A phase 2 trial exploring the significance of homologous recombination status in patients with platinum sensitive or platinum resistant relapsed ovarian cancer receiving combination cediranib and olaparib

OBJECTIVE

Combination cediranib/olaparib has reported activity in relapsed ovarian cancer. This phase 2 trial investigated the activity of cediranib/olaparib in relapsed ovarian cancer and its association with homologous recombination deficiency (HRD).

METHODS

Seventy patients were enrolled to cohorts of either platinum-sensitive or platinum-resistant ovarian cancer and received olaparib tablets 200 mg twice daily and cediranib tablets 30 mg once daily under a continuous dosing schedule. HRD testing was performed on pre-treatment, on-treatment and archival biopsies by sequencing key homologous recombination repair (HRR) genes and by genomic LOH analysis. The primary objective for the platinum-sensitive cohort was the association of HRD, defined as presence of HRR gene mutation, with progression-free survival (PFS). The primary objective for the platinum-resistant cohort was objective response rate (ORR), with a key secondary endpoint evaluating the association of HRD status with activity.

RESULTS

In platinum-sensitive ovarian cancer (N = 35), ORR was 77.1% (95% CI 59.9-89.6%) and median PFS was 16.4 months (95% CI 13.2-18.6). Median PFS in platinum-sensitive HRR-HRD cancers (N = 22) was 16.8 months (95% CI 11.3-18.6), and 16.4 months (95% CI 9.4-NA) in HRR-HR proficient cancers (N = 13; p = 0.57). In platinum-resistant ovarian cancer (N = 35), ORR was 22.9% (95% CI 10.4-40.1%) with median PFS 6.8 months (95% CI 4.2-9.1). Median PFS in platinum-resistant HRR-HRD cancers (N = 7) was 10.5 months (95% CI 3.6-NA) and 5.6 months (95% CI 3.6-7.6) in HRR-HR proficient cancers (N = 18; p = 0.23).

CONCLUSIONS

Cediranib/olaparib had clinical activity in both platinum-sensitive and -resistant ovarian cancer. Presence of HRR gene mutations was not associated with cediranib/olaparib activity in either setting.

Phase I/II Study of Combined BCL-xL and MEK Inhibition with Navitoclax and Trametinib in KRAS or NRAS Mutant Advanced Solid Tumors

PURPOSE

MEK inhibitors (MEKi) lack monotherapy efficacy in most RAS-mutant cancers. BCL-xL is an anti-apoptotic protein identified by a synthetic lethal shRNA screen as a key suppressor of apoptotic response to MEKi.

PATIENTS AND METHODS

We conducted a dose escalation study (NCT02079740) of the BCL-xL inhibitor navitoclax and MEKi trametinib in patients with RAS-mutant tumors with expansion cohorts for: pancreatic, gynecologic (GYN), non-small cell lung cancer (NSCLC), and other cancers harboring KRAS/NRAS mutations. Paired pretreatment and day 15 tumor biopsies and serial cell-free (cf)DNA were analyzed.

RESULTS

A total of 91 patients initiated treatment, with 38 in dose escalation. Fifty-eight percent had ≥3 prior therapies. A total of 15 patients (17%) had colorectal cancer, 19 (11%) pancreatic, 15 (17%) NSCLC, and 32 (35%) GYN cancers. The recommended phase II dose (RP2D) was established as trametinib 2 mg daily days 1 to 14 and navitoclax 250 mg daily days 1 to 28 of each cycle. Most common adverse events included diarrhea, thrombocytopenia, increased AST/ALT, and acneiform rash. At RP2D, 8 of 49 (16%) evaluable patients achieved partial response (PR). Disease-specific differences in efficacy were noted. In patients with GYN at the RP2D, 7 of 21 (33%) achieved a PR and median duration of response 8.2 months. No PRs occurred in patients with colorectal cancer, NSCLC, or pancreatic cancer. MAPK pathway inhibition was observed in on-treatment tumor biopsies. Reductions in KRAS/NRAS mutation levels in cfDNA correlated with clinical benefit.

CONCLUSIONS

Navitoclax in combination with trametinib was tolerable. Durable clinical responses were observed in patients with RAS-mutant GYN cancers, warranting further evaluation in this population.

Poor Concordance Between Cancer Antigen-125 and RECIST Assessment for Progression in Patients With Platinum-Sensitive Relapsed Ovarian Cancer on Maintenance Therapy With a Poly(ADP-ribose) Polymerase Inhibitor

PURPOSE

Cancer antigen-125 (CA-125) is recommended by treatment guidelines and widely used to diagnose ovarian cancer recurrence. The value of CA-125 as a surrogate for disease progression (PD) and its concordance with radiologic progression are unclear, particularly for women with platinum-sensitive relapsed ovarian cancer (PSROC) who have responded to chemotherapy and treated with maintenance poly(ADP-ribose) polymerase inhibitor (PARPi).

METHODS

In this pooled analysis of four randomized trials of maintenance PARPi or placebo (Study 19, SOLO2, ARIEL3, and NOVA), we extracted data on CA-125 PD as defined by Gynecologic Cancer InterGroup criteria and RECIST v1.1. We evaluated the concordance between CA-125 and RECIST PD and reported on the negative predictive value (NPV) and positive predictive value (PPV).

RESULTS

Of 1,262 participants (n = 818 PARPi, n = 444 placebo), 403 (32%) had CA-125 PD, and of these, 366 had concordant RECIST PD (PPV, 91% [95% CI, 88 to 93]). However, of 859 (68%) without CA-125 PD, 382 also did not have RECIST PD (NPV, 44% [95% CI, 41 to 48]). Within the treatment arms, PPV remained high (PARPi, 91% [95% CI, 86 to 94]; placebo, 91% [95% CI, 86 to 95]) but NPV was lower on placebo (PARPi, 53% [95% CI, 49 to 57]; placebo, 25% [95% CI, 20 to 31]). Of 477 with RECIST-only PD, most (95%) had a normal CA-125 at the start of maintenance therapy and the majority (n = 304, 64%) had CA-125 that remained within normal range. Solid organ recurrence without peritoneal disease was more common in those with RECIST-only PD than in those with CA-125 and RECIST PD (36% v 24%; P < .001).

CONCLUSION

In patients with PSROC treated with maintenance PARPi, almost half with RECIST PD did not have CA-125 PD, challenging current guidelines. Periodic computed tomography imaging should be considered as part of surveillance, particularly in those with a normal CA-125 at the start of maintenance therapy and on treatment.

Combined aromatase, CDK4/6 and PI3K blockade using letrozole/abemaciclib/LY3023414 in endometrial cancer

Several lines of preclinical evidence indicate that combining PI3K and CDK4/6 inhibitors may further enhance the efficacy of hormonal therapy by overcoming de novo and acquired resistance to PI3K and CDK4/6 blockade. We evaluated the combination of abemaciclib, letrozole and LY3023414 (an orally available, selective inhibitor of the class I PI3K isoforms and mTORC1/2) in recurrent endometrial cancer (EC). This study was terminated prematurely after 5 patients initiated protocol therapy due to discontinuation of further development of LY3023414. We report our findings from these patients, including one with recurrent endometrioid EC with AKT1, CTNNB1 and ESR1 hotspot mutations who had previously progressed through letrozole/everolimus and achieved a partial response to letrozole/abemaciclib/LY3023414.

Randomized Phase II Study of Gemcitabine With or Without ATR Inhibitor Berzosertib in Platinum-Resistant Ovarian Cancer: Final Overall Survival and Biomarker Analyses

PURPOSE

The multicenter, open-label, randomized phase 2 NCI-9944 study (NCT02595892) demonstrated that addition of ATR inhibitor (ATRi) berzosertib to gemcitabine increased progression-free survival (PFS) compared to gemcitabine alone (hazard ratio [HR]=0.57, one-sided log-rank P = .044, which met the one-sided significance level of 0.1 used for sample size calculation).

METHODS

We report here the final overall survival (OS) analysis and biomarker correlations (ATM expression by immunohistochemistry, mutational signature 3 and a genomic biomarker of replication stress) along with post-hoc exploratory analyses to adjust for crossover from gemcitabine to gemcitabine/berzosertib.

RESULTS

At the data cutoff of January 27, 2023 (>30 months of additional follow-up from the primary analysis), median OS was 59.4 weeks with gemcitabine/berzosertib versus 43.0 weeks with gemcitabine alone (HR 0.79, 90% CI 0.52 to 1.2, one-sided log-rank P = .18). An OS benefit with addition of berzosertib to gemcitabine was suggested in patients stratified into the platinum-free interval ≤3 months (N = 26) subgroup (HR, 0.48, 90% CI 0.22 to 1.01, one-sided log-rank P =.04) and in patients with ATM-negative/low (N = 24) tumors (HR, 0.50, 90% CI 0.23 to 1.08, one-sided log-rank P = .06).

CONCLUSION

The results of this follow-up analysis continue to support the promise of combined gemcitabine/ATRi therapy in platinum resistant ovarian cancer, an active area of investigation with several ongoing clinical trials.

Phase 1b study of mirvetuximab soravtansine, a folate receptor alpha (FRα)-targeting antibody-drug conjugate, in combination with carboplatin and bevacizumab in patients with platinum-sensitive ovarian cancer

OBJECTIVE

Evaluate the antitumor activity and safety profile of the triplet combination of mirvetuximab soravtansine (MIRV), carboplatin, and bevacizumab in recurrent, platinum-sensitive ovarian cancer.

METHODS

Participants with recurrent, platinum-sensitive epithelial ovarian, fallopian tube, or primary peritoneal cancer (1-2 prior lines of therapy) received MIRV (6 mg/kg adjusted ideal body weight), carboplatin (AUC5), and bevacizumab (15 mg/kg) once every 3 weeks. Carboplatin could be discontinued after 6 cycles per investigator discretion; continuation of MIRV+bevacizumab as maintenance therapy was permitted. Eligibility included folate receptor alpha (FRα) expression by immunohistochemistry (≥50% of cells with ≥2+ intensity; PS2+ scoring); prior bevacizumab was allowed. Tumor response, duration of response (DOR), progression-free survival (PFS), and adverse events (AEs) were assessed.

RESULTS

Forty-one participants received triplet therapy, with a median of 6, 12, and 13 cycles of carboplatin, MIRV, and bevacizumab, respectively. The confirmed objective response rate was 83% (9 complete and 25 partial responses). The median DOR was 10.9 months; median PFS was 13.5 months. AEs (any grade) occurred as expected, based on each agent's safety profile; most common were diarrhea (83%), nausea (76%), fatigue (73%), thrombocytopenia (71%), and blurred vision (68%). Most cases were mild to moderate (grade ≤2), except for thrombocytopenia, for which most drug-related discontinuations occurred, and neutropenia.

CONCLUSIONS

This triplet regimen (MIRV+carboplatin+bevacizumab) was highly active, with a tolerable AE profile in participants with recurrent, platinum-sensitive, FRα-expressing ovarian cancer. Thrombocytopenia was the primary cause of dose modifications. These outcomes compare favorably to historical data reported for platinum-based chemotherapy plus bevacizumab regimens in similar patient populations.

Experiences of patients with peritoneal carcinomatosis-related complex care needs and their caregivers

BACKGROUND

Patients with peritoneal carcinomatosis (PC) frequently undergo palliative procedures, yet these patients and their caregivers report being unprepared to manage ostomies, drains, and other complex care needs at home. The purpose of this study was to characterize the unique needs of these patients and their caregivers during care transitions.

METHODS

Patients completed measures of health status and advance care planning, caregivers completed measures of preparedness and burden, and all participants completed measures of depression and anxiety. Participants detailed their experiences in individual, semi-structured interviews. We analyzed data using descriptive statistics and conventional content analysis.

RESULTS

Sixty-one patients and 39 caregivers completed baseline measures. Twenty-four (39.3%) patients acknowledged their terminal illness and seven (11.5%) had discussed end-of-life care preferences with clinicians. Most (26/39, 66.7%) caregivers provided daily care. Among caregivers who managed symptoms, few were taught how to do so (6/20, 30%). Seven patients (11.5%) and seven caregivers (17.9%) met case criteria for anxiety, while 15 patients (24.6%) and two caregivers (5.1%) met case criteria for depression. Interview participants described a diagnosis of PC as a turning point for which there is no road map and identified the need for health systems change to minimize suffering.

CONCLUSION

Patients with PC and their caregivers are highly burdened by symptoms and care needs. Patients' prognostic understanding and advance care planning are suboptimal. Interventions that train patients with PC and their caregivers to perform clinical care tasks, facilitate serious illness conversations, and provide psychosocial support are needed.

Ultrasensitive Detection of Circulating LINE-1 ORF1p as a Specific Multicancer Biomarker

Improved biomarkers are needed for early cancer detection, risk stratification, treatment selection, and monitoring treatment response. Although proteins can be useful blood-based biomarkers, many have limited sensitivity or specificity for these applications. Long INterspersed Element-1 (LINE-1) open reading frame 1 protein (ORF1p) is a transposable element protein overexpressed in carcinomas and high-risk precursors during carcinogenesis with negligible expression in normal tissues, suggesting ORF1p could be a highly specific cancer biomarker. To explore ORF1p as a blood-based biomarker, we engineered ultrasensitive digital immunoassays that detect mid-attomolar (10-17 mol/L) ORF1p concentrations in plasma across multiple cancers with high specificity. Plasma ORF1p shows promise for early detection of ovarian cancer, improves diagnostic performance in a multianalyte panel, provides early therapeutic response monitoring in gastroesophageal cancers, and is prognostic for overall survival in gastroesophageal and colorectal cancers. Together, these observations nominate ORF1p as a multicancer biomarker with potential utility for disease detection and monitoring.

SIGNIFICANCE

The LINE-1 ORF1p transposon protein is pervasively expressed in many cancers and is a highly specific biomarker of multiple common, lethal carcinomas and their high-risk precursors in tissue and blood. Ultrasensitive ORF1p assays from as little as 25 μL plasma are novel, rapid, cost-effective tools in cancer detection and monitoring. See related commentary by Doucet and Cristofari, p. 2502. This article is featured in Selected Articles from This Issue, p. 2489.

FF-10850, a Novel Liposomal Topotecan Achieves Superior Antitumor Activity via Macrophage- and Ammonia-Mediated Payload Release in the Tumor Microenvironment

Topotecan, an approved treatment for refractory or recurrent ovarian cancer, has clinical limitations such as rapid clearance and hematologic toxicity. To overcome these limitations and maximize clinical benefit, we designed FF-10850, a dihydrosphingomyelin-based liposomal topotecan. FF-10850 demonstrated superior antitumor activity to topotecan in ovarian cancer cell line-based xenograft models, as well as in a clinically relevant DF181 platinum-refractory ovarian cancer patient-derived xenograft model. The safety profile was also improved with mitigation of hematologic toxicity. The improved antitumor activity and safety profile are achieved via its preferential accumulation and payload release triggered in the tumor microenvironment. Our data indicate that tumor-associated macrophages internalize FF-10850, resulting in complete payload release. The release mechanism also appears to be mediated by high ammonia concentration resulting from glutaminolysis, which is activated by tumor metabolic reprogramming. In ammonia-rich conditions, FF-10850 released payload more rapidly and to a greater extent than liposomal doxorubicin, a currently approved treatment for ovarian cancer. FF-10850 significantly enhanced antitumor activity in combination with carboplatin or PARP inhibitor without detrimental effects on body weight in murine xenograft models, and demonstrated synergistic antitumor activity combined with anti-PD-1 antibody with the development of tumor antigen-specific immunity. These results support phase I investigation of FF-10850 for the treatment of solid tumors including ovarian cancer (NCT04047251), and further evaluation in combination settings.

Open-Source, Step-Counting Algorithm for Smartphone Data Collected in Clinical and Nonclinical Settings: Algorithm Development and Validation Study

BACKGROUND

Step counts are increasingly used in public health and clinical research to assess well-being, lifestyle, and health status. However, estimating step counts using commercial activity trackers has several limitations, including a lack of reproducibility, generalizability, and scalability. Smartphones are a potentially promising alternative, but their step-counting algorithms require robust validation that accounts for temporal sensor body location, individual gait characteristics, and heterogeneous health states.

OBJECTIVE

Our goal was to evaluate an open-source, step-counting method for smartphones under various measurement conditions against step counts estimated from data collected simultaneously from different body locations ("cross-body" validation), manually ascertained ground truth ("visually assessed" validation), and step counts from a commercial activity tracker (Fitbit Charge 2) in patients with advanced cancer ("commercial wearable" validation).

METHODS

We used 8 independent data sets collected in controlled, semicontrolled, and free-living environments with different devices (primarily Android smartphones and wearable accelerometers) carried at typical body locations. A total of 5 data sets (n=103) were used for cross-body validation, 2 data sets (n=107) for visually assessed validation, and 1 data set (n=45) was used for commercial wearable validation. In each scenario, step counts were estimated using a previously published step-counting method for smartphones that uses raw subsecond-level accelerometer data. We calculated the mean bias and limits of agreement (LoA) between step count estimates and validation criteria using Bland-Altman analysis.

RESULTS

In the cross-body validation data sets, participants performed 751.7 (SD 581.2) steps, and the mean bias was -7.2 (LoA -47.6, 33.3) steps, or -0.5%. In the visually assessed validation data sets, the ground truth step count was 367.4 (SD 359.4) steps, while the mean bias was -0.4 (LoA -75.2, 74.3) steps, or 0.1%. In the commercial wearable validation data set, Fitbit devices indicated mean step counts of 1931.2 (SD 2338.4), while the calculated bias was equal to -67.1 (LoA -603.8, 469.7) steps, or a difference of 3.4%.

CONCLUSIONS

This study demonstrates that our open-source, step-counting method for smartphone data provides reliable step counts across sensor locations, measurement scenarios, and populations, including healthy adults and patients with cancer.

Molecular determinants of clinical outcomes of pembrolizumab in recurrent ovarian cancer: Exploratory analysis of KEYNOTE-100

OBJECTIVE

This prespecified exploratory analysis evaluated the association of gene expression signatures, tumor mutational burden (TMB), and multiplex immunohistochemistry (mIHC) tumor microenvironment-associated cell phenotypes with clinical outcomes of pembrolizumab in advanced recurrent ovarian cancer (ROC) from the phase II KEYNOTE-100 study.

METHODS

Pembrolizumab-treated patients with evaluable RNA-sequencing (n = 317), whole exome sequencing (n = 293), or select mIHC (n = 125) data were evaluated. The association between outcomes (objective response rate [ORR], progression-free survival [PFS], and overall survival [OS]) and gene expression signatures (T-cell-inflamed gene expression profile [TcellinfGEP] and 10 non-TcellinfGEP signatures), TMB, and prespecified mIHC cell phenotype densities as continuous variables was evaluated using logistic (ORR) and Cox proportional hazards regression (PFS; OS). One-sided p-values were calculated at prespecified α = 0.05 for TcellinfGEP, TMB, and mIHC cell phenotypes and at α = 0.10 for non-TcellinfGEP signatures; all but TcellinfGEP and TMB were adjusted for multiplicity.

RESULTS

No evidence of associations between ORR and key axes of gene expression was observed. Negative associations were observed between outcomes and TcellinfGEP-adjusted glycolysis (PFS, adjusted-p = 0.019; OS, adjusted-p = 0.085) and hypoxia (PFS, adjusted-p = 0.064) signatures. TMB as a continuous variable was not associated with outcomes (p > 0.05). Positive associations were observed between densities of myeloid cell phenotypes CD11c+ and CD11c+/MHCII-/CD163-/CD68- in the tumor compartment and ORR (adjusted-p = 0.025 and 0.013, respectively).

CONCLUSIONS

This exploratory analysis in advanced ROC did not find evidence for associations between gene expression signatures and outcomes of pembrolizumab. mIHC analysis suggests CD11c+ and CD11c+/MHCII-/CD163-/CD68- phenotypes representing myeloid cell populations may be associated with improved outcomes with pembrolizumab in advanced ROC.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02674061.

Relacorilant + Nab-Paclitaxel in Patients With Recurrent, Platinum-Resistant Ovarian Cancer: A Three-Arm, Randomized, Controlled, Open-Label Phase II Study

PURPOSE

Despite therapeutic advances, outcomes for patients with platinum-resistant/refractory ovarian cancer remain poor. Selective glucocorticoid receptor modulation with relacorilant may restore chemosensitivity and enhance chemotherapy efficacy.

METHODS

This three-arm, randomized, controlled, open-label phase II study (ClinicalTrials.gov identifier: NCT03776812) enrolled women with recurrent, platinum-resistant/refractory, high-grade serous or endometrioid epithelial ovarian, primary peritoneal, or fallopian tube cancer, or ovarian carcinosarcoma treated with ≤4 prior chemotherapeutic regimens. Patients were randomly assigned 1:1:1 to (1) nab-paclitaxel (80 mg/m2) + intermittent relacorilant (150 mg the day before, of, and after nab-paclitaxel); (2) nab-paclitaxel (80 mg/m2) + continuous relacorilant (100 mg once daily); or (3) nab-paclitaxel monotherapy (100 mg/m2). Nab-paclitaxel was administered on days 1, 8, and 15 of each 28-day cycle. The primary end point was progression-free survival (PFS) by investigator assessment; objective response rate (ORR), duration of response (DOR), overall survival (OS), and safety were secondary end points.

RESULTS

A total of 178 women were randomly assigned. Intermittent relacorilant + nab-paclitaxel improved PFS (hazard ratio [HR], 0.66; log-rank test P = .038; median follow-up, 11.1 months) and DOR (HR, 0.36; P = .006) versus nab-paclitaxel monotherapy, while ORR was similar across arms. At the preplanned OS analysis (median follow-up, 22.5 months), the OS HR was 0.67 (P = .066) for the intermittent arm versus nab-paclitaxel monotherapy. Continuous relacorilant + nab-paclitaxel showed numerically improved median PFS but did not result in significant improvement over nab-paclitaxel monotherapy. Adverse events were comparable across study arms, with neutropenia, anemia, peripheral neuropathy, and fatigue/asthenia being the most common grade ≥3 adverse events.

CONCLUSION

Intermittent relacorilant + nab-paclitaxel improved PFS, DOR, and OS compared with nab-paclitaxel monotherapy. On the basis of protocol-prespecified Hochberg step-up multiplicity adjustment, the primary end point did not reach statistical significance (P < .025). A phase III evaluation of this regimen is underway (ClinicalTrials.gov identifier: NCT05257408).

Pilot randomized trial of an acceptance-based telehealth intervention for women with ovarian cancer and PARP inhibitor-related fatigue

OBJECTIVE

Poly(ADP-ribose) polymerase inhibitors (PARPi) have dramatically changed treatment for advanced ovarian cancer, but nearly half of patients experience significant fatigue. We conducted a two-site pilot randomized trial to evaluate the feasibility, acceptability, and preliminary efficacy of a brief, acceptance-based telehealth intervention (REVITALIZE) designed to reduce fatigue interference in patients on PARPi.

METHODS

From June 2021 to April 2022, 44 participants were randomized 1:1 to REVITALIZE (6 weekly one-on-one sessions+booster) or enhanced usual care. Feasibility was defined as: ≥50% approach-to-consent among potentially eligible patients and ≥70% completion of 12-week follow-up assessment; acceptance was <20% participants reporting burden and <20% study withdrawal. Fatigue, anxiety, depression, and quality of life were assessed at baseline, 4-, 8- and 12-weeks.

RESULTS

Among 44 participants (mean age = 62.5 years, 81.8% stage III/IV disease), the study was feasible (56.4% approach-to-consent ratio, 86.3% completion of 12-week assessment) and acceptable (0% reporting burden, 11.3% study withdrawal). At 12-week follow-up, REVITALIZE significantly reduced fatigue interference (Cohen's d = 0.94, p = .008) and fatigue severity (d = 0.54, p = .049), and improved fatigue levels (d = 0.62, p = .04) relative to enhanced usual care. REVITALIZE also showed promise for improved fatigue self-efficacy, fatigue catastrophizing, anxiety, depression, and quality of life (ds = 0.60-0.86, p ≥ .05). Compared with enhanced usual care, REVITALIZE participants had fewer PARPi dose reductions (6.7% vs. 19.0%), and dose delays (6.7% vs. 23.8%).

CONCLUSIONS

Among fatigued adults with ovarian cancer on PARPi, a brief, acceptance-based telehealth intervention was feasible, acceptable, and demonstrated preliminary efficacy in improving fatigue interference, severity, and levels. REVITALIZE is a novel, scalable telehealth intervention worthy of further investigation.

Clinical and translational advances in ovarian cancer therapy

Ovarian cancer is an aggressive disease that is frequently detected at advanced stages and is initially very responsive to platinum-based chemotherapy. However, the majority of patients relapse following initial surgery and chemotherapy, highlighting the urgent need to develop new therapeutic strategies. In this Review, we outline the main therapeutic principles behind the management of newly diagnosed and recurrent epithelial ovarian cancer and discuss the current landscape of targeted and immune-based approaches.

Mirvetuximab soravtansine for platinum-resistant epithelial ovarian cancer

INTRODUCTION

Mirvetuximab soravtansine (mirvetuximab) is an antibody drug conjugate (ADC) comprised of a humanized folate receptor alpha (FRα)-binding monoclonal antibody attached via a cleavable linker to the cytotoxic maytansinoid molecule, DM4. FRα is expressed in several epithelial cancers, including high grade serous ovarian cancer (HGSOC). Mirvetuximab received accelerated approval by the United States Food and Drug Administration (FDA) in November 2022 based on the results of the SORAYA trial, which tested mirvetuximab for the treatment of patients with recurrent platinum resistant HGSOC with high FRα expression and showed an overall response rate (ORR) of 32.4% and a median duration of response of 6.9 months. Mirvetuximab toxicities included low grade ocular and gastrointestinal toxicities. The National Comprehensive Cancer Network (NCCN) ovarian cancer 2023 guidelines adopted mirvetuximab as 2A, and mirvetuximab combined with bevacizumab as 2B, recommendations.

AREAS COVERED

This manuscript will review the preclinical and clinical development of mirvetuximab, the toxicities associated with mirvetuximab and mitigation strategies, and future applications of mirvetuximab.

EXPERT OPINION

Mirvetuximab represents the first biomarker-directed therapy with an indication specifically for the treatment of PROC. The efficacy and favorable safety profile support further development of mirvetuximab and mirvetuximab combinations in platinum sensitive and newly diagnosed ovarian cancer.

Abstract 162: Individualizing treatment using patient derived organoids, BH3 profiling and microfluidics: A proof of concept in a patient with low-grade serous ovarian carcinoma

Background N of 1 treatment paradigms represent the pinnacle of personalized medicine in which a patient’s tumors are profiled to guide treatment. Low-grade serous ovarian cancer (LGSC) is a distinct subtype of ovarian cancer, comprising ~10% of serous carcinomas and typically characterized by a younger age of onset. Molecularly, these tumors are often characterized by alterations within the Ras signaling pathway, including KRAS mutations. Clinically, LGSC is often resistant to standard cytotoxic chemotherapy, but may have sensitivity to hormonal therapy or MEK inhibitors. Here we report on a platform and proof of concept in one LGSC patient to evaluate personalized tumor-directed therapy regimens using patient-derived organoids (PDOs), BH3 profiling and viability evaluation in 3D microfluidic devices.

Methods A patient with LGSC presented to the Dana Farber Cancer Institute and was treated with carboplatin and paclitaxel before a total abdominal hysterectomy with a bilateral salpingo-oophorectomy. Tissue was obtained under an IRB approved protocol and PDOs were established. Standard of care and non-standard of care treatments including doxorubicin, abemaciclib, letrozole, alpelisib, tamoxifen, trametinib, venetoclax, and navitoclax were evaluated by two orthogonal assays. First, they were tested for delta priming by BH3 profiling (Bhola et.al., Sci Signal. 2020 ) and second for cell viability using 3D microfluidic devices by TMRM/DRAQ7 dual-color fluorescent staining. Standard of care treatments carboplatin and paclitaxel were evaluated as individual treatments and in combination in 3D microfluidic devices.

Results We successfully established a PDO model from the patient’s tumor sample in 14 days. BH3 profiling at 24 hours and viability in 3D microfluidic devices after 6 days in treatment showed that from the eight tested drugs, the model was sensitive to navitoclax and venetoclax. Average percent change in viability was -91.5% and -89.9%, respectively, and the drugs had a dynamic BH3 profiling index of 551.4 AUC (+/- 76.63) and 488.9 AUC (+/- 21.46) with the threshold of response being &gt;175 for BH3 profiling. Trametinib showed a clear response in 3D, with an average percent change of -72.6% compared to the control but no significant response in BH3 profiling. Neither carboplatin and paclitaxel alone, nor in combination, elicited a significant change in viability. This observation was consistent with the patient’s history prior to surgery, where the tumor did not demonstrate significant clinical response to neoadjuvant carboplatin and paclitaxel therapy.

Conclusions We describe a proof of concept of a N of 1 response assessment platform for LGSC using PDOs, BH3 profiling and live/dead fluorescent staining in microfluidic devices and demonstrate that BH3 profiling and 3D viability assessment assays show good congruity.

Citation Format: Brittany Meisenheimer, Ha V. Vo, Kelley E. McQueeney, Aisha L. Saldanha, Carina Feeney, Courtney H. Qi, Swati Narayan, Jennifer D. Curtis, Marisa R. Nucci, Anthony Letai, Cloud P. Paweletz, Joyce F. Liu, Ursula A. Matulonis, Elena Ivanova. Individualizing treatment using patient derived organoids, BH3 profiling and microfluidics: A proof of concept in a patient with low-grade serous ovarian carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 162.

Validation of an open-source smartphone step counting algorithm in clinical and non-clinical settings

Background

Step counts are increasingly used in public health and clinical research to assess wellbeing, lifestyle, and health status. However, estimating step counts using commercial activity trackers has several limitations, including a lack of reproducibility, generalizability, and scalability. Smartphones are a potentially promising alternative, but their step-counting algorithms require robust validation that accounts for temporal sensor body location, individual gait characteristics, and heterogeneous health states.

Objective

Our goal was to evaluate an open-source step-counting method for smartphones under various measurement conditions against step counts estimated from data collected simultaneously from different body locations ("internal" validation), manually ascertained ground truth ("manual" validation), and step counts from a commercial activity tracker (Fitbit Charge 2) in patients with advanced cancer ("wearable" validation).

Methods

We used eight independent datasets collected in controlled, semi-controlled, and free-living environments with different devices (primarily Android smartphones and wearable accelerometers) carried at typical body locations. Five datasets (N=103) were used for internal validation, two datasets (N=107) for manual validation, and one dataset (N=45) used for wearable validation. In each scenario, step counts were estimated using a previously published step-counting method for smartphones that uses raw sub-second level accelerometer data. We calculated mean bias and limits of agreement (LoA) between step count estimates and validation criteria using Bland-Altman analysis.

Results

In the internal validation datasets, participants performed 751.7±581.2 (mean±SD) steps, and the mean bias was -7.2 steps (LoA -47.6, 33.3) or -0.5%. In the manual validation datasets, the ground truth step count was 367.4±359.4 steps while the mean bias was -0.4 steps (LoA -75.2, 74.3) or 0.1 %. In the wearable validation dataset, Fitbit devices indicated mean step counts of 1931.2±2338.4, while the calculated bias was equal to -67.1 steps (LoA -603.8, 469.7) or a difference of 0.3 %.

Conclusions

This study demonstrates that our open-source step counting method for smartphone data provides reliable step counts across sensor locations, measurement scenarios, and populations, including healthy adults and patients with cancer.

Phase II Trials of Iniparib (BSI-201) in Combination with Gemcitabine and Carboplatin in Patients with Recurrent Ovarian Cancer

BACKGROUND

Iniparib (BSI-201), a novel anticancer agent thought to have poly(ADP-ribose) polymerase (PARP) inhibitory activity and synergy with both gemcitabine and carboplatin (GC) was evaluated in 2 cohorts with GC.

METHODS

Parallel multicenter, single-arm, phase II studies using a Simon two-stage design. Eligible patients had a histological diagnosis of epithelial ovarian carcinoma, fallopian tube cancer, or primary peritoneal carcinoma and demonstration of platinum-sensitive (≥6 months [mo]) or -resistant disease (relapse 2-6 mo post-platinum). Carboplatin (AUC 4 IV day 1), gemcitabine (1000 mg/m2 IV days 1 and 8), and iniparib (5.6 mg/kg IV days 1, 4, 8, and 11) were given on a 21-day cycle.

RESULTS

The overall response rate (ORR RECIST 1.0) in platinum sensitive disease was 66% (95% CI, 49-80) with a higher response rate in the 15 pts with germline BRCA mutations (gBRCAmut) (73%). Median PFS was 9.9 (95% CI, 8.2-11.3) months. In the platinum resistant population the ORR was 26% (95% CI, 14-42), however in the 11 pts for whom BRCA mutation was present, the best overall response was PR in 5 (46%). Median PFS was 6.8 months (range, 5.7-7.7 months). Notably, among the 17 CA-125-response-evaluable patients who did not achieve tumor response, 7 (41.2%) patients had a CA125 response, and 93% has clinical benefit (CR + PR + SD). The GCI combination was generally well tolerated despite a high incidence of thrombocytopenia and neutropenia, with no new toxicities.

CONCLUSIONS

Given the subsequent lack of efficacy demonstrated for iniparib in breast cancer, these are studies of GC and demonstrate a higher than traditionally appreciated activity in patients with platinum-sensitive and -resistant recurrent ovarian cancer, especially in patients that harbor a BRCA mutation, resetting the benchmark for efficacy in phase II trials. (ClinicalTrials.gov Identifiers: NCT01033292 & NCT01033123).

Ultrasensitive detection of circulating LINE-1 ORF1p as a specific multi-cancer biomarker

Improved biomarkers are needed for early cancer detection, risk stratification, treatment selection, and monitoring treatment response. While proteins can be useful blood-based biomarkers, many have limited sensitivity or specificity for these applications. Long INterspersed Element-1 (LINE-1, L1) open reading frame 1 protein (ORF1p) is a transposable element protein overexpressed in carcinomas and high-risk precursors during carcinogenesis with negligible detectable expression in corresponding normal tissues, suggesting ORF1p could be a highly specific cancer biomarker. To explore the potential of ORF1p as a blood-based biomarker, we engineered ultrasensitive digital immunoassays that detect mid-attomolar (10-17 M) ORF1p concentrations in patient plasma samples across multiple cancers with high specificity. Plasma ORF1p shows promise for early detection of ovarian cancer, improves diagnostic performance in a multi-analyte panel, and provides early therapeutic response monitoring in gastric and esophageal cancers. Together, these observations nominate ORF1p as a multi-cancer biomarker with potential utility for disease detection and monitoring.

Safety and efficacy of mirvetuximab soravtansine, a folate receptor alpha (FRα)-targeting antibody-drug conjugate (ADC), in combination with bevacizumab in patients with platinum-resistant ovarian cancer

PURPOSE

Evaluate the antitumor activity and safety profile of the combination of mirvetuximab soravtansine and bevacizumab in patients with platinum-resistant ovarian cancer.

METHODS

Patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer, whose most recent platinum-free interval was ≤6 months, were administered mirvetuximab soravtansine (6 mg/kg adjusted ideal body weight) and bevacizumab (15 mg/kg), intravenously, once every 3 weeks. Eligibility included FRα expression by immunohistochemistry (IHC; ≥25% of cells with ≥2+ intensity). Prior bevacizumab and/or PARP inhibitor (PARPi) treatment were permitted. The primary endpoint was confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and safety.

RESULTS

Ninety-four patients received combination treatment with mirvetuximab soravtansine and bevacizumab. Median age was 62 years (range, 39-81). Fifty-two percent had ≥3 prior therapies; 59% had prior bevacizumab; and 27% had prior PARPi. ORR was 44% (95% CI 33, 54) with 5 complete responses, median DOR 9.7 months (95% CI 6.9, 14.1), and median PFS 8.2 months (95% CI 6.8, 10.0). Treatment-related adverse events were consistent with the profiles of each agent, with the most common being blurred vision (all grades 57%; grade 3, 1%), diarrhea (54%; grade 3, 1%), and nausea (51%; grade 3, 1%).

CONCLUSION

The mirvetuximab soravtansine plus bevacizumab doublet is an active and well-tolerated regimen in patients with FRα-expressing platinum-resistant ovarian cancer. Promising activity was observed for patients regardless of level of FRα expression or prior bevacizumab. These data underscore the potential for mirvetuximab soravtansine as the combination partner of choice for bevacizumab in this setting.

Safety and management of niraparib monotherapy in ovarian cancer clinical trials

Niraparib is a poly (ADP-ribose) polymerase inhibitor that has shown a significant improvement in progression-free survival irrespective of biomarker status in patients with advanced epithelial ovarian cancer. This review focuses on the adverse events associated with niraparib and their management to maintain efficacy of niraparib treatment and improve quality of life for patients. In five trials assessing efficacy of niraparib in patients with advanced epithelial ovarian cancer (PRIMA, NOVA, NORA, QUADRA, and PRIME), treatment-emergent adverse events of any grade were reported in nearly all patients (≥99%) receiving niraparib; the events were grade ≥3 in 51-74% of patients. Across all lines of therapy, treatment-emergent adverse events led to dose interruptions in 62-80% of patients receiving niraparib and dose reductions in 47-71%. Hematologic events were most frequently reported, including thrombocytopenia, anemia, and neutropenia. Common non-hematologic events included gastrointestinal events, which were generally low grade (<5% were grade ≥3). Clinical strategies to manage these and other events, such as fatigue and insomnia, cognitive behavioral therapy and pharmacologic agents, are summarized. Once-daily niraparib dosing may be advantageous for some patients for many reasons, including night-time dosing which may help alleviate gastrointestinal symptoms. An individualized starting dose (determined by baseline body weight and platelet count) of niraparib demonstrated an improved safety profile while maintaining efficacy. Patients receiving the niraparib individualized starting dose had fewer grade ≥3 adverse events, dose interruptions, and dose reductions than patients receiving a fixed starting dose. The safety profile of niraparib across five pivotal studies in advanced epithelial ovarian cancer was consistent across multiple lines of treatment, including as maintenance therapy in first-line and recurrent settings and as treatment in heavily pre-treated patients. Long-term safety data from the NOVA trial confirmed that, with appropriate and early dose modifications, niraparib is well tolerated.

Molecular Landscape of Mullerian Clear Cell Carcinomas Identifies The Cancer Genome Atlas-like Prognostic Subgroups

Mullerian clear cell carcinoma (CCC) is often aggressive and chemoresistant. The prognostic significance of molecular subclassification of endometrioid carcinomas is well established. However, less is known about the molecular landscape of CCC. The aim of this study was to better characterize the genetic landscape of a large cohort of CCC and correlate these findings with clinicopathologic features. CCC of the ovary (n = 72), endometrium (n = 24), and peritoneum/abdominal wall (n = 5) were retrospectively identified. Tumors had undergone tumor-only targeted sequencing using a hybrid capture next-generation sequencing panel. Median tumor mutational burden was 6.8 mutations/megabase (range, 1.3-185, 21% were ≥10 mutations/Mb). The most frequently mutated genes were ARID1A (48%), PIK3CA (45%), TP53 (23%), and PTEN (10%). ERBB2 amplification occurred in 4%. When classified according to the Cancer Genome Atlas/the Proactive Molecular Risk Classifier for Endometrial Cancer endometrial carcinoma molecular subgroups, 3 (3%) were POLE ultramutated, 5 (5%) were microsatellite instability-high (MSI-H), 20 (20%) were TP53-mutant subgroup, and 73 (72%) were no specific molecular profile (NSMP). Immunohistochemical expression of estrogen receptor, progesterone receptor, and programmed death-ligand 1 were not associated with the molecular subgroup. POLE and MSI-H tumors were characterized by an excellent prognosis, and the TP53-mutant subgroup had a worse disease-free survival than NSMP. NSMP tumors could be further substratified as high-risk NSMP if they lacked PIK3CA, PIK3R1, and ARID1A mutations, and/or harbored a TERT-promoter mutation. The Cancer Genome Atlas and NSMP-specific stratifications were prognostic for both the entire cohort and the subset of stage I ovarian tumors. On multivariable analysis, stage, lymphovascular invasion, and tumor mutational burden were prognostic for disease-free survival, whereas advanced stage and TP53-mutant subgroup - but not a TP53 mutation in isolation - were negative prognostic factors for overall survival. These data suggest that routine molecular profiling of Mullerian CCC may be warranted for both prognosis and identification of potential targeted treatments, such as immunotherapy and anti-HER2 agents.

Efficacy and Safety of Mirvetuximab Soravtansine in Patients With Platinum-Resistant Ovarian Cancer With High Folate Receptor Alpha Expression: Results From the SORAYA Study

PURPOSE

Single-agent chemotherapies have limited activity and considerable toxicity in patients with platinum-resistant epithelial ovarian cancer (PROC). Mirvetuximab soravtansine (MIRV) is an antibody-drug conjugate targeting folate receptor α (FRα). SORAYA is a single-arm, phase II study evaluating efficacy and safety of MIRV in patients with PROC.

METHODS

SORAYA enrolled FRα-high patients with PROC who had received one to three prior therapies, including required bevacizumab. The primary end point was confirmed objective response rate (ORR) by investigator; duration of response was the key secondary end point.

RESULTS

One hundred six patients were enrolled; 105 were evaluable for efficacy. All patients had received prior bevacizumab, 51% had three prior lines of therapy, and 48% received a prior poly ADP-ribose polymerase inhibitor. Median follow-up was 13.4 months. ORR was 32.4% (95% CI, 23.6 to 42.2), including five complete and 29 partial responses. The median duration of response was 6.9 months (95% CI, 5.6 to 9.7). In patients with one to two priors, the ORR by investigator was 35.3% (95% CI, 22.4 to 49.9) and in patients with three priors was 30.2% (95% CI, 18.3 to 44.3). The ORR by investigator was 38.0% (95% CI, 24.7 to 52.8) in patients with prior poly ADP-ribose polymerase inhibitor exposure and 27.5% (95% CI, 15.9 to 41.7) in those without. The most common treatment-related adverse events (all grade and grade 3-4) were blurred vision (41% and 6%), keratopathy (29% and 9%), and nausea (29% and 0%). Treatment-related adverse events led to dose delays, reductions, and discontinuations in 33%, 20%, and 9% of patients, respectively.

CONCLUSION

MIRV demonstrated consistent clinically meaningful antitumor activity and favorable tolerability and safety in patients with FRα-high PROC who had received up to three prior therapies, including bevacizumab, representing an important advance for this biomarker-selected population.

A Phase II, Two-Stage Study of Letrozole and Abemaciclib in Estrogen Receptor-Positive Recurrent Endometrial Cancer

PURPOSE

Estrogen receptor (ER)-positive endometrial cancers (ECs) are characterized by phosphatidylinositol 3-kinase (PI3K) and receptor tyrosine kinase (RTK)/RAS/β-catenin (CTNNB1) pathway alterations in approximately 90% and 80% of cases, respectively. Extensive cross-talk between ER, PI3K, and RTK/RAS/CTNNB1 pathways leads to both ligand-dependent and ligand-independent ER transcriptional activity as well as upregulation of cyclin D1 which, in complex with cyclin-dependent kinases 4 and 6 (CDK4 and CDK6), is a critical regulator of cell cycle progression and a key mediator of resistance to hormonal therapy. We hypothesized that the combination of the aromatase inhibitor letrozole and CDK4/6 inhibitor abemaciclib would demonstrate promising activity in this setting.

METHODS

We conducted a phase II, two-stage study of letrozole/abemaciclib in recurrent ER-positive EC. Eligibility criteria included measurable disease, no limit on prior therapies, and all EC histologies; prior hormonal therapy was allowed. Primary end points were objective response rate by RECIST 1.1 and progression-free survival (PFS) rate at 6 months.

RESULTS

At the data cutoff date (December 03, 2021), 30 patients (28 with endometrioid EC) initiated protocol therapy; 15 (50%) patients had prior hormonal therapy. There were nine total responses (eight confirmed), for an objective response rate of 30% (95% CI, 14.7 to 49.4), all in endometrioid adenocarcinomas. Median PFS was 9.1 months, PFS at 6 months was 55.6% (95% CI, 35.1 to 72), and median duration of response was 7.4 months. Most common ≥ grade 3 treatment-related adverse events were neutropenia (20%) and anemia (17%). Responses were observed regardless of grade, prior hormonal therapy, mismatch repair, and progesterone receptor status. Exploratory tumor profiling revealed several mechanistically relevant candidate predictors of response (CTNNB1, KRAS, and CDKN2A mutations) or absence of response (TP53 mutations), which require independent validation.

CONCLUSION

Letrozole/abemaciclib demonstrated encouraging and durable evidence of activity in recurrent ER positive endometrioid EC.

Mutational Signature 3 Detected from Clinical Panel Sequencing is Associated with Responses to Olaparib in Breast and Ovarian Cancers

PURPOSE

The identification of patients with homologous recombination deficiency (HRD) beyond BRCA1/2 mutations is an urgent task, as they may benefit from PARP inhibitors. We have previously developed a method to detect mutational signature 3 (Sig3), termed SigMA, associated with HRD from clinical panel sequencing data, that is able to reliably detect HRD from the limited sequencing data derived from gene-focused panel sequencing.

EXPERIMENTAL DESIGN

We apply this method to patients from two independent datasets: (i) high-grade serous ovarian cancer and triple-negative breast cancer (TNBC) from a phase Ib trial of the PARP inhibitor olaparib in combination with the PI3K inhibitor buparlisib (BKM120; NCT01623349), and (ii) TNBC patients who received neoadjuvant olaparib in the phase II PETREMAC trial (NCT02624973).

RESULTS

We find that Sig3 as detected by SigMA is positively associated with improved progression-free survival and objective responses. In addition, comparison of Sig3 detection in panel and exome-sequencing data from the same patient samples demonstrated highly concordant results and superior performance in comparison with the genomic instability score.

CONCLUSIONS

Our analyses demonstrate that HRD can be detected reliably from panel-sequencing data that are obtained as part of routine clinical care, and that this approach can identify patients beyond those with germline BRCA1/2mut who might benefit from PARP inhibitors. Prospective clinical utility testing is warranted.

EPIK-O/ENGOT-OV61: alpelisib plus olaparib vs cytotoxic chemotherapy in high-grade serous ovarian cancer (phase III study)

Patients with platinum-resistant or -refractory high-grade serous ovarian cancer (HGSOC) have a poor prognosis, and their management represents a substantial unmet medical need. Preclinical data and results from a phase Ib trial demonstrated the efficacy and tolerability of the combination of the α-specific phosphatidylinositol-3-kinase (PI3K) inhibitor alpelisib plus the poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor olaparib in platinum-resistant, non-BRCA-mutated ovarian cancer. Here, we describe the study design and rationale for the phase III, multicenter, open-label, randomized, active-controlled EPIK-O/ENGOT-OV61 trial investigating alpelisib in combination with olaparib compared with standard-of-care chemotherapy in patients with platinum-resistant or -refractory HGSOC with no germline BRCA mutation. Progression-free survival (blinded independent review committee) is the primary end point. Overall survival is a key secondary end point. Clinical Trial Registration:: NCT04729387 (ClinicalTrials.gov).

Satellite repeat RNA expression in epithelial ovarian cancer associates with a tumor-immunosuppressive phenotype

Aberrant expression of viral-like repeat elements is a common feature of epithelial cancers, and the substantial diversity of repeat species provides a distinct view of the cancer transcriptome. Repeatome profiling across ovarian, pancreatic, and colorectal cell lines identifies distinct clustering independent of tissue origin that is seen with coding gene analysis. Deeper analysis of ovarian cancer cell lines demonstrated that human satellite II (HSATII) satellite repeat expression was highly associated with epithelial-mesenchymal transition (EMT) and anticorrelated with IFN-response genes indicative of a more aggressive phenotype. SATII expression - and its correlation with EMT and anticorrelation with IFN-response genes - was also found in ovarian cancer RNA-Seq data and was associated with significantly shorter survival in a second independent cohort of patients with ovarian cancer. Repeat RNAs were enriched in tumor-derived extracellular vesicles capable of stimulating monocyte-derived macrophages, demonstrating a mechanism that alters the tumor microenvironment with these viral-like sequences. Targeting of HSATII with antisense locked nucleic acids stimulated IFN response and induced MHC I expression in ovarian cancer cell lines, highlighting a potential strategy of modulating the repeatome to reestablish antitumor cell immune surveillance.

Improved T-cell Immunity Following Neoadjuvant Chemotherapy in Ovarian Cancer

PURPOSE

Although local tissue-based immune responses are critical for elucidating direct tumor-immune cell interactions, peripheral immune responses are increasingly recognized as occupying an important role in anticancer immunity. We evaluated serial blood samples from patients with advanced epithelial ovarian cancer (EOC) undergoing standard-of-care neoadjuvant carboplatin and paclitaxel chemotherapy (including dexamethasone for prophylaxis of paclitaxel-associated hypersensitivity reactions) to characterize the evolution of the peripheral immune cell function and composition across the course of therapy.

EXPERIMENTAL DESIGN

Serial blood samples from 10 patients with advanced high-grade serous ovarian cancer treated with neoadjuvant chemotherapy (NACT) were collected before the initiation of chemotherapy, after the third and sixth cycles, and approximately 2 months after completion of chemotherapy. T-cell function was evaluated using ex vivo IFNγ ELISpot assays, and the dynamics of T-cell repertoire and immune cell composition were assessed using bulk and single-cell RNA sequencing (RNAseq).

RESULTS

T cells exhibited an improved response to viral antigens after NACT, which paralleled the decrease in CA125 levels. Single-cell analysis revealed increased numbers of memory T-cell receptor (TCR) clonotypes and increased central memory CD8+ and regulatory T cells throughout chemotherapy. Finally, administration of NACT was associated with increased monocyte frequency and expression of HLA class II and antigen presentation genes; single-cell RNAseq analyses showed that although driven largely by classical monocytes, increased class II gene expression was a feature observed across monocyte subpopulations after chemotherapy.

CONCLUSIONS

NACT may alleviate tumor-associated immunosuppression by reducing tumor burden and may enhance antigen processing and presentation. These findings have implications for the successful combinatorial applications of immune checkpoint blockade and therapeutic vaccine approaches in EOC.

Evaluation of Treatment With Talazoparib and Avelumab in Patients With Recurrent Mismatch Repair Proficient Endometrial Cancer

Question

Is treatment with combined polyadenosine diphosphate-ribose polymerase and immune checkpoint inhibition active and safe in patients with recurrent mismatch repair proficient endometrial cancer (MMRP EC)?

Findings

In this single-arm, phase 2, 2-stage, nonrandomized clinical trial of treatment with avelumab and talazoparib in recurrent MMRP EC that included 35 patients, the confirmed objective response rate was 11.4%, and the progression-free survival at 6 months rate was 22.9%. No patients discontinued therapy because of toxic effects, and immunogenomic profiling provided insights into subsets of patients who may derive benefit from this combination.

Meaning

These study findings suggest that treatment with avelumab and talazoparib has a favorable toxic effects profile and support further investigation in certain subsets of patients with recurrent MMRP EC.

Importance

Although the activity of pembrolizumab and lenvatinib (the only US Food and Drug Administration–approved immunotherapy for mismatch repair proficient endometrial cancer [MMRP EC]) is compelling, there are no biomarkers of response and most patients do not tolerate, do not respond to, or develop resistance to this regimen, highlighting the need for additional, potentially biomarker-driven therapeutic approaches for patients with recurrent MMRP EC.

Objective

To assess the potential positive outcomes and safety of the combination of the polyadenosine diphosphate-ribose polymerase inhibitor talazoparib and the programmed cell death ligand 1 (PD-L1) inhibitor avelumab in recurrent MMRP EC.

Design, Settings, and Participants

This investigator-initiated, open-label, single-arm, 2-stage, phase 2 study nonrandomized controlled trial patients at 4 institutions in the US. Key eligibility criteria included measurable disease, unlimited prior therapies, and all endometrial cancer histologies.

Interventions

Talazoparib, 1 mg, orally, daily, and avelumab, 10 mg/kg, intravenously, every 2 weeks, were administered until disease progression or unacceptable toxic effects.

Main Outcomes and Measures

Statistical considerations were developed for 2 coprimary objectives of objective response rate and rate of progression-free survival at 6 months, with a 2-stage design that allowed for early discontinuation for futility. Prespecified exploratory objectives included the association of immunogenomic features (determined by targeted-panel next-generation sequencing and immunohistochemistry) with activity.

Results

Thirty-five female patients (mean [SD] age, 67.9 [8.41] years) received protocol therapy; 9 (25.7%) derived clinical benefit after meeting at least 1 of the 2 coprimary end points. Four patients (11.4%) exhibited confirmed objective response rates (4 partial responses), and 8 (22.9%) survived progression free at 6 months. The most common grade 3 and 4 treatment-related toxic effects were anemia (16 [46%]), thrombocytopenia (10 [29%]), and neutropenia (4 [11%]); no patient discontinued receipt of therapy because of toxic effects. Tumors with homologous recombination repair alterations were associated with clinical benefit from treatment with avelumab and talazoparib. Tumor mutational burden, tumor-infiltrating lymphocytes, and PD-L1 status were not associated with clinical benefit.

Conclusions and Relevance

The results of this nonrandomized controlled trial suggest that treatment with avelumab and talazoparib demonstrated a favorable toxic effect profile and met the predetermined criteria to be considered worthy of further evaluation in MMRP EC. Immunogenomic profiling provided insights that may inform ongoing and future studies of polyadenosine diphosphate-ribose polymerase and PD-L1 inhibitor combinations in endometrial cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT02912572

Niraparib treatment for patients with BRCA-mutated ovarian cancer: review of clinical data and therapeutic context

We reviewed clinical data for niraparib monotherapy in BRCA-mutated (BRCAm) epithelial ovarian cancer (OC), contextualizing results with data from other poly(ADP-ribose) polymerase inhibitors (PARPis). Niraparib reduced the likelihood of progression or death by 60% as first-line maintenance therapy and by 73-78% in recurrent disease. In heavily pretreated OC, efficacy was greater in the BRCAm versus non-BRCAm cohort. Quality-of-life (QoL) was maintained throughout treatment. Adverse events were consistent with the known niraparib safety profile. Cumulative efficacy, safety and QoL evidence demonstrate niraparib maintenance monotherapy has a positive benefit:risk ratio in BRCAm OC. Niraparib significantly improved progression-free survival as first-line maintenance therapy in all patients with OC (i.e., of any biomarker status).

Abstract 3065: Establishment and characterization of a platform of endometrial cancer organoids

Background: Endometrial cancer is the most commonly diagnosed gynecologic cancer in the US; the incidence is rising, and survival rates for this cancer are decreasing. There is a paucity of effective treatment for recurrent endometrial cancer, especially high grade endometrial cancers (HGEC) which include serous, carcinosarcoma, endometrioid, and clear cell histologies. Models that mimic the clinical and molecular characteristics of HGEC are lacking. To support the development of next generation therapeutics for endometrial cancer, we report on the establishment of 3D endometrial patient-derived organoids (PDOs) from HGEC.

Methods: 26 Tumors from 21 different patients with HGEC (Serous, Carcinosarcoma, Clear Cell and High-grade Endometrioid subtypes) who underwent surgical resection (n= 13), biopsy (n = 7), paracentesis (n = 3) or thoracentesis (n = 3) were passaged as 3D organoid cultures in Matrigel in an optimized media. Robust models (defined by average days to passage &lt;14 days) were viably banked. 3 frozen models were also thawed and re-cultured to assess the viability post freezing. PDOs were collected for H&E staining and their histology was compared to the original diagnosis. DNA replication rate and the effect of replication stress on organoid growth were assessed by the DNA Fiber Assay and immunofluorescence (IF). Finally, an established clear cell endometrial cancer organoid model was engrafted in mice to generate a Patient-Derived Xenograft (PDX) model.

Results: Endometrial PDOs were successfully developed from 19 of 26 original samples for an overall success rate of 73.1%. Successful PDOs were developed from multiple histologies, including 8 carcinosarcoma, 6 uterine serous, 2 endometrioid, 2 clear cell and 1 mixed uterine serous and endometrioid. Though biopsy samples had initially fewer viable cells, our overall success rate was similar at 85.7% compared to 84.6% for surgical resections and higher than 66.7% for paracenteses. Samples obtained via thoracentesis did not form PDOs. Endometrial PDOs were histologically validated to match the primary patient tumor. Freeze thawing had no effect on morphology and growth characteristics. DNA fiber assays could be successfully conducted in PDOs, with a reduction in replication rate observed in PDO models treated with ATR or WEE1 inhibitors, with concurrent increase in y-H2AX and decrease in pRPA2 observed by IF. We also successfully generated a validated PDX model from organoids. Studies to determine molecular fidelity between the original patient tumor and established organoids are ongoing.

Conclusions: We describe the successful establishment of 19 endometrial PDO models which retain original tumor morphology and demonstrate sensitivity to drug-induced DNA damage. 3D endometrial organoids can therefore be used for further target discovery and validation as well as biomarker studies to advance targeted therapies for high-grade endometrial cancer.

Citation Format: Aisha L. Saldanha, Ha V. Vo, Kevin Vasquez, Kenneth Ngo, Shrabasti Roychoudhury, Carina Feeney, Courtney H. Qi, Swati Narayan, Jennifer D. Curtis, Prafulla C. Gokhale, Dipanjan Chowdhury, Cloud P. Paweletz, Marisa R. Nucci, Ursula A. Matulonis, Elena Ivanova, Joyce F. Liu. Establishment and characterization of a platform of endometrial cancer organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3065.

Overall survival data from a 3-arm, randomized, open-label, phase 2 study of relacorilant, a selective glucocorticoid receptor modulator, combined with nab-paclitaxel in patients with recurrent platinum-resistant ovarian cancer

LBA5503

Background: Cortisol contributes to chemotherapy resistance by suppressing apoptotic pathways that cytotoxic agents utilize. Preclinical and clinical data indicate that glucocorticoid receptor (GR) modulation with relacorilant (RELA) reverses the anti-apoptotic effects of cortisol and restores the efficacy of cytotoxic agents. We report overall survival (OS) results from a randomized, controlled phase 2 study of RELA + nab-paclitaxel (NP) compared to NP only in patients with ovarian cancer (NCT03776812). The primary analysis showed improved progression-free survival (PFS) and a favorable safety profile with intermittent RELA + NP vs NP only, despite overrepresentation of primary platinum-refractory patients in the intermittent RELA + NP (n = 7) vs the NP-only arm (n = 1). Methods: A phase 2, open-label, randomized, 3-arm study of 2 RELA dosing schedules + NP compared with NP only was performed. 178 women with recurrent, platinum-resistant/refractory, high-grade serous or endometrioid epithelial ovarian, primary peritoneal, or fallopian tube cancer or ovarian carcinosarcoma with ≤4 prior chemotherapeutic regimens were enrolled. Patients were randomized 1:1:1 to: a) NP (80 mg/m2) + intermittent RELA (150 mg QD the day before, of, and after NP) (n = 60); b) NP (80 mg/m2) + continuous RELA (100 mg QD) (n = 58); or c) NP only (100 mg/m2) (n = 60). NP was administered on days 1, 8, and 15 of each 28-day cycle. The primary endpoint was PFS; OS was a secondary endpoint. OS data for the intermittent and continuous arms were compared to NP only using a 2-sided log-rank test, stratified by presence of ascites and relapse within 6 months on previous taxane, at a 0.05 level of significance without multiplicity adjustment. Results: At the pre-defined OS analysis (128 OS events), hazard ratios (HRs) were 0.67 (95% CI [0.43, 1.03], P= 0.066) and 0.85 (95% CI [0.56, 1.29], P= 0.447) for intermittent and continuous RELA + NP vs NP only. Median OS was 13.9 (95% CI [11.1, 18.4]), 11.3 (95% CI [7.5, 16.4]), and 12.2 (95% CI [7.7, 15.3]) months in the intermittent RELA + NP, continuous RELA + NP, and NP-only arms. In the subgroup of patients without primary platinum-refractory disease, a statistically significant improvement in OS was observed with HR 0.63 (95% CI [0.39, 0.99], P= 0.045) and median OS of 13.9 (95% CI [11.1, 18.4]) vs 12.2 (95% CI [7.7, 15.3]) months for intermittent RELA + NP vs NP only. Conclusions: In addition to the improved PFS and DOR observed at the primary analysis, the OS analysis confirmed the survival benefit of intermittent RELA + NP compared to NP only, particularly in patients who were not primary platinum refractory. A phase 3 trial evaluating intermittent RELA + NP vs investigator’s choice of chemotherapy in patients without primary platinum-refractory disease is ongoing (NCT05257408). Clinical trial information: NCT03776812.

Stage 1 results of BrUOG 354: A randomized phase II trial of nivolumab alone or in combination with ipilimumab for people with ovarian and other extra-renal clear cell carcinomas (NCT03355976)

5598

Background: Clear Cell Carcinoma (CCC) outside the kidney is a rare tumor that can arise from multiple organs, including the ovary, endometrium and cervix. Extra-renal CCC is chemoresistant and has a poor prognosis. Data suggest that CCC of the gynecologic tract resembles the genomic profile of Renal Cell Carcinoma (RCC), which is responsive to immune checkpoint inhibition (ICI) therapy. We are conducting a two-stage phase 2 trial evaluating immunotherapy for extra-renal CCC. The primary objective is to assess overall rate of response (ORR); Progression-Free (PFS), Overall Survival (OS), and correlative biomarker studies are secondary. Here we present the results of Stage 1. Methods: This is a randomized two-stage non-comparative phase II study evaluating nivolumab (240mg IV every two weeks) alone (N) and in combination with ipilimumab (1mg/kg every six weeks, [N+I]) in patients with relapsed extra-renal CCC after at least one prior chemotherapy (no prior ICI), and measurable disease. Treatment was continued until disease progression or unacceptable toxicity. Stage 1 of this trial called for up to 30 volunteers (15 per arm) after which the study was closed. Consideration to reopen to stage 2 called for two or more responses in either arm. Here we present the completion of Stage 1; the release of results was approved by Brown University Oncology Group (BrUOG) Data Safety and Monitoring Committee. Results: Between July 2018 and October 2021, 30 patients were enrolled and 29 were treated (Table). The majority (83%) had CCC of the ovary (n=24). The ORR with N and N+I was 14.2 and 26.7%, respectively. The 6 month PFS rate was 19.1 and 43.8%; median PFS was 2.7 (95%CI 1.3-5.1) and 5.1 months (95%CI 0.9-NR), respectively. Grade ≥3 treatment-related toxicities occurred in 4 (28.6%) on N and 5 (33.3%) on N+I. There were no treatment-related deaths and no new safety signals. One volunteer enrolled on N+I stopped treatment after two years and remains in CR to date. Conclusions: Although sufficient activity was seen in CCC in both arms, the single-agent activity of N is similar to published reports in platinum-resistant epithelial ovarian cancer and decision made not to pursue it further. However, the combination of ipilimumab and nivolumab warrants additional investigation, and the second stage of this study will enroll 14 more patients to receive N+I. Clinical trial information: NCT03355976. [Table: see text]

A first-in-human phase 1 dose escalation study of FF-10850 (liposomal topotecan) in patients with advanced solid tumors

3101

Background: FF-10850 (liposomal topotecan) was developed using a unique dihydrosphingomyelin-based carrier to enhance tumor drug delivery and retention, leading to improved efficacy and safety. Preclinical studies demonstrated superior anti-tumor activity with less myelosuppression compared to topotecan, with a pharmacokinetic (PK) profile supporting a twice-monthly dosing schedule. Methods: Accelerated titration followed by a 3+3 dose escalation design was used to determine the safety, maximum tolerated dose (MTD), dose-limiting toxicities (DLT), PK, and recommended Phase 2 dose. FF-10850 was administered IV on Day 1 and 15 of a 28-day cycle until disease progression or unacceptable toxicity. Results: Patients (pts) [n = 29; 4M/25F; median age, 64 (range, 37–79) and # prior therapies, 4 (range, 1–8)] received FF-10850 at doses of 1, 2, 2.5, 3, 3.5 and 5 mg/m2; median # of cycles, 2 (range, 1–11). FF-10850 was well-tolerated at doses up to 2 mg/m2. Common drug-related adverse events (AEs) included anemia (83%, 51% Gr≥3), thrombocytopenia (62%, 35% Gr≥3), neutropenia (59%, 45% Gr≥3), nausea (38%), fatigue (24%, 7% Gr≥3), alopecia (24%), and hypokalemia (17%, 3% Gr≥3). Dose-limiting Gr≥3 thrombocytopenia, neutropenia, anemia, and fatigue were observed at doses ≥2.5 mg/m2. Eight pts required dose reductions due to AEs. The median time on study was 8.3 (1.6–45) weeks, with a median PFS of 9.4 weeks and median OS at least 26 weeks. Of 24 pts evaluable for response, two achieved a partial response (PR). One pt with ovarian cancer treated at 3.5 mg/m2 achieved a complete response in target lesions by Cycle 2 with stable non-target lesions, and maintained response for > 30 weeks (8 cycles) before progressing; dose was reduced in this pt to 2.6 mg/m2 at Cycle 2 due to Gr 4 thrombocytopenia. Another pt with refractory metastatic Merkel cell carcinoma tolerated therapy well at 2 mg/m2 and achieved a 48% reduction in target lesions that was maintained for > 30 weeks (8 cycles). Stable disease was observed in an additional 9 pts for ≥10 weeks (5 ovarian, 2 uterine and 2 cervical); five who maintained disease control for ≥24-45 weeks including one (ovarian) who had previously progressed on topotecan. An extended plasma t1/2 for topotecan of 25-30 hours was observed with no apparent dose-dependency or accumulation; < 1% of circulating topotecan was in the free (released) form. Conclusions: FF-10850 was well-tolerated up to 2 mg/m2 with anti-tumor activity demonstrated in heavily pre-treated pts with solid tumors including ovarian cancer, and an improved PK profile allowing less frequent dosing compared to topotecan. Expansion is ongoing in pts with ovarian and Merkel cell carcinoma at the RP2D of 2 mg/m2 IV on Day 1 & 15 of a 28-day cycle. Clinical trial information: NCT04047251.

Mirvetuximab soravtansine (MIRV) in patients with platinum-resistant ovarian cancer with high folate receptor alpha (FRα) expression: Characterization of antitumor activity in the SORAYA study

5512

Background: SORAYA is a global single arm phase 3 study evaluating MIRV in patients (pts) with FRα high platinum-resistant ovarian cancer (PROC). MIRV is an antibody drug conjugate comprising a FRα-binding antibody, cleavable linker, and maytansinoid DM4, a potent tubulin-targeting agent. In this study, MIRV demonstrated activity in a broad population of PROC, regardless of number of prior lines of therapy or prior PARPi (Matulonis, SGO 2022). Here we describe details of response to treatment important for clinical decision making. Methods: SORAYA enrolled PROC pts with high FRα expression by immunohistochemistry (Roche FOLR1 Assay ≥ 75% of cells with PS2+ staining intensity) who had received 1-3 prior therapies, including required prior bevacizumab. Pts received intravenous MIRV at 6 mg/kg, adjusted ideal body weight, on Day 1 of a 21-day cycle until disease progression or unacceptable toxicity. The primary endpoint was confirmed objective response rate (ORR) per RECIST v1.1 by investigator (INV) and the key secondary endpoint was duration of response (DOR); additional endpoints included time to response, CA-125 response, safety and tolerability. Results: 106 pts were enrolled; 51% had 3 prior lines; 48% had 1-2 prior lines of therapy; 48% received prior PARPi. ORR by INV was 32.4% (95% confidence interval [CI]: 23.6%, 42.2%), including five complete responses. Median time to response was 1.5 mos (range 1.0 to 5.6) and 71% of pts demonstrated tumor reduction. At the time of the protocol specified primary analysis (16 Nov 2021), the median DOR was 5.9 mos (95% CI: 5.6, 7.7). With 15 responders remaining on MIRV, the DOR continues to evolve. In the 86 response-evaluable patients for CA-125 (by Gynecologic Cancer Intergroup criteria), responses were observed in 46.5% (95% CI: 35.7, 57.6). Updated data will be presented including depth and duration of responses and impact of dose modifications. The most common treatment-related adverse events (TRAE; all grade, grade 3+) included blurred vision (41%, 6%), keratopathy (36%, 9%), and nausea (29%, 0%). TRAEs led to dose delays in 32%, dose reductions in 19%, and discontinuations in 7% of pts; one patient discontinued treatment due to an ocular event. The tolerability profile of MIRV consists of low-grade, reversible ocular and GI events, managed with dose modifications and supportive care. Conclusions: Treatment options for pts with PROC are limited. MIRV is the first biomarker-directed therapy demonstrating anti-tumor activity in pts with FRα high PROC. These results support the clinically meaningful impact MIRV has for pts with FRα high PROC, irrespective of prior therapies or dose modifications. Clinical trial information: NCT04209855.

Integrated safety summary of single-agent mirvetuximab soravtansine in patients with folate receptor α (FRα)-positive recurrent ovarian cancer: Phase 1 and 3 clinical trials

5574

Background: Available chemotherapies for platinum-resistant ovarian cancer (PROC) have limited clinical activity and considerable toxicity. Mirvetuximab soravtansine (MIRV) is a first-in-class antibody drug conjugate (ADC) comprising a folate receptor alpha (FRα)-binding antibody, cleavable linker, and the maytansinoid payload DM4, a potent tubulin-targeting agent that has demonstrated significant anti-tumor activity in this difficult to treat population. The objective is to characterize the tolerability profile of MIRV in a pooled analysis of experience when administered as monotherapy in patients (pts) with FRα positive recurrent ovarian cancer. Methods: Retrospective pooled analysis included pts enrolled across three studies: phase 1 first-in-human, phase 3 FORWARD I, and phase 3 SORAYA. Analysis included pts with FRα positive recurrent ovarian cancer and those pts with low, medium, and high FRα expression by immunohistochemistry (Roche FOLR1 Assay ≥ 25% of cells with PS2+ staining intensity). All pts received intravenous MIRV at 6 mg/kg, adjusted ideal body weight, on Day 1 of a 21-day cycle until disease progression or unacceptable toxicity. Results: 464 pts were included from 15 countries, with key characteristics: median age 63 yrs, 87% 1-3 prior therapies, 91% platinum free interval ≤6 months, 65% prior bevacizumab, and 25% prior PARPi. The most common treatment-related adverse events (TRAE) (all grade, grade 3+) included blurred vision (42%, 3%), nausea (40%, 2%), diarrhea (33%, 2%), fatigue (31%, 2%), keratopathy (26%, 3%), and dry eye (22%, 1%). TRAEs leading to a dose delay or reduction occurred in 33% and 21% of pts, respectively. Seven % discontinued due to a TRAE. Four pts ( < 1%) discontinued MIRV due to an ocular event. Ninety % of pts with a grade 2+ blurred vision resolved to grade 0 or 1, 93% of pts with grade 2+ keratopathy resolved to grade 0 or 1. No corneal ulcers or perforation have been reported and no patient with a serious ocular event has been reported to have permanent sequelae. Conclusions: In a pooled analysis of 464 patients, MIRV monotherapy has a differentiated and predictable safety profile consisting primarily of low grade and reversible gastrointestinal and ocular events. These events were managed with supportive care and dose modifications if needed, with a low rate of treatment-related discontinuation. The safety profile of MIRV in recurrent ovarian cancer along with the anti-tumor activity in PROC (32.4% ORR Matulonis SGO 2022) support a favorable benefit/risk in this population. Clinical trial information: NCT01609556, NCT04296890, NCT02631876.

STING agonism reprograms tumor-associated macrophages and overcomes resistance to PARP inhibition in BRCA1-deficient models of breast cancer

PARP inhibitors (PARPi) have drastically changed the treatment landscape of advanced ovarian tumors with BRCA mutations. However, the impact of this class of inhibitors in patients with advanced BRCA-mutant breast cancer is relatively modest. Using a syngeneic genetically-engineered mouse model of breast tumor driven by Brca1 deficiency, we show that tumor-associated macrophages (TAMs) blunt PARPi efficacy both in vivo and in vitro. Mechanistically, BRCA1-deficient breast tumor cells induce pro-tumor polarization of TAMs, which in turn suppress PARPi-elicited DNA damage in tumor cells, leading to reduced production of dsDNA fragments and synthetic lethality, hence impairing STING-dependent anti-tumor immunity. STING agonists reprogram M2-like pro-tumor macrophages into an M1-like anti-tumor state in a macrophage STING-dependent manner. Systemic administration of a STING agonist breaches multiple layers of tumor cell-mediated suppression of immune cells, and synergizes with PARPi to suppress tumor growth. The therapeutic benefits of this combination require host STING and are mediated by a type I IFN response and CD8+ T cells, but do not rely on tumor cell-intrinsic STING. Our data illustrate the importance of targeting innate immune suppression to facilitate PARPi-mediated engagement of anti-tumor immunity in breast cancer.

Immunotherapy for ovarian cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, with poor survival rates among patients who have advanced disease despite recent significant advances in therapy, including therapy targeting the homologous recombination pathway. Evidence that cell-mediated antitumor immunity, as well as documented programmed death ligand 1 expression, is correlated with improved survival in EOC garnered early optimism regarding the utility of immune checkpoint blockade (ICB) in ovarian cancer. However, the results of multiple clinical trials investigating ICB have revealed very low levels of activity of single-agent immune checkpoint inhibitors, and the testing of combination therapies has not yet identified any combinations with robust activity in a significant proportion of patients who have EOC. In this review, we summarize the results of the major studies of ICB monotherapy and combinations; review novel combinations under investigation, including ICB with cellular therapies; and discuss potential candidate biomarkers for improving the selection of patients who may respond to ICB.

Combined PARP and HSP90 inhibition: preclinical and Phase 1 evaluation in patients with advanced solid tumours

PURPOSE

PARP inhibitor resistance may be overcome by combinatorial strategies with agents that disrupt homologous recombination repair (HRR). Multiple HRR pathway components are HSP90 clients, so that HSP90 inhibition leads to abrogation of HRR and sensitisation to PARP inhibition. We performed in vivo preclinical studies of the HSP90 inhibitor onalespib with olaparib and conducted a Phase 1 combination study.

PATIENTS AND METHODS

Tolerability and efficacy studies were performed in patient-derived xenograft(PDX) models of ovarian cancer. Clinical safety, tolerability, steady-state pharmacokinetics and preliminary efficacy of olaparib and onalespib were evaluated using a standard 3 + 3 dose-escalation design.

RESULTS

Olaparib/onalespib exhibited anti-tumour activity against BRCA1-mutated PDX models with acquired PARPi resistance and PDX models with RB-pathway alterations(CDKN2A loss and CCNE1 overexpression). Phase 1 evaluation revealed that dose levels up to olaparib 300 mg/onalespib 40 mg and olaparib 200 mg/onalespib 80 mg were safe without dose-limiting toxicities. Coadministration of olaparib and onalespib did not appear to affect the steady-state pharmacokinetics of either agent. There were no objective responses, but disease stabilisation ≥24 weeks was observed in 7/22 (32%) evaluable patients including patients with BRCA-mutated ovarian cancers and acquired PARPi resistance and patients with tumours harbouring RB-pathway alterations.

CONCLUSIONS

Combining onalespib and olaparib was feasible and demonstrated preliminary evidence of anti-tumour activity.

Olaparib With or Without Cediranib Versus Platinum-Based Chemotherapy in Recurrent Platinum-Sensitive Ovarian Cancer (NRG-GY004): A Randomized, Open-Label, Phase III Trial

PURPOSE

Platinum-based chemotherapy is the standard of care for platinum-sensitive ovarian cancer, but complications from repeated platinum therapy occur. We assessed the activity of two all-oral nonplatinum alternatives, olaparib or olaparib/cediranib, versus platinum-based chemotherapy.

PATIENTS AND METHODS

NRG-GY004 is an open-label, randomized, phase III trial conducted in the United States and Canada. Eligible patients had high-grade serous or endometrioid platinum-sensitive ovarian cancer. Patients were randomly assigned 1:1:1 to platinum-based chemotherapy, olaparib, or olaparib/cediranib. The primary end point was progression-free survival (PFS) in the intention-to-treat population. Secondary end points included activity within germline BRCA-mutated or wild-type subgroups and patient-reported outcomes (PROs).

RESULTS

Between February 04, 2016, and November 13, 2017, 565 eligible patients were randomly assigned. Median PFS was 10.3 (95% CI, 8.7 to 11.2), 8.2 (95% CI, 6.6 to 8.7), and 10.4 (95% CI, 8.5 to 12.5) months with chemotherapy, olaparib, and olaparib/cediranib, respectively. Olaparib/cediranib did not improve PFS versus chemotherapy (hazard ratio [HR] 0.86; 95% CI, 0.66 to 1.10; P = .077). In women with germline BRCA mutation, the PFS HR versus chemotherapy was 0.55 (95% CI, 0.32 to 0.94) for olaparib/cediranib and 0.63 (95% CI, 0.37 to 1.07) for olaparib. In women without a germline BRCA mutation, the PFS HR versus chemotherapy was 0.97 (95% CI, 0.73 to 1.30) for olaparib/cediranib and 1.41 (95% CI, 1.07 to 1.86) for olaparib. Hematologic adverse events occurred more commonly with chemotherapy; however, nonhematologic adverse events were higher with olaparib/cediranib. In 489 patients evaluable for PROs, patients receiving olaparib/cediranib scored on average 1.1 points worse on the NFOSI-DRS-P subscale (97.5% CI, -2.0 to -0.2, P = .0063) versus chemotherapy; no difference between olaparib and chemotherapy was observed.

CONCLUSION

Combination olaparib/cediranib did not improve PFS compared with chemotherapy and resulted in reduced PROs. Notably, in patients with a germline BRCA mutation, both olaparib and olaparib/cediranib had significant clinical activity.

Abstract GS2-09: Tamoxifen instigates uterine cancer development by activating PI3K signaling and supersedes PIK3CA driver mutations

Tamoxifen is widely used in the adjuvant treatment of estrogen receptor–positive (ER+) breast cancer and is an important drug for pre-menopausal women and post-menopausal patients who cannot tolerate aromatase inhibitors. Despite the clear clinical benefit in improving relapse-free and overall survival in these patients, an adverse effect of tamoxifen is a 2- to 7-fold increased risk of uterine cancer (UC) after 2-5 years of treatment. To date, the mechanism of tamoxifen-driven tumorigenesis is not well understood, and preventive approaches are lacking. Here, to molecularly characterize tamoxifen-associated uterine cancers (TA-UCs) and gain insights into their unique evolution, we performed whole-exome sequencing of 21 TA-UCs (discovery cohort) and droplet digital PCR (ddPCR) of an additional 40 TA-UCs (validation cohort) obtained from the ‘Tamoxifen Associated Malignancies: Aspects of Risk’ (TAMARISK) study. In addition, we used in vivo mouse models to: (i) further investigate tamoxifen-activated molecular pathways that may be involved in TA-UC tumorigenesis; and (ii) offer mechanistic insights. Overall, we discovered that TA-UCs were genomically similar to non–TA-UCs from The Cancer Genome Atlas (TCGA) project, with one profound exception: TA-UCs are characterized by a lower-than-expected frequency of mutations in two highly prevalent UC driver genes in the PI3K pathway: PIK3CA (14% [3/21] vs 48% [265/554] in non–TA-UC; P=0.003, Fisher’s exact test; Q=0.02, Benjamini-Hochberg FDR) and PIK3R1 (0%, [0/21] vs 31% [174/554]; P=0.001; Q=0.01). We used ddPCR in the independent TA-UC validation cohort and confirmed the low frequency of mutations in PIK3CA (7.5% [3/40] vs 21% [144/685] in control UCs from the Dana-Farber contribution to the AACR GENIE project; P=0.04). We next performed mouse in vivo studies and demonstrated that tamoxifen activated the PI3K pathway and increased cell proliferation in normal mouse uterine tissue through paracrine and autocrine effects, both of which were abrogated by the PI3K inhibitor alpelisib. Taken together, we describe a distinct and novel pathway of carcinogenesis in which tamoxifen acts as a driver event in the uterus and promotes tumor development in a mutation-independent manner. Indeed, tamoxifen may increase the risk of UC by activating the PI3K pathway, which can substitute for the early acquisition of oncogenic PIK3CA or PIK3R1 mutations observed in non–TA-UC tumors. Furthermore, the ability of a PI3K inhibitor to reduce cell proliferation in our mouse model raises the possibility that downregulating the PI3K pathway may prevent or significantly reduce TA-UC development, offering a potential future therapeutic and prevention strategy for specific high-risk patients undergoing tamoxifen therapy.

Citation Format: Kirsten Kubler, Agostina Nardone, Shankara Anand, Daniel Gorvich, Marjolein Droog, Francisco Hermida-Prado, Tara Akshi, Avery S Feit, Gabriella Cohen, Gwen Dackus, Matthew Pun, Yanan Kuang, Justin Cha, Mendy Miller, William J Gibson, Cloud P Paweletz, Eliezer M Van Allen, Flora E van Leeuwen, Petra Nederlof, Harry Hollema, Quang-Dé Nguyen, Marian JE Mourits, Ignaty Leshchiner, Chip Stewart, Ursula A Matulonis, Wilbert Zwart, Yosef E Maruvka, Gad Getz, Rinath Jeselsohn. Tamoxifen instigates uterine cancer development by activating PI3K signaling and supersedes PIK3CA driver mutations [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 GS2-09.

Phase 1b Clinical Trial with Alpelisib plus Olaparib for Patients with Advanced Triple-Negative Breast Cancer

PURPOSE

We had previously reported on the safety and the recommended phase 2 dose (RP2D) of olaparib in combination with the PI3Kα-specific inhibitor alpelisib in patients with high-grade serous ovarian cancer as studied in a phase 1b trial (NCT01623349). Here we report on the breast cancer cohort from that study.

EXPERIMENTAL DESIGN

Eligible patients had recurrent triple-negative breast cancer (TNBC), or recurrent breast cancer of any subtype with a germline BRCA mutation and were enrolled to a dose escalation or expansion cohort. After definition of the RP2D, secondary end points included safety and objective response rate (ORR). Exploratory analyses were performed using circulating free DNA (cfDNA).

RESULTS

17 patients with TNBC were enrolled with a median of 3 prior lines of chemotherapy. The most common treatment-related grade 3-4 adverse events were hyperglycemia (18%) and rash (12%). The ORR was 18% (23% for patients treated at the RP2D) and 59% had disease control. The median duration of response was 7.4 months. Analysis of cfDNA tumor fractions (TFx) revealed that patients with TFx<15% after completion of the first cycle had a longer progression-free survival compared to those with TFx>15% (6.0 months vs 0.9 months, p=0.0001).

CONCLUSIONS

Alpelisib in combination with olaparib is tolerable in patients with pre-treated TNBC, with evidence of activity in non-BRCA carriers. CfDNA provided important prognostic information. Results highlight potential synergistic use of a PI3Ki to sensitize HR-proficient (BRCA wild-type) TNBC to PARPi and suggest the potential to expand the use of PARPi beyond BRCA-mutant tumors.

Patient reported outcomes for cisplatin and radiation followed by carboplatin/paclitaxel versus carboplatin/paclitaxel for locally advanced endometrial carcinoma: An NRG oncology study

INTRODUCTION

Chemotherapy plus radiation (Cis-RT + CP) did not demonstrate superiority in prolonging relapse-free survival compared to chemotherapy alone in patients with stage III or IVA endometrial carcinoma. The impact of treatment on quality of life (QOL), neurotoxicity (NTX) and psychometric properties of the gastrointestinal (GI) symptoms subscale during treatment and up to 1 year are described herein.

METHODS

QOL assessments were scheduled at baseline, 6 weeks (post completion of RT (Cis-RT + CP) or prior to cycle 3 (CP)), then 18 weeks (end of treatment) and 70 weeks (1 year after the end of treatment) after starting treatment. QOL instruments included the FACT-En TOI, FACT/GOG-neurotoxicity (Ntx) subscale (short), and the gastrointestinal (GI) symptoms subscale.

RESULTS

At the end of treatment, patients receiving Cis-RT + CP reported a statistically significant decreased QOL when compared to CP. The decline in QOL was reflected in physical well-being, functional well-being, and endometrial cancer specific concerns, but the minimally important differences (MID) were not considered clinically meaningful. Patients in both groups reported increased chemotherapy-induced Ntx symptoms with the CP group having worse scores and reaching peak symptoms at the time of chemotherapy completion. Patients on Cis-RT + CP reported statistically significantly worse GI symptoms after radiation therapy compared to patients on CP, this occurred across assessment intervals, though the MID was not meaningful. Psychometric evaluations indicated that the GI symptom scale is reliable, valid, and responsive to change.

CONCLUSIONS

PROs indicate that the chemoradiotherapy group experienced worse HRQoL and GI toxicity compared to patients randomized to chemotherapy alone for locally advanced endometrial cancer though based on the MID, these were not clinically meaningful differences. The GI symptom subscale was a reliable and valid scale that has value for future trials.

TRIAL REGISTRATION

NCT00942357.

Prognostic nomogram for progression-free survival in patients with BRCA mutations and platinum-sensitive recurrent ovarian cancer on maintenance olaparib therapy following response to chemotherapy

BACKGROUND

The impact of maintenance therapy with PARP inhibitors (PARPi) on progression-free survival (PFS) in patients with BRCA mutations and platinum-sensitive recurrent ovarian cancer (PSROC) varies widely. Individual prognostic factors do not reliably distinguish patients who progress early from those who have durable benefit. We developed and validated a prognostic nomogram to predict PFS in these patients.

METHODS

The nomogram was developed using data from a training patient cohort with BRCA mutations and high-grade serous PSROC on the placebo arm of two maintenance therapy trials, Study 19 and SOLO2/ENGOT-ov21. We performed multivariable Cox regression analysis based on pre-treatment characteristics to develop a nomogram that predicts PFS. We assessed the discrimination and validation of the nomogram in independent validation patient cohorts treated with maintenance olaparib.

RESULTS

The nomogram includes four PFS predictors: CA-125 at randomisation, platinum-free interval, presence of measurable disease and number of prior lines of platinum therapy. In the training (placebo) cohort (internal validation C-index 0.64), median PFS in the model-predicted good, intermediate and poor-risk groups was: 7.7 (95% CI 5.3-11.3), 5.4 (4.8-5.8) and 2.9 (2.8-4.4) months, respectively. In the validation (olaparib) cohort (C-index 0.71), median PFS in the model-predicted good, intermediate and poor-risk groups was: not reached, 16.6 (13.1-22.4) and 8.3 (7.1-10.8) months, respectively. The nomogram showed good calibration in the validation cohort (calibration plot).

CONCLUSIONS

This nomogram can be used to predict PFS and counsel patients with BRCA mutations and PSROC prior to maintenance olaparib and for stratification of patients in trials of maintenance therapies.

Sequential Phase II clinical trials evaluating CRLX101 as monotherapy and in combination with bevacizumab in recurrent ovarian cancer

BACKGROUND

Topoisomerase-1 inhibitors are an important class of cytotoxics associated with toxicity that limits their use. CRLX101 is a novel cyclodextrin-containing polymer conjugate of camptothecin (CPT) that self-assembles into nanoparticles to deliver sustained levels of active CPT into cancer cells while substantially reducing systemic exposure.

METHODS

We conducted sequential phase II, open label, single arm clinical trials to evaluate CRLX101 as a single agent (n = 29) and with bevacizumab (Bev) (n = 34). Patients (pts) had measurable recurrent epithelial ovarian, tubal or primary peritoneal cancer, that could be platinum refractory, resistant or sensitive. Cohort A (Single agent CRLX101) allowed up to 3 prior chemotherapy regimens, but no prior topo-1 inhibitors. Pts received CRLX101 15 mg/m² IV every 14 days Q28 with response evaluation every 2 cycles. Cohort B also received Bev 10 mg/kg D1,15 Q28, and included only platinum resistant disease with up to 2 prior lines, and more rigorous eligibility criteria.

RESULTS

CRLX101 was well tolerated other than nausea, fatigue and anemia. 29 pts. received a median of 3 (1-16) cycles with a clinical benefit rate (CBR) of 68% and overall response rate (ORR) of 11%. With the addition of Bev in Cohort B (n = 34), the CBR was increased to 95% and the ORR to 18%. PFS was 4.5 months (0.9 to 15.9 months) in Cohort A and 6.5 months (2.8 to 14.4 months) in Cohort B. Bev increased the incidence of hypertension and qualitatively increased bladder toxicities, but without SAEs.

CONCLUSIONS

CRLX101 meets the clinical need for an effective and tolerable topoisomerase I inhibitor and can be safely combined with bevacizumab.