Tumor mutational burden is predictive of response to immune checkpoint inhibitors in MSI-high metastatic colorectal cancer.

BACKGROUND: Microsatellite instability (MSI) is a biomarker for response to immune checkpoint inhibitors (ICPIs). PD-1 inhibitors in metastatic colorectal carcinoma (mCRC) with MSI-high (MSI-H) have demonstrated a high disease control rate and favorable progression-free survival (PFS); however, reported response rates to pembrolizumab and nivolumab are variable and often <50%, suggesting that additional predictive biomarkers are needed. METHODS: Clinicopathologic data were collected from patients with MSI-H mCRC confirmed by hybrid capture-based next-generation sequencing (NGS) treated with PD-1/L1 inhibitors at five institutes. Tumor mutational burden (TMB) was determined on 0.8-1.1 Mb of sequenced DNA and reported as mutations/Mb. Potential biomarkers of response and time to progression were analyzed by univariate and multivariate analyses. Once TMB was confirmed as a predictive biomarker, a larger dataset of 18 140 unique CRC patients was analyzed to define the relevance of the identified TMB cut-point. RESULTS: A total of 22 patients were treated with PD-1/L1 inhibitors including 19 with pembrolizumab monotherapy. Among tested variables, TMB showed the strongest association with objective response (OR; P < 0.001) and PFS, by univariate (P < 0.001) and multivariate analysis (P < 0.01). Using log-rank statistics, the optimal predictive cut-point for TMB was estimated between 37 and 41 mutations/Mb. All 13 TMBhigh cases responded, while 6/9 TMBlow cases had progressive disease. The median PFS for TMBhigh has not been reached (median follow-up >18 months) while the median PFS for TMBlow was 2 months. A TMB of 37.4 mutations/Mb in a large MSI-H mCRC population (821/18, 140 cases; 4.5%) evaluated by NGS corresponded to the 35th percentile cut-point. CONCLUSIONS: TMB appears to be an important independent biomarker within MSI-H mCRC to stratify patients for likelihood of response to ICPIs. If validated in prospective studies, TMB may play an important role in guiding the sequencing and/or combinations of ICPIs in MSI-H mCRC.

Safety and clinical activity of atezolizumab in head and neck cancer: results from a phase I trial.

Background: Head and neck cancer (HNC) has a poor prognosis at advanced stages. Given the immunosuppressive tumor microenvironment in HNC, inhibition of the programmed death-ligand 1/programmed death-1 (PD-L1/PD-1) signaling pathway represents a promising therapeutic approach. Atezolizumab (anti-PD-L1) is efficacious against many tumor types. Here we report the clinical safety and activity from the HNC cohort of the phase Ia PCD4989g clinical trial. Patients and methods: Patients with previously treated, advanced HNC received atezolizumab i.v. every 3 weeks for 16 cycles, up to 1 year or until loss of clinical benefit. Patients were monitored for safety and tolerability and evaluated for response at least every 6 weeks. Baseline PD-L1 expression level and human papillomavirus (HPV) status were evaluated. Results: Thirty-two patients were enrolled; 7 patients (22%) had a primary tumor in the oral cavity, 18 (56%) in the oropharynx, 1 (3%) in the hypopharynx, 2 (6%) in the larynx, and 4 (13%) in the nasopharynx. Seventeen patients (53%) had ≥2 prior lines of therapy. Twenty-one patients (66%) experienced a treatment-related adverse event (TRAE), with three experiencing grade 3 TRAEs and one experiencing a grade 4 TRAE (per CTCAE v4.0). No grade 5 TRAEs were reported. Objective responses by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) occurred in 22% of patients, with a median duration of response of 7.4 months (range 2.8-45.8 months). Median progression-free survival was 2.6 months (range 0.5-48.4 months), and median overall survival was 6.0 months (range 0.5-51.6+ months). Responses showed no association with HPV status or PD-L1 expression level. Conclusions: In this heavily pre-treated advanced HNC cohort, atezolizumab had a tolerable safety profile and encouraging activity, with responses observed regardless of HPV status and PD-L1 expression level. These findings warrant further investigation of atezolizumab in HNC. ClinicalTrials.gov number: NCT01375842.

Cabozantinib in hepatocellular carcinoma: results of a phase 2 placebo-controlled randomized discontinuation study.

Background: Cabozantinib, an orally bioavailable inhibitor of tyrosine kinases including MET, AXL, and VEGF receptors, was assessed in patients with hepatocellular carcinoma (HCC) as part of a phase 2 randomized discontinuation trial with nine tumor-type cohorts. Patients and methods: Eligible patients had Child-Pugh A liver function and ≤1 prior systemic anticancer regimen, completed ≥4 weeks before study entry. The cabozantinib starting dose was 100 mg daily. After an initial 12-week cabozantinib treatment period, patients with stable disease (SD) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0 were randomized to cabozantinib or placebo. The primary endpoint of the lead-in stage was objective response rate (ORR) at week 12, and the primary endpoint of the randomized stage was progression-free survival (PFS). Results: Among the 41 HCC patients enrolled, the week 12 ORR was 5%, with 2 patients achieving a confirmed partial response (PR). The week 12 disease control rate (PR or SD) was 66% (Asian subgroup: 73%). Of patients with ≥1 post-baseline scan, 78% had tumor regression, with no apparent relationship to prior sorafenib therapy. Alpha-fetoprotein (AFP) response (>50% reduction from baseline) occurred in 9 of the 26 (35%) patients with elevated baseline AFP and ≥1 post-baseline measurement. Twenty-two patients with SD at week 12 were randomized. Median PFS after randomization was 2.5 months with cabozantinib and 1.4 months with placebo, although this difference was not statistically significant. Median PFS and overall survival from Day 1 in all patients were 5.2 and 11.5 months, respectively. The most common grade 3/4 adverse events, regardless of attribution, were diarrhea (20%), hand-foot syndrome (15%), and thrombocytopenia (15%). Dose reductions were utilized in 59% of patients. Conclusions: Cabozantinib has clinical activity in HCC patients, including objective tumor responses, disease stabilization, and reductions in AFP. Adverse events were managed with dose reductions. Trial registration number: NCT00940225.

Ramucirumab combined with FOLFOX as front-line therapy for advanced esophageal, gastroesophageal junction, or gastric adenocarcinoma: a randomized, double-blind, multicenter Phase II trial.

BACKGROUND: We report the first randomized, Phase II trial of ramucirumab, an anti-vascular endothelial growth factor receptor-2 monoclonal antibody, as front-line therapy in patients with advanced adenocarcinoma of the esophagus or gastric/gastroesophageal junction (GEJ). PATIENTS AND METHODS: Patients from the USA with advanced esophageal, gastric, or GEJ adenocarcinoma randomly received (1:1) mFOLFOX6 plus ramucirumab (8 mg/kg) or mFOLFOX6 plus placebo every 2 weeks. The primary end point was progression-free survival (PFS) with 80% power to detect a hazard ratio (HR) of 0.71 (one-sided α = 0.15). Secondary end points included evaluation of response and overall survival (OS); an exploratory ramucirumab exposure-response analysis was undertaken. RESULTS: Of 168 randomized patients, 52% of tumors were located in the stomach/GEJ and 48% in the esophagus. The trial did not meet the primary end point of PFS [6.4 versus 6.7 months, HR 0.98 (95% confidence interval 0.69-1.37)] or the secondary end point of OS (11.7 versus 11.5 months) in the intent-to-treat (ITT) population. Objective response rates (45.2% versus 46.4%) were similar between arms. Most Grade ≥3 toxicities did not differ significantly between arms, yet premature discontinuation of FOLFOX and ramucirumab (for reasons other than progressive disease) was more common among ramucirumab- versus placebo-treated patients. In an exploratory analysis that censored for premature discontinuation, the HR for PFS favored the ramucirumab arm (HR 0.76), particularly in patients with gastric/GEJ cancer. An exploratory exposure-response analysis indicated that patients with higher ramucirumab exposure had longer OS. CONCLUSION: The addition of ramucirumab to front-line mFOLFOX6 did not improve PFS in the ITT population. CLINICALTRIALSGOV IDENTIFIER: NCT01246960.

A phase Ib/II dose expansion study of subcutaneous sasanlimab in patients with locally advanced or metastatic non-small-cell lung cancer and urothelial carcinoma.

BACKGROUND: Sasanlimab is an antibody to the programmed cell death protein 1 receptor. We report updated data of subcutaneous sasanlimab in non-small-cell lung cancer (NSCLC) and urothelial carcinoma dose expansion cohorts from a first-in-human phase Ib/II study. PATIENTS AND METHODS: Patients were ≥18 years of age with NSCLC or urothelial carcinoma, and no prior immunotherapies, who progressed on or were intolerant to systemic therapy, or for whom systemic therapy was refused or unavailable. Patients received subcutaneous sasanlimab at 300 mg every 4 weeks (q4w). Primary objectives were to evaluate safety, tolerability, and clinical efficacy by objective response rate (ORR). RESULTS: Sixty-eight and 38 patients with NSCLC and urothelial carcinoma, respectively, received subcutaneous sasanlimab. Overall, sasanlimab was well tolerated; 13.2% of patients experienced grade ≥3 treatment-related adverse events. Confirmed ORR was 16.4% and 18.4% in the NSCLC and urothelial carcinoma cohorts, respectively. ORR was generally higher in patients with high programmed death-ligand 1 (PD-L1) expression (≥25%) and high tumor mutational burden (TMB; >75%). In the NSCLC and urothelial carcinoma cohorts, median progression-free survival (PFS) was 3.7 and 2.9 months, respectively; corresponding median overall survival (OS) was 14.7 and 10.9 months. Overall, longer median PFS and OS correlated with high PD-L1 expression and high TMB. Longer median PFS and OS were also associated with T-cell inflamed gene signature in the urothelial carcinoma cohort. CONCLUSIONS: Subcutaneous sasanlimab at 300 mg q4w was well tolerated with promising clinical efficacy observed. Phase II and III clinical trials of sasanlimab are ongoing to validate clinical benefit. Subcutaneous sasanlimab may be a potential treatment option for patients with NSCLC or urothelial carcinoma.