First-in-class Microbial Ecosystem Therapeutic 4 (MET4) in combination with immune checkpoint inhibitors in patients with advanced solid tumors (MET4-IO trial)

BACKGROUND

The intestinal microbiome has been associated with response to immune checkpoint inhibitors (ICIs) in humans and causally implicated in ICI responsiveness in animal models. Two recent human trials demonstrated that fecal microbiota transplant (FMT) from ICI responders can rescue ICI responses in refractory melanoma, but FMT has specific limitations to scaled use.

PATIENTS AND METHODS

We conducted an early-phase clinical trial of a cultivated, orally delivered 30-species microbial consortium (Microbial Ecosystem Therapeutic 4, MET4) designed for co-administration with ICIs as an alternative to FMT and assessed safety, tolerability and ecological responses in patients with advanced solid tumors.

RESULTS

The trial achieved its primary safety and tolerability outcomes. There were no statistically significant differences in the primary ecological outcomes; however, differences in MET4 species relative abundance were evident after randomization that varied by patient and species. Increases in the relative abundance of several MET4 taxa, including Enterococcus and Bifidobacterium, taxa previously associated with ICI responsiveness, were observed and MET4 engraftment was associated with decreases in plasma and stool primary bile acids.

CONCLUSIONS

This trial is the first report of the use of a microbial consortium as an alternative to FMT in advanced cancer patients receiving ICI and the results justify the further development of microbial consortia as a therapeutic co-intervention for ICI treatment in cancer.

Efficacy and Safety of Nivolumab Plus Ipilimumab vs Nivolumab Alone for Treatment of Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck: The Phase 2 CheckMate 714 Randomized Clinical Trial

Importance

There remains an unmet need to improve clinical outcomes in patients with recurrent or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN).

Objective

To evaluate clinical benefit of first-line nivolumab plus ipilimumab vs nivolumab alone in patients with R/M SCCHN.

Design, Setting, and Participants

The CheckMate 714, double-blind, phase 2 randomized clinical trial was conducted at 83 sites in 21 countries between October 20, 2016, and January 23, 2019. Eligible participants were aged 18 years or older and had platinum-refractory or platinum-eligible R/M SCCHN and no prior systemic therapy for R/M disease. Data were analyzed from October 20, 2016 (first patient, first visit), to March 8, 2019 (primary database lock), and April 6, 2020 (overall survival database lock).

Interventions

Patients were randomized 2:1 to receive nivolumab (3 mg/kg intravenously [IV] every 2 weeks) plus ipilimumab (1 mg/kg IV every 6 weeks) or nivolumab (3 mg/kg IV every 2 weeks) plus placebo for up to 2 years or until disease progression, unacceptable toxic effects, or consent withdrawal.

Main Outcomes and Measures

The primary end points were objective response rate (ORR) and duration of response between treatment arms by blinded independent central review in the population with platinum-refractory R/M SCCHN. Exploratory end points included safety.

Results

Of 425 included patients, 241 (56.7%; median age, 59 [range, 24-82] years; 194 males [80.5%]) had platinum-refractory disease (nivolumab plus ipilimumab, n = 159; nivolumab, n = 82) and 184 (43.3%; median age, 62 [range, 33-88] years; 152 males [82.6%]) had platinum-eligible disease (nivolumab plus ipilimumab, n = 123; nivolumab, n = 61). At primary database lock, the ORR in the population with platinum-refractory disease was 13.2% (95% CI, 8.4%-19.5%) with nivolumab plus ipilimumab vs 18.3% (95% CI, 10.6%-28.4%) with nivolumab (odds ratio [OR], 0.68; 95.5% CI, 0.33-1.43; P = .29). Median duration of response for nivolumab plus ipilimumab was not reached (NR) (95% CI, 11.0 months to NR) vs 11.1 months (95% CI, 4.1 months to NR) for nivolumab. In the population with platinum-eligible disease, the ORR was 20.3% (95% CI, 13.6%-28.5%) with nivolumab plus ipilimumab vs 29.5% (95% CI, 18.5%-42.6%) with nivolumab. The rates of grade 3 or 4 treatment-related adverse events with nivolumab plus ipilimumab vs nivolumab were 15.8% (25 of 158) vs 14.6% (12 of 82) in the population with platinum-refractory disease and 24.6% (30 of 122) vs 13.1% (8 of 61) in the population with platinum-eligible disease.

Conclusions and Relevance

The CheckMate 714 randomized clinical trial did not meet its primary end point of ORR benefit with first-line nivolumab plus ipilimumab vs nivolumab alone in platinum-refractory R/M SCCHN. Nivolumab plus ipilimumab was associated with an acceptable safety profile. Research to identify patient subpopulations in R/M SCCHN that would benefit from nivolumab plus ipilimumab over nivolumab monotherapy is warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT02823574.

Tumor-Naïve Circulating Tumor DNA as an Early Response Biomarker for Patients Treated With Immunotherapy in Early Phase Clinical Trials

PURPOSE

To evaluate early circulating tumor DNA (ctDNA) kinetics using a tumor-naïve assay and correlate it with clinical outcomes in early phase immunotherapy (IO) trials.

METHODS

Plasma samples were analyzed using a 425-gene next-generation sequencing panel at baseline and before cycle 2 (3-4 weeks) in patients with advanced solid tumors treated with investigational IO agents. Variant allele frequency (VAF) for mutations in each gene, mean VAF (mVAF) from all mutations, and change in mVAF between both time points were calculated. Hyperprogression (HyperPD) was measured using Matos and Caramella criteria.

RESULTS

A total of 162 plasma samples were collected from 81 patients with 27 different tumor types. Patients were treated in 37 different IO phase I/II trials, 72% of which involved a PD-1/PD-L1 inhibitor. ctDNA was detected in 122 plasma samples (75.3%). A decrease in mVAF from baseline to precycle 2 was observed in 24 patients (37.5%) and was associated with longer progression-free survival (hazard ratio [HR], 0.43; 95% CI, 0.24 to 0.77; P < .01) and overall survival (HR, 0.54; 95% CI, 0.3 to 0.96; P = .03) compared with an increase. These differences were more marked if there was a >50% decrease in mVAF for both progression-free survival (HR, 0.29; 95% CI, 0.13 to 0.62; P < .001) and overall survival (HR, 0.23; 95% CI, 0.09 to 0.6; P = .001). No differences in mVAF changes were observed between the HyperPD and progressive disease patients.

CONCLUSION

A decrease in ctDNA within 4 weeks of treatment was associated with treatment outcomes in patients in early phase IO trials. Tumor-naïve ctDNA assays may be useful for identifying early treatment benefits in phase I/II IO trials.

Characterization of Patients With Metastatic Renal Cell Carcinoma Experiencing Complete Response to First-line Therapies: Results From the International Metastatic Renal Cell Carcinoma Database Consortium

PURPOSE

Clinical trials have demonstrated higher complete response rates in the immuno-oncology-based combination arms than in the tyrosine kinase inhibitor arms in patients with metastatic renal cell carcinoma. We aimed to characterize real-world patients who experienced complete response to the contemporary first-line therapies.

MATERIALS AND METHODS

Using the International Metastatic Renal Cell Carcinoma Database Consortium, response-evaluable patients who received frontline immuno-oncology-based combination therapy or tyrosine kinase inhibitor monotherapy were analyzed. Baseline characteristics of patients and post-landmark overall survival were compared based on best overall response, as per RECIST 1.1.

RESULTS

A total of 52 (4.6%) of 1,126 and 223 (3.0%) of 7,557 patients experienced complete response to immuno-oncology-based and tyrosine kinase inhibitor therapies, respectively (P = .005). An adjusted odds ratio for complete response achieved by immuno-oncology-based combination therapy (vs tyrosine kinase inhibitor monotherapy) was 1.56 (95% CI 1.11-2.17; P = .009). Among patients who experienced complete response, the immuno-oncology-based cohort had a higher proportion of non-clear cell histology (15.9% and 4.7%; P = .016), sarcomatoid dedifferentiation (29.8% and 13.5%; P = .014), and multiple sites of metastases (80.4% and 50.0%; P < .001) than the tyrosine kinase inhibitor cohort. Complete response was independently associated with post-landmark overall survival benefit in both the immuno-oncology-based and tyrosine kinase inhibitor cohorts, giving respective adjusted hazard ratios of 0.17 (95% CI 0.04-0.72; P = .016) and 0.28 (95% CI 0.21-0.38; P < .001).

CONCLUSIONS

The complete response rate was not as high in the real-world population as in the clinical trial population. Among those who experienced complete response, several adverse clinicopathological features were more frequently observed in the immuno-oncology-based cohort than in the tyrosine kinase inhibitor cohort. Complete response was an indicator of favorable overall survival.

Feasibility and acceptability of remote symptom monitoring (RSM) in older adults during treatment for metastatic prostate cancer

INTRODUCTION

Emerging data support multiple benefits of remote symptom monitoring (RSM) during chemotherapy to improve outcomes. However, these studies have not focused on older adults and do not include treatments beyond chemotherapy. Although chemotherapy, androgen receptor axis-targeted therapies (ARATs), and radium-223 prolong survival, toxicities are substantial and increased in older adults with metastatic prostate cancer (mPC). We aimed to assess RSM feasibility among older adults receiving life-prolonging mPC treatments.

MATERIALS AND METHODS

Older adults aged 65+ starting chemotherapy, an ARAT, or radium-223 for mPC were enrolled in a multicentre prospective cohort study. As part of the RSM package, participants completed the Edmonton Symptom Assessment Scale (ESAS) daily and detailed questionnaires assessing mood, anxiety, fatigue, insomnia, and pain weekly online or by phone throughout one treatment cycle (3-4 weeks). Alerts were sent to the clinical oncology team for severe symptoms (ESAS ≥7). Participants also completed an end of study questionnaire that assessed study burden and satisfaction. Descriptive statistics were used to determine recruitment and retention rates, participant response rates to daily and weekly questionnaires, clinician responses to alerts, and participant satisfaction rates. An inductive descriptive approach was used to categorize open-ended responses about study benefits, challenges, and recommendations into relevant themes.

RESULTS

Ninety males were included (mean age 77 years, 48% ARAT, 38% chemotherapy, and 14% radium-223). Approximately 38% of patients preferred phone-based RSM. Patients provided RSM responses in 1216 out of 1311 daily questionnaires (93%). Over 93% of participants were satisfied (36%), very satisfied (43%), or extremely satisfied (16%) with RSM, although daily reporting was reported by several (8%) as burdensome. Nearly 45% of patients reported severe symptoms during RSM. Most symptom alerts sent to the oncology care team were acknowledged (97%) and 53% led to follow-ups with a nurse or physician for additional care.

DISCUSSION

RSM is feasible and acceptable to older adults with mPC, but accommodation needs to be made for phone-based RSM. The optimal frequency and duration of RSM also needs to be established.

First-in-human phase I study of the OX40 agonist GSK3174998 with or without pembrolizumab in patients with selected advanced solid tumors (ENGAGE-1)

BACKGROUND

The phase I first-in-human study ENGAGE-1 evaluated the humanized IgG1 OX40 agonistic monoclonal antibody GSK3174998 alone (Part 1 (P1)) or in combination with pembrolizumab (Part 2 (P2)) in patients with advanced solid tumors.

METHODS

GSK3174998 (0.003-10 mg/kg) ± pembrolizumab (200 mg) was administered intravenously every 3 weeks using a continuous reassessment method for dose escalation. Primary objectives were safety and tolerability; secondary objectives included pharmacokinetics, immunogenicity, pharmacodynamics, and clinical activity.

RESULTS

138 patients were enrolled (45 (P1) and 96 (P2, including 3 crossovers)). Treatment-related adverse events occurred in 51% (P1) and 64% (P2) of patients, fatigue being the most common (11% and 24%, respectively). No dose-toxicity relationship was observed, and maximum-tolerated dose was not reached. Dose-limiting toxicities (P2) included Grade 3 (G3) pleural effusion and G1 myocarditis with G3 increased troponin. GSK3174998 ≥0.3 mg/kg demonstrated pharmacokinetic linearity and >80% receptor occupancy on circulating T cells; 0.3 mg/kg was selected for further evaluation. Limited clinical activity was observed for GSK3174998 (P1: disease control rate (DCR) ≥24 weeks 9%) and was not greater than that expected for pembrolizumab alone (P2: overall response rate 8%, DCR ≥24 weeks 28%). Multiplexed immunofluorescence data from paired biopsies suggested that increased infiltration of natural killer (NK)/natural killer T (NKT) cells and decreased regulatory T cells (Tregs) in the tumor microenvironment may contribute to clinical responses: CD16+CD56-CD134+ NK /NKT cells and CD3+CD4+FOXP3+CD134+ Tregs exhibited the largest magnitude of change on treatment, whereas CD3+CD8+granzyme B+PD-1+CD134+ cytotoxic T cells were the least variable. Tumor gene expression profiling revealed an upregulation of inflammatory responses, T-cell proliferation, and NK cell function on treatment with some inflammatory cytokines upregulated in peripheral blood. However, target engagement, evidenced by pharmacologic activity in peripheral blood and tumor tissue, did not correlate with clinical efficacy. The low number of responses precluded identifying a robust biomarker signature predictive of response.

CONCLUSIONS

GSK3174998±pembrolizumab was well tolerated over the dose range tested and demonstrated target engagement. Limited clinical activity does not support further development of GSK3174998±pembrolizumab in advanced cancers.

TRIAL REGISTRATION NUMBER

NCT02528357.

Evaluating the impact of early identification of asymptomatic brain metastases in metastatic renal cell carcinoma

BACKGROUND

Brain metastases (BM) in metastatic renal cell carcinoma (mRCC) have been reported to be present in up to 25% of patients diagnosed with mRCC. There is limited published literature evaluating the role of routine intra-cranial imaging for the screening of asymptomatic BM in mRCC.

AIMS

To evaluate the potential utility of routine intra-cranial imaging, a retrospective cohort study was conducted to characterize the outcomes of mRCC patients who presented with asymptomatic BM, as compared to symptomatic BM.

METHODS AND RESULTS

The Canadian Kidney Cancer Information System (CKCis) database was used to identify mRCC patients diagnosed with BM. This cohort was divided into two groups based on the presence or absence of BM symptoms. Details regarding patient demographics, disease characteristics, systemic treatments, BM characteristics and survival outcomes were extracted. Statistical analysis was through chi-square tests, analysis of variance, and Kaplan-Meier method to characterize survival outcomes. A p-value of <0.05 was considered statistically significant for all analyses. A total of 267 mRCC patients with BM were identified of which 106 (40%) presented with asymptomatic disease. The majority of patients presented with multiple (i.e., >1) BM (75%) with no significant differences noted in number of BM or BM-directed therapy received in symptomatic, as compared to asymptomatic BM patients. Median [95% confidence interval (CI)] overall survival (OS) from mRCC diagnosis was 42 months (95% CI: 32-62) for patients with asymptomatic BM, and 39 months (95% CI: 29-48) with symptomatic BM (p = 0.10). OS from time of BM diagnosis was 28 months (95% CI: 18-42) for the asymptomatic BM group, as compared to 13 months (95% CI: 10-21) in the symptomatic BM group (p = 0.04).

CONCLUSIONS

Given a substantial proportion of patients may present with asymptomatic BM, limiting intra-cranial imaging to patients with symptomatic BM, may be associated with a missed opportunity for timely diagnosis and treatment. The utility of routine intra-cranial imaging in patients with renal cell carcinoma, warrants further prospective evaluation.

The role of frailty in modifying physical function and quality of life over time in older men with metastatic castration-resistant prostate cancer

INTRODUCTION

As treatment options for metastatic castration-resistant prostate cancer (mCRPC) expand and its patient population ages, consideration of frailty is increasingly relevant. Using a novel frailty index (FI) and two common frailty screening tools, we examined quality of life (QoL) and physical function (PF) in frail versus non-frail men receiving treatment for mCRPC.

MATERIALS AND METHODS

Men aged 65+ starting docetaxel chemotherapy, abiraterone, or enzalutamide for mCRPC were enrolled in a multicenter prospective cohort study. QoL, fatigue, pain, and mood were measured with the Functional Assessment of Cancer Therapy-General scale, the Edmonton Symptom Assessment System tiredness and pain subscales, and the Patient Health Questionnaire-9. PF was evaluated with grip strength, four-meter gait speed, five times Sit-to-Stand Test, and instrumental activities of daily living. Frailty was determined using the Vulnerable Elders Survey (VES-13), the Geriatric 8 (G8), and an FI constructed from 36 variables spanning laboratory abnormalities, geriatric syndromes, functional status, social support, as well as emotional, cognitive, and physical deficits. We categorized patients as non-frail (FI ≤ 0.2, VES < 3, G8 > 14), pre-frail (FI > 0.20, ≤0.35), or frail (FI > 0.35, VES ≥ 3, G8 ≤ 14); assessed correlation between the three tools; and performed linear mixed-effects regression analyses to examine longitudinal differences in outcomes (0, 3, 6 months) by frailty status. A sensitivity analysis with worst-case imputation was conducted to explore attrition.

RESULTS

We enrolled 175 men (mean age 74.9 years) starting docetaxel (n = 71), abiraterone (n = 37), or enzalutamide (n = 67). Our FI demonstrated moderate correlation with the VES-13 (r = 0.607, p < 0.001) and the G8 (r = -0.520, p < 0.001). Baseline FI score was associated with worse QoL (p < 0.001), fatigue (p < 0.001), pain (p < 0.001), mood (p < 0.001), PF (p < 0.001), and higher attrition (p < 0.01). Over time, most outcomes remained stable, although pain improved, on average, regardless of frailty status (p = 0.007), while fatigue (p = 0.045) and mood (p = 0.015) improved in frail patients alone.

DISCUSSION

Among older men receiving care for mCRPC, frailty may be associated with worse baseline QoL and PF, but over time, frail patients may experience largely similar trends in QoL and PF as their non-frail counterparts. Further study with larger sample size and longer follow-up may help elucidate how best to incorporate frailty into treatment decision-making for mCRPC.

UnCHAARTED territory: The role of docetaxel rechallenge following chemohormonal therapy for metastatic castration-sensitive prostate cancer

OBJECTIVE

To assess the effectiveness of docetaxel rechallenge (DR) for metastatic castration-resistant prostate cancer (mCRPC) following chemohormonal therapy for metastatic castrate-sensitive prostate cancer (mCSPC). Additionally, we sought to define clinical factors predicting treatment response.

PATIENTS AND METHODS

Retrospective analysis of men treated with docetaxel for mCSPC and then rechallenged in the mCRPC setting from four cancer centers in Ontario, Canada. Prostate specific antigen (PSA) response, progression-free survival (PFS), and overall survival (OS) following DR were evaluated.

RESULTS

Fifty five patients were identified between 2015 and 2020. Prior to DR, 94.5% of patients received androgen-receptor axis targeted therapy, 20% received radium-223, and 1.8% received cabazitaxel. Among 54 evaluable patients, 27.8% had a PSA decline ≥50%. Median PFS was 4.1 months (95% CI, 2.1-4.8) and median OS from androgen deprivation therapy initiation was 38.3 months (95% CI, 32.9-41.0). A Gleason Score of ≥8 was an independent predictor of prolonged PFS (HR 0.32, 95% CI, 0.12-0.81; P=0.02).

CONCLUSIONS

DR following chemohormonal therapy for mCSPC produced a meaningful PSA response in approximately one-quarter of patients, with relatively short PFS. The impact of Gleason Score on docetaxel response warrants further investigation.

Evaluation of the patient experience of symptomatic adverse events on Phase I clinical trials using PRO-CTCAE

BACKGROUND

Adverse event (AE) reporting in early-phase clinical trials is essential in determining the tolerability of experimental anticancer therapies. The patient-reported outcome version of the CTCAE (PRO-CTCAE) evaluates AE components such as severity and interference in daily life. The aim of this study was to correlate the grade of clinician-reported AEs with patients' reported experience of these toxicities using PRO-CTCAE.

METHODS

Patients with advanced solid tumours enrolled on Phase I clinical trials were surveyed using the PRO-CTCAE. Symptomatic AEs were recorded by physicians using the CTCAE. A logistic regression model was used to assess associations between CTCAE grade and PRO responses.

RESULTS

Of 219 evaluable patients, 81 experienced a high-grade (3/4) clinician-reported symptom, and of these, only 32 (40%) and 26 (32%) patients concordantly reported these as either severe or very severe, and interfering with daily life either 'quite a bit' or 'very much', respectively. Of the 137 patients who experienced a low-grade (1/2) clinician-reported AE as their worst symptom, 98 (72%) and 118 (86%) patients concordantly reported these as either mild-moderate severity and minimally interfering with daily life, respectively. There was a statistically significant association between clinician-reported AE grade and interference. Interference scores were also associated with dose reductions.

CONCLUSION

This is the first study to explore patient-reported severity and interference from symptomatic toxicities and compare clinician grading of the same toxicities. The study provided further evidence to support the added value of the PRO-CTCAE in Phase I oncology trials, which would make AE reporting patient-centred. Further work is needed to determine how this would affect the assessment of tolerability.

Manufacturing-dependent change in biological activity of the TLR4 agonist GSK1795091 and implications for lipid A analog development

A phase I trial (NCT03447314; 204686) evaluated the safety and efficacy of GSK1795091, a Toll-like receptor 4 (TLR4) agonist, in combination with immunotherapy (GSK3174998 [anti-OX40 monoclonal antibody], GSK3359609 [anti-ICOS monoclonal antibody], or pembrolizumab) in patients with solid tumors. The primary endpoint was safety; other endpoints included efficacy, pharmacokinetics, and pharmacodynamics (PD). Manufacturing of GSK1795091 formulation was modified during the trial to streamline production and administration, resulting in reduced PD (cytokine) activity. Fifty-four patients received GSK1795091 with a combination partner; 32 received only the modified GSK1795091 formulation, 15 received only the original formulation, and seven switched mid-study from the original to the modified formulation. Despite the modified formulation demonstrating higher systemic GSK1795091 exposure compared with the original formulation, the transient, dose-dependent elevations in cytokine and chemokine concentrations were no longer observed (e.g., IP-10, IL10, IL1-RA). Most patients (51/54; 94%) experienced ≥1 treatment-emergent adverse event (TEAE) during the study. Safety profiles were similar between formulations, but a higher incidence of TEAEs associated with immune responses (chills, fatigue, pyrexia, nausea, and vomiting) were observed with the original formulation. No conclusions can be made regarding GSK1795091 anti-tumor activity due to the limited data collected. Manufacturing changes were hypothesized to have caused the change in biological activity in this study. Structural characterization revealed GSK1795091 aggregate size in the modified formulation to be twice that in the original formulation, suggesting a negative correlation between GSK1795091 aggregate size and PD activity. This may have important clinical implications for future development of structurally similar compounds.

Health-related quality of life with pembrolizumab monotherapy in patients with previously treated advanced microsatellite instability high/mismatch repair deficient endometrial cancer in the KEYNOTE-158 study

OBJECTIVE

Pembrolizumab demonstrated a clinically meaningful objective response rate in patients with previously treated, advanced MSI-H/dMMR endometrial cancer in the multicohort phase 2 KEYNOTE-158 study (ClinicalTrials.gov, NCT02628067). We present health-related quality of life (HRQoL) results for these patients.

METHODS

This analysis included patients from cohorts D (endometrial cancer with any MSI status) and K (any MSI-H/dMMR solid tumor except colorectal) who had previously treated, advanced MSI-H/dMMR endometrial cancer. Patients received pembrolizumab 200 mg Q3W for 35 cycles. EORTC QLQ-C30 and EQ-5D-3L questionnaires were administered at baseline, at regular intervals during treatment, and 30 days after treatment discontinuation. Pre-specified exploratory analyses included changes from baseline to week 9 in QLQ-C30 global health status (GHS)/QoL and EQ-5D-3L visual analog scale (VAS) score for all patients and by best overall response.

RESULTS

84 of 90 enrolled patients completed ≥1 HRQoL questionnaire and were included in the analysis. QLQ-C30 and EQ-5D-3L compliance rates were 90% and 94%, respectively, at baseline, and 92% and 93% at week 9. Mean (95% CI) QLQ-C30 GHS/QoL scores improved from baseline to week 9 by 6.08 (0.71-11.46) points in the overall population, with greater improvement in patients who achieved complete or partial response (11.67 [5.33-18.00]-point increase). Mean (95% CI) EQ-5D-3L VAS scores improved by 6.00 (2.25-9.75) points in the overall population and 9.11 (5.24-12.98) points in patients with CR/PR.

CONCLUSIONS

Pembrolizumab maintained or improved HRQoL in patients with previously treated, advanced MSI-H/dMMR endometrial cancer, further supporting efficacy and safety results from KEYNOTE-158 and pembrolizumab use in this setting.

A Randomized Phase II Study of MEDI0680 in Combination with Durvalumab versus Nivolumab Monotherapy in Patients with Advanced or Metastatic Clear-cell Renal Cell Carcinoma

PURPOSE

MEDI0680 is a humanized anti-programmed cell death-1 (PD-1) antibody, and durvalumab is an anti-PD-L1 antibody. Combining treatment using these antibodies may improve efficacy versus blockade of PD-1 alone. This phase II study evaluated antitumor activity and safety of MEDI0680 plus durvalumab versus nivolumab monotherapy in immunotherapy-naïve patients with advanced clear-cell renal cell carcinoma who received at least one prior line of antiangiogenic therapy.

PATIENTS AND METHODS

Patients received either MEDI0680 (20 mg/kg) with durvalumab (750 mg) or nivolumab (240 mg), all intravenous, every 2 weeks. The primary endpoint was investigator-assessed objective response rate (ORR). Secondary endpoints included best overall response, progression-free survival (PFS), safety, overall survival (OS), and immunogenicity. Exploratory endpoints included changes in circulating tumor DNA (ctDNA), baseline tumor mutational burden, and tumor-infiltrated immune cell profiles.

RESULTS

Sixty-three patients were randomized (combination, n = 42; nivolumab, n = 21). ORR was 16.7% [7/42; 95% confidence interval (CI), 7.0-31.4] with combination treatment and 23.8% (5/21; 95% CI, 8.2-47.2) with nivolumab. Median PFS was 3.6 months in both arms; median OS was not reached in either arm. Because of adverse events, 23.8% of patients discontinued MEDI0680 and durvalumab and 14.3% of patients discontinued nivolumab. In the combination arm, reduction in ctDNA fraction was associated with longer PFS. ctDNA mutational analysis did not demonstrate an association with response in either arm. Tumor-infiltrated immune profiles showed an association between immune cell activation and response in the combination arm.

CONCLUSIONS

MEDI0680 combined with durvalumab was safe and tolerable; however, it did not improve efficacy versus nivolumab monotherapy.

Pre-encoded responsiveness to type I interferon in the peripheral immune system defines outcome of PD1 blockade therapy

Type I interferons (IFN-Is) are central regulators of anti-tumor immunity and responses to immunotherapy, but they also drive the feedback inhibition underlying therapeutic resistance. In the present study, we developed a mass cytometry approach to quantify IFN-I-stimulated protein expression across immune cells and used multi-omics to uncover pre-therapy cellular states encoding responsiveness to inflammation. Analyzing peripheral blood cells from multiple cancer types revealed that differential responsiveness to IFN-Is before anti-programmed cell death protein 1 (PD1) treatment was highly predictive of long-term survival after therapy. Unexpectedly, IFN-I hyporesponsiveness efficiently predicted long-term survival, whereas high responsiveness to IFN-I was strongly associated with treatment failure and diminished survival time. Peripheral IFN-I responsive states were not associated with tumor inflammation, identifying a disconnect between systemic immune potential and 'cold' or 'hot' tumor states. Mechanistically, IFN-I responsiveness was epigenetically imprinted before therapy, poising cells for differential inflammatory responses and dysfunctional T cell effector programs. Thus, we identify physiological cell states with clinical importance that can predict success and long-term survival of PD1-blocking immunotherapy.

A novel methylated cell-free DNA marker panel to monitor treatment response in metastatic prostate cancer

Aim: This study examined circulating cell-free DNA (cfDNA) biomarkers associated with androgen treatment resistance in metastatic castration resistance prostate cancer (mCRPC). Materials & methods: We designed a panel of nine candidate cfDNA methylation markers using droplet digital PCR (Methyl-ddPCR) and assessed methylation levels in sequentially collected cfDNA samples from patients with mCRPC. Results: Increased cfDNA methylation in eight out of nine markers during androgen-targeted treatment correlated with a faster time to clinical progression. Cox proportional hazards modeling and logistic regression analysis further confirmed that higher cfDNA methylation during treatment was significantly associated with clinical progression. Conclusion: Overall, our findings have revealed a novel methylated cfDNA marker panel that could aid in the clinical management of metastatic prostate cancer.

Outcomes of Radiation Therapy Plus Immunotherapy in Metastatic Renal Cell Carcinoma: Results From the Canadian Kidney Cancer Information System

Purpose

With the integration of immunotherapy (IO) agents in the management of metastatic renal cell carcinoma (mRCC), there has been interest in the combined use with radiation therapy (RT). However, real world data are limited. The purpose of this study was to evaluate outcomes in patients with mRCC receiving both RT and IO compared with IO alone.

Methods and Materials

Data were collected from Canadian Kidney Cancer Information System from January 2011 to September 2019 across 14 academic centers. Patients with mRCC who received IO as first- or second-line therapy were included. RT was categorized as radical dose or palliative dose. Kaplan-Meier estimates were reported for overall survival (OS) and time to treatment failure. Cox proportional hazard models were used adjusted for age and International Metastatic RCC Database Consortium risk categories.

Results

In total, 505 patients were included in the study: 179 received RT + IO and 326 received IO alone. Two-year OS for the RT + IO group was 55.0% compared with 66.4% in the IO alone cohort (adjusted hazard ratio [aHR], 1.38; P = .07). At 2 years, 12.2% of the RT + IO patients remained on therapy versus 30.9% in the IO alone group (aHR, 1.30; P = .02). For patients receiving first-line therapy, 2-year OS in the RT + IO group was 56.4% versus 78.4% in the IO alone arm, though this difference was not statistically significant (aHR, 1.23; P = .56). For patients receiving radical dose and palliative dose, 2-year OS was 57.0% and 53.9%, respectively (aHR, 0.86; P = .63).

Conclusions

In this descriptive analysis, more than one-third of patients with mRCC received RT and demonstrated inferior outcomes compared with IO alone. Potential explanations include greater presence of adverse metastatic sites in those receiving RT. Prospective clinical trials evaluating potential benefits of RT in an IO era remain an important need.

Evaluation of pembrolizumab monotherapy in patients with previously treated advanced salivary gland carcinoma in the phase 2 KEYNOTE-158 study

AIM

We evaluated pembrolizumab monotherapy in patients with advanced salivary gland carcinoma on the phase 2 KEYNOTE-158 study (NCT02628067).

METHODS

Eligible patients had histologically/cytologically confirmed advanced salivary gland carcinoma with prior failure or intolerance to standard therapy, measurable disease per Response Evaluation Criteria in Solid Tumours (RECIST) v1.1., and ECOG performance status 0-1. Patients were enrolled irrespective of tumour PD-L1 expression. Patients received pembrolizumab 200 mg Q3W for up to 35 cycles (∼2 years). Radiographic imaging occurred every 9 weeks through month 12, then every 12 weeks. PD-L1 positivity was defined as combined positive score ≥1 (evaluated using PD-L1 IHC 22C3 pharmDx). The primary endpoint was objective response rate per RECIST v1.1.

RESULTS

In total, 109 patients were enrolled (PD-L1-positive, 25.7%). At the data cutoff (October 5, 2020), median follow-up was 53.3 (range, 50.8-56.3) months. Objective response rate was 4.6% (95% CI, 1.5-10.4%) among all patients (complete response, n = 1; partial response, n = 4) and was 10.7% (95% CI, 2.3-28.2%) in patients with PD-L1-positive disease and 2.6% (95% CI, 0.3-9.1%) in patients with PD-L1-negative disease. Duration of response was ≥24 months for all 5 responders; median duration of response was not reached (range, 25.1-49.8+ months). Median progression-free survival and overall survival were 4.0 (95% CI, 2.6-4.2) and 21.1 (95% CI, 15.9-25.5) months, respectively. Treatment-related adverse events occurred in 75.2% (grade 3-4, 15.6%; grade 5, 0%) of patients. Immune-mediated adverse events occurred in 22.0% of patients (grade 3, 5.5%; grade 4-5, 0).

CONCLUSIONS

A small subset of patients with advanced salivary gland carcinoma treated with pembrolizumab had a response; all had response duration ≥2 years. The safety profile of pembrolizumab was manageable.

Results of the phase I CCTG IND.231 trial of CX-5461 in patients with advanced solid tumors enriched for DNA-repair deficiencies

CX-5461 is a G-quadruplex stabilizer that exhibits synthetic lethality in homologous recombination-deficient models. In this multicentre phase I trial in patients with solid tumors, 40 patients are treated across 10 dose levels (50–650 mg/m²) to determine the recommended phase II dose (primary outcome), and evaluate safety, tolerability, pharmacokinetics (secondary outcomes). Defective homologous recombination is explored as a predictive biomarker of response. CX-5461 is generally well tolerated, with a recommended phase II dose of 475 mg/m² days 1, 8 and 15 every 4 weeks, and dose limiting phototoxicity. Responses are observed in 14% of patients, primarily in patients with defective homologous recombination. Reversion mutations in PALB2 and BRCA2 are detected on progression following initial response in germline carriers, confirming the underlying synthetic lethal mechanism. In vitro characterization of UV sensitization shows this toxicity is related to the CX-5461 chemotype, independent of G-quadruplex synthetic lethality. These results establish clinical proof-of-concept for this G-quadruplex stabilizer. Clinicaltrials.gov NCT02719977.

G-quadruplex stabilizers, including CX-5461, exhibit synthetic lethality with loss of BRCA1/2 in preclinical models. Here the authors report the results of a phase I study of CX-5461 in patients with solid tumors enriched for DNA-repair deficiencies.

A Phase I Study Investigating AZD8186, a Potent and Selective Inhibitor of PI3Kβ/δ, in Patients with Advanced Solid Tumors

PURPOSE

To characterize safety and tolerability of the selective PI3Kβ inhibitor AZD8186, identify a recommended phase II dose (RP2D), and assess preliminary efficacy in combination with abiraterone acetate or vistusertib.

PATIENTS AND METHODS

This phase I open-label study included patients with advanced solid tumors, particularly prostate cancer, triple-negative breast cancer, and squamous non-small cell lung cancer. The study comprised four arms: (i) AZD8186 monotherapy dose finding; (ii) monotherapy dose expansion; (iii) AZD8186/abiraterone acetate (with prednisone); and (iv) AZD8186/vistusertib. The primary endpoints were safety, tolerability, and identification of the RP2D of AZD8186 monotherapy and in combination. Secondary endpoints included pharmacokinetics (PK), pharmacodynamics, and tumor and prostate-specific antigen (PSA) responses.

RESULTS

In total, 161 patients were enrolled. AZD8186 was well tolerated across all study arms, the most common adverse events being gastrointestinal symptoms. In the monotherapy dose-finding arm, four patients experienced dose-limiting toxicities (mainly rash). AZD8186 doses of 60-mg twice daily [BID; 5 days on, 2 days off (5:2)] and 120-mg BID (continuous and 5:2 dosing) were taken into subsequent arms. The PKs of AZD8186 were dose proportional, without interactions with abiraterone acetate or vistusertib, and target inhibition was observed in plasma and tumor tissue. Monotherapy and combination therapy showed preliminary evidence of limited antitumor activity by imaging and, in prostate cancer, PSA reduction.

CONCLUSIONS

AZD8186 monotherapy had an acceptable safety and tolerability profile, and combination with abiraterone acetate/prednisone or vistusertib was also tolerated. There was preliminary evidence of antitumor activity, meriting further exploration of AZD8186 in subsequent studies in PI3Kβ pathway-dependent cancers.

Increase in serum choline levels predicts for improved progression-free survival (PFS) in patients with advanced cancers receiving pembrolizumab

Background

Recent studies have demonstrated that T cells can induce vasodilation in a choline-acetyltransferase dependent manner, leading to an increase in T cell migration to infected tissues in response to viral infection, but its role in cancer is unclear. Choline acetyltransferase catalyzes the production of acetylcholine from choline and acetyl-CoA, however, acetylcholine is challenging to quantify due to its extremely short half-life while choline is stable. This study aims to correlate serum choline levels in patients with advanced solid tumors receiving pembrolizumab with treatment outcomes.

Methods

Blood samples were collected at baseline and at week 7 (pre-cycle 3) in patients treated with pembrolizumab in the INvestigator-initiated Phase 2 Study of Pembrolizumab Immunological Response Evaluation phase II trial (NCT02644369). Samples were analyzed for choline and circulating tumor DNA (ctDNA). Multivariable Cox models were used to assess the association between choline and overall survival (OS) and progression-free survival (PFS) when including ΔctDNA_C3 (the change in ctDNA from baseline to cycle 3), cohort, PD-L1 expression and tumor mutation burden (TMB). An independent validation cohort from the LIBERATE study (NCT03702309) included patients on early phase trials treated with a PD-1 inhibitor.

Results

A total of 106 pts were included in the analysis. With a median follow-up of 12.6 months, median PFS and OS were 1.9 and 13.7 months, respectively. An increase in serum choline level at week 7 compared with baseline (Δcholine_C3) in 81 pts was significantly associated with a better PFS (aHR 0.48, 95% CI 0.28 to 0.83, p=0.009), and a trend toward a better OS (aHR 0.64, 95% CI 0.37 to 1.12, p=0.119). A combination of ΔctDNA_C3 and Δcholine_C3 was prognostic for both OS and PFS. Multivariable analyses show Δcholine_C3 was a prognostic factor for PFS independent of ΔctDNA_C3, cohort, PD-L1 and TMB. In the independent validation cohort (n=51), an increase in serum choline at cycle 2 was associated with a trend to improved PFS.

Conclusions

This is the first exploratory report of serum choline levels in pan-cancer patients receiving pembrolizumab. The association between improved PFS and Δcholine_C3 suggests a possible role for the cholinergic system in the regulation of antitumor immunity. Further pre-clinical and clinical studies are required to validate this finding.

Trial registration number

NCT03702309.

Pembrolizumab in Patients With Microsatellite Instability-High Advanced Endometrial Cancer: Results From the KEYNOTE-158 Study

PURPOSE

Pembrolizumab demonstrated durable antitumor activity in patients with previously treated, advanced microsatellite instability-high or mismatch repair-deficient (MSI-H/dMMR) tumors, including endometrial cancer, in the nonrandomized, open-label, multicohort, phase II KEYNOTE-158 study (NCT02628067). We report efficacy and safety outcomes for patients with MSI-H/dMMR endometrial cancer enrolled in KEYNOTE-158.

METHODS

Eligible patients from cohorts D (endometrial cancer, regardless of MSI-H/dMMR status) and K (any MSI-H/dMMR solid tumor, except colorectal) with previously treated, advanced MSI-H/dMMR endometrial cancer received pembrolizumab 200 mg once every 3 weeks for 35 cycles. The primary end point was objective response rate per RECIST version 1.1 by independent central radiologic review. Secondary end points included duration of response, progression-free survival, overall survival, and safety.

RESULTS

As of October 5, 2020, 18 of 90 treated patients (20%) had completed 35 cycles of pembrolizumab and 52 (58%) had discontinued treatment. In the efficacy population (patients who received ≥ 1 dose of pembrolizumab and had ≥ 26 weeks of follow-up; N = 79), the median time from first dose to data cutoff was 42.6 (range, 6.4-56.1) months. The objective response rate was 48% (95% CI, 37 to 60), and median duration of response was not reached (2.9-49.7+ months). Median progression-free survival was 13.1 (95% CI, 4.3 to 34.4) months, and median overall survival was not reached (95% CI, 27.2 months to not reached). Among all treated patients, 76% had ≥ 1 treatment-related adverse event (grades 3-4, 12%). There were no fatal treatment-related events. Immune-mediated adverse events or infusion reactions occurred in 28% of patients (grades 3-4, 7%; no fatal events).

CONCLUSION

Pembrolizumab demonstrated robust and durable antitumor activity and encouraging survival outcomes with manageable toxicity in patients with previously treated, advanced MSI-H/dMMR endometrial cancer.

Abstract P1-18-17: Phase I study of cfi-402257, an oral ttk inhibitor, in patients with advanced solid tumors with breast cancer expansion cohorts

Background: TTK (also known as Mps1), a dual-specificity serine-threonine kinase, is critical for the spindle assembly checkpoint (SAC), chromosome alignment and error correction in mitosis. Inhibition of TTK causes premature mitotic exit with unattached chromosomes, resulting in chromosomal missegregation, aneuploidy and cell death. CFI-402257 is a potent (Ki = 0.09 nM, IC50 = 1.2 nM), highly selective and orally active inhibitor of TTK. Robust suppression of tumor growth was achieved upon oral dosing of single agent CFI-402257 in ER+/HER2- and triple negative breast cancer (TNBC) cell line and patient derived xenograft models. CFI-402257 demonstrated enhanced cytotoxicity in CDK4/6 inhibitor resistant ER+ breast cancer cell line models compared to parental cell lines, including those with RB1 loss. Methods: This multi-center Phase I dose escalation study (3+3 design) was designed to determine the safety, tolerability and maximum tolerated dose (MTD) of CFI-402257 and evaluate anti-tumor activity at the RP2D. CFI-402257 was dosed once daily on a continuous schedule in 28-day cycles at a starting dose of 5mg based on preclinical toxicology. Dose escalation included patients with advanced solid tumors and dose expansion at the RP2D into three expansion cohorts - Cohort A advanced solid tumors, Cohort B advanced ER+ or TNBC with 1-4 prior lines of chemotherapy for metastatic disease and Cohort C ER+/HER2- breast cancer in combination with Fulvestrant (500mg IM Day 1, 15 and 29 and then every 28 days) who have had prior treatment with an aromatase inhibitor in combination with a CDK4/6 inhibitor (&gt;= 3 months) and =&lt;1 prior chemotherapy for metastatic disease. Results: As of May 25, 2021, 66 patients had been enrolled, majority (76%) of patients received &gt;3 prior therapies before study entry and 37% of patients’ (23/66) primary malignancy was breast cancer. The maximum administered dose was 294 mg and the study has continued enrolling at the recommended phase 2 dose of 168 mg with grade 3 Neutropenia, grade 3 Febrile Neutropenia and grade 3 Colitis as the dose limiting toxicities. Only 1/6 patients experienced a DLT at 168 mg (grade 3 Neutropenia, &gt;7 days) The most common treatment emergent AEs (Gd3, &gt;5%) were Neutropenia (15.6%), Anaemia (7.8%), Hypophosphataemia and Febrile Neutropenia (6.3%). PR’s confirmed by the Investigator have been seen to date in 33% of the cohort C subjects (2/6 patients), with an additional two cPR’s seen in the breast cancer population (ER+/HER2-) from the expansion cohorts. Conclusion: CFI-402257 is generally well tolerated and continues to enroll at 168mg daily with a manageable AE profile and early signs of anti-tumor activity. Enrollment in the expansion cohorts is ongoing and updated safety and efficacy data for the previously treated ER+/HER2- population will be presented at the time of the meeting. A multi-center phase II clinical trial is planned.

Citation Format: John Hilton, Daniel J Renouf, David W Cescon, Aaron R Hansen, Albiruni RA Razak, Lee-Anne Stayner, Trisha Denny, Graham Fletcher, Tak W Mak, Mark Bray, Philippe L Bedard. Phase I study of cfi-402257, an oral ttk inhibitor, in patients with advanced solid tumors with breast cancer expansion cohorts [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 P1-18-17.

Phase I pharmacokinetic study of single agent trametinib in patients with advanced cancer and hepatic dysfunction

BACKGROUND

Trametinib is an oral MEK 1/2 inhibitor, with a single agent recommended phase 2 dose (RP2D) of 2 mg daily (QD). This study was designed to evaluate RP2D, maximum tolerated dose (MTD), and pharmacokinetic (PK) profile of trametinib in patients with advanced solid tumors who had various degrees of hepatic dysfunction (HD).

METHODS

Advanced cancer patients were stratified into 4 HD groups based on Organ Dysfunction Working Group hepatic function stratification criteria: normal (Norm), mild (Mild), moderate (Mod), severe (Sev). Dose escalation was based on "3 + 3" design within each HD group. PK samples were collected at cycle 1 days 15-16.

RESULTS

Forty-six patients were enrolled with 44 evaluable for safety [Norm=17, Mild=7, Mod (1.5 mg)=4, Mod (2 mg)=5, Sev (1 mg)=9, Sev (1.5 mg)=2] and 22 for PK analysis. Treatment related adverse events were consistent with prior trametinib studies. No treatment related deaths occurred. Dose limiting toxicities (DLTs) were evaluable in 15 patients (Mild=6, Mod (1.5 mg)=3, Mod (2 mg)=2, Sev (1 mg)=3 and Sev (1.5 mg)=1). One DLT (grade 3 acneiform rash) was observed in a Sev patient (1.5 mg). Dose interruptions or reductions due to treatment related adverse events occurred in 15 patients (34%) [Norm=9, 53%; Mild=2, 29%; Mod (1.5 mg)=1, 33%; Mod (2 mg)=2, 33%; Sev (1 mg)=1, 11%; Sev (1.5 mg)=1; 50%]. There were no significant differences across HD groups for all PK parameters when trametinib was normalized to 2 mg. However, only limited PK data were available for the Mod (n = 3) and Sev (n = 3) groups compared to Norm (n = 10) and Mild (n = 6) groups. Trametinib is heavily protein bound, with no correlation between serum albumin level and unbound trametinib fraction (p = 0.26).

CONCLUSIONS

RP2D for trametinib in Mild HD patients is 2 mg QD. There are insufficient number of evaluable patients due to difficulty of patient accrual to declare RP2D and MTD for Mod and Sev HD groups. DLTs were not observed in the highest dose cohorts that reached three evaluable patients - 1.5 mg QD in Mod group, and 1 mg QD in Sev group.

TRIAL REGISTRATION

This study was registered in the ClinicalTrials.gov website ( NCT02070549 ) on February 25, 2014. .

Inter-rater concordance and operating definitions of radiologic nodal feature assessment in human papillomavirus-positive oropharyngeal carcinoma

BACKGROUND AND PURPOSE

This study aims to evaluate the reliability of radiologic nodal feature assessment in clinical node-positive human papillomavirus-positive oropharyngeal carcinoma.

MATERIALS AND METHODS

Baseline CTs or MRIs of clinical node-positive human papillomavirus-positive oropharyngeal carcinoma diagnosed between 2012 and 2015 were reviewed independently by two neuroradiologists for seven nodal features: radiologic nodal involvement, cystic change, presence of necrosis, clustering, conglomeration, coalescence, and extranodal extension. Consensus operating definitions were derived after discussion. The features were re-reviewed in a randomly selected cohort. Levels of certainty (probability of presence: <25%, ∼50%, ∼75%, and >90%) were recorded. Interrater concordance was calculated using Cohen's kappa coefficient.

RESULTS

A total of 413 patients (826 necks) were eligible. At initial review, the inter-rater kappa values for: radiologic nodal involvement, cystic change, necrosis, clustering, conglomeration, coalescence, and extranodal extension were 0.92, 0.64, 0.48, 0.32, 0.32, 0.62, and 0.56, respectively. A re-review of 94 randomly selected cases (188 necks) after consolidation of operating definitions for nodal features showed that the inter-rater kappa values of these features were 0.83, 0.62, 0.58, 0.32, 0.18, 0.68, and 0.74 when considering ≥50% certainty as positive, and improved to 0.94, 0.66, 0.59, 0.33, 0.19, 0.76, and 0.86 when considering ≥75% certainty as positive.

CONCLUSION

Clearly defined nomenclature results in improved interrater reliability when assessing radiologic nodal features, especially for coalescent adenopathy and extranodal extension. Higher levels of certainty are associated with higher inter-rater agreement. Radiology reporting should include clear definitions of clinically relevant nodal features as well as levels of certainty to serve various needs in clinical care and research.