion: Although Pembro8-noAC is performing at least as well as standard paclitaxel/AC, the likelihood is very low that the regimen would be successful in a phase 3 trial. Pembrolizumab alone following 12 weeks of paclitaxel + pembrolizumab was not sufficient to sustain a response. This was quickly assessed with a small number of patients.

Estimated pCR rateSignature(95% prob interval)Pembro8-noACControlHER2-0.210.2(0.09-0.32)(0.15-0.25)HR-/HER2-0.270.27(0.09-0.45)(0.19-0.35)HR+/HER2-0.150.15(0.01-0.29)(0.09-0.20)

Citation Format: Minetta C. Liu, Patricia A Robinson, Christina Yau, Anne M Wallace, A. Jo Chien, Erica Stringer-Reasor, Rita Nanda, Douglas Yee, Kathy S Albain, Judy C Boughey, Heather S Han, Anthony D Elias, Kevin Kalinsky, Amy S Clark, Kathleen Kemmer, Claudine Isaacs, Julie E Lang, Janice Lu, Tara Sanft, Angela DeMichele, Nola M Hylton, Michelle E Melisko, Jane Perlmutter, Hope S Rugo, Richard Schwab, W. Fraser Symmans, Laura J van't Veer, Patricia K Haugen, Amy Wilson, Ruby Singhrao, Smita Asare, Ashish Sanil, Donald A Berry, Laura J Esserman. Evaluation of a novel agent plus standard neoadjuvant therapy in early stage, high-risk HER2 negative breast cancer: Results from the I-SPY 2 TRIAL [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-09-02.

Abstract P6-10-06: Amsterdam 70-gene profile (MammaPrint) low risk, even in the HER2 positive subset, identifies a population of women with lower early risk for recurrence despite low response rates to chemotherapy and to HER2 targeted therapy

Importance: It is essential to refine the populations most likely to benefit from targeted chemotherapy combinations.

Background: MINDACT showed that molecularly low risk patients, as assessed by the Amsterdam 70-gene profile MammaPrint® (Agendia) (MP), did not benefit from chemotherapy. In the I-SPY2 trial, MP low risk Hormone Receptor (HR) positive/HER2 negative patients are not eligible; however, HR negative or HER2 positive patients were considered high risk and included for treatment with chemotherapy plus novel agents. The neoadjuvant setting provides an opportunity to evaluate whether molecularly low risk HER2 positive patients are good candidates for neoadjuvant chemo/anti-HER2 therapy, where pathologic complete response (pCR) and 3-year outcomes are measured.

Objective: To evaluate and further characterize the fraction of and outcomes for patients molecular low-risk disease in the I-SPY2 trial.

Methods: The I-SPY2 platform trial is an ongoing multicenter phase 2 multi-arm study utilizing adaptive design and evaluating efficacy and tolerability of investigational agents in combination with standard-of-care chemotherapy for patients with high-risk anatomic stage II/III breast cancer. Patients with HR+HER2- MP low-risk tumors are not eligible. All enrolled patients undergo pretreatment biopsy for genomic evaluation of early recurrence risk with MP for risk stratification and with the 80-gene BluePrint® (Agendia) test for intrinsic subtype classification. Primary endpoint of the study is pCR in breast and lymph nodes (ypT0/is, ypN0). Secondary outcomes included event-free survival (EFS) and distant-recurrence free survival (DRFS). Following standard neoadjuvant treatment with or without a concomitant investigational agent, patients are followed for long-term outcomes. EFS and DRFS at 3 and 5 years in the pCR vs non-pCR groups within histologic and molecular subtypes are determined using the Kaplan Meier method.

Results: Of the 1038 enrolled patients by November 2016, 24 patients (3.2%) had molecular low-risk disease as determined by MP. Of these, 21 (87.5%) had HR+HER2+, 1 (4.2%) had HR-HER2+, and 2 (8.4%) had HR-HER2-. BluePrint expression subtyping classified 17 as luminal-type, 6 HER2 enriched-type and 1 basal type. One patient withdrew consent for follow-up. Of the 23 remaining, none achieved pCR and only one (HR+/HER2+) had an EFS event (with median follow-up of 4.3 years). Overall, EFS and DRFS data were available for 950 of the 1038 patients (as of February 2019), with median follow-up of 3.8 years. Of the 173 HR+HER2+ in this cohort, 20 (11.6%) had molecular low-risk tumors. The EFS and DRFS for the 173 HER2+HR+ pCR group is 97% and 98% (non-pCR group 89% and 94%), respectively at 3 years. Removing the molecular low-risk HER2+ patients from the denominator reveals the worse outcome for patients with non pCR: EFS 86% and DRFS 92% at 3 years. The difference is more apparent at 5 years, changing from 74% to 66% for EFS and from 81% to 75% for DRFS. Intrinsic subtypes vary and do not predict early risk.

Conclusions: I-SPY2 focuses on women with high clinical risk with only 3.2% of enrolled patients having low molecular risk tumors. However, 12% of HER+ breast cancer enrolled patients had molecular low risk tumors of which 95% were also HR+. In this group, early recurrence is very low despite absence of pCR and irrespective of intrinsic subtype. Refining the population using molecular high-risk classification of patients reveals a greater difference between the pCR and non-pCR groups within the HR+HER2+ subtype in the EFS and DRFS analysis. Clinical trial designs could address the opportunity to find more targeted and less toxic treatments for the HER2+ low molecular risk patient population.

Citation Format: Paula R Pohlmann, Christina Yau, Angela DeMichele, Claudine Isaacs, Judy C Boughey, Nola Hylton, Michelle E Melisko, Jane Perlmutter, Hope S Rugo, W. Fraser Symmans, I-SPY 2 TRIAL Consortium, Donald A Berry, Laura Esserman. Amsterdam 70-gene profile (MammaPrint) low risk, even in the HER2 positive subset, identifies a population of women with lower early risk for recurrence despite low response rates to chemotherapy and to HER2 targeted therapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-10-06.