Biomarker analyses investigating disease biology and associations with outcomes in the JAVELIN Merkel 200 trial of avelumab in metastatic Merkel cell carcinoma.

PURPOSE: Avelumab (anti-PD-L1) became the first approved treatment for metastatic Merkel cell carcinoma (mMCC) based on results from the phase 2 JAVELIN Merkel 200 trial. We report exploratory biomarker analyses from the trial. PATIENTS AND METHODS: Patients with mMCC (n=88) with or without prior first-line chemotherapy received avelumab 10 mg/kg every 2 weeks. Analyses included: somatic mutations, mutational signatures, and tumor mutation burden from paired whole exome sequencing; gene, gene set, and immune content from RNAseq profiles; tumor PD-L1 and CD8 status from immunohistochemistry; and CD8 status from digital pathology. RESULTS: Tumors positive for Merkel cell polyomavirus (MCPyV) were characterized by an absence of driver mutations and a low tumor mutational burden, consistent with previous studies. A novel MCPyV-specific host gene expression signature was identified. MCPyV+ tumors had increased levels of immunosuppressive M2 macrophages in the tumor microenvironment, which appeared to correlate with PD-L1 expression; high CD8+ T-cell density in these tumors did not predict response to avelumab. Conversely, in patients with MCPyV- tumors, higher CD8+ T-cell density appeared to be associated with response. Mutations in several genes were associated with treatment outcomes. Compared with tumors sampled before chemotherapy, tumors sampled after chemotherapy had downregulated gene signatures for immune responses, including reduced expression of IFN-γ-related pathways. Levels of activated dendritic cells in responding patients were higher in patients assessed after vs before prior chemotherapy. CONCLUSIONS: Exploratory analyses provide insights into mMCC biology and potential associations with response to avelumab. Chemotherapy seems to negatively modulate the immune microenvironment.

Avelumab in Combination With Cetuximab and Chemotherapy as First-Line Treatment for Patients With Advanced Squamous NSCLC.

Introduction: We present the results of a phase 2a trial of first-line avelumab (anti-programmed death-ligand 1 antibody) plus cetuximab (anti-EGFR antibody) in patients with advanced squamous NSCLC. Methods: Patients with recurrent or metastatic squamous NSCLC received avelumab 800 mg (d 1 and 8), cetuximab 250 mg/m2 (d 1) and 500 mg/m2 (d 8), cisplatin 75 mg/m2 (d 1), and gemcitabine 1250 mg/m2 (d 1 and 8) for four 3-week cycles, followed by avelumab 800 mg and cetuximab 500 mg/m2 every 2 weeks. The primary end point was the best overall response; the secondary end points were progression-free survival, duration of response, overall survival, and safety. Efficacy analyses were reported from an updated data cutoff. Results: A total of 43 patients were enrolled. The median follow-up was 6.6 months for the primary analyses and 9.2 months for the efficacy analyses. In the efficacy analyses, 15 patients had a confirmed partial response (objective response rate, 34.9% [95% confidence interval: 21.0%-50.9%]), and the median duration of response was 7.1 months (95% confidence interval: 4.2-12.5 mo). The median progression-free survival and overall survival were 6.1 months and 10.0 months, respectively. In the safety analyses (primary analysis), 38 patients (88.4%) had a treatment-related adverse event, of whom 24 (55.8%) had a grade 3 or higher treatment-related adverse event. Conclusions: The combination of avelumab + cetuximab and chemotherapy showed antitumor activity and tolerable safety; however, the ORR was not improved compared with those reported for current standards of care (NCT03717155).