2018 ASCO: 2-Year Update of Pivotal JAVELIN Merkel 200 Trial Shows Continued Durable Responses With Avelumab
Updated efficacy and safety data from the international, multicenter JAVELIN Merkel 200 trial of avelumab (Bavencio) in patients with metastatic Merkel cell carcinoma were presented by Nghiem et al at the 2018 ASCO Annual Meeting (Abstract 9507).
2-Year Follow-up
At the 2-year follow-up update of the study, avelumab continues to demonstrate clinically meaningful durable responses and stable rates of progression-free and overall survival from previous analyses in patients who responded to this treatment. Clinical activity was observed across all patient subgroups, irrespective of programmed cell death ligand 1 (PD-L1) expression in tumor tissue or Merkel cell polyomavirus status. The safety profile for avelumab in this trial has not changed with longer follow-up and remains consistent with that observed in the overall JAVELIN clinical development program.
In JAVELIN Merkel 200—an open-label, single-arm, phase II study—patients with histologically confirmed metastatic Merkel cell carcinoma whose disease had progressed on or after chemotherapy administrated for distant metastatic disease received avelumab at 10 mg/kg intravenously every 2 weeks until disease progression or unacceptable toxicity. A total of 88 patients were followed for a median of 29.2 months (range = 24.8–38.1 months).
The confirmed overall response rate of 33% (95% confidence interval [CI] = 23.3%–43.8%; complete response in 11.4%) remained unchanged from previous analyses reported at both 1 year and 18 months. Responses remained ongoing in 19 of 29 patients who responded to treatment, including 12 patients whose duration of response exceeded 2 years. Durable responses led to stable rates of progression-free survival (29% at 12 months, 29% at 18 months, and 26% at 24 months). Median overall survival was 12.6 months (95% CI = 7.5–17.1) and the 2-year overall survival rate was 36% (50% at 12 months and 39% at 18 months).
With a minimum follow-up of 2 years, no new safety signals were identified for avelumab and the safety profile was consistent with prior reports. Sixty-seven patients (76.1%) had a treatment-related adverse event, 10 patients (11.4%) had a grade 3 or less treatment-related adverse event, and 20 patients (22.7%) had an immune-related adverse event. No treatment-related deaths occurred.
About JAVELIN Merkel 200
Patients in the JAVELIN Merkel 200 study were generally elderly (median age = 72.5 years, range = 33–88 years) and pretreated, with at least 1 line of chemotherapy (1 [59.1%], 2 [29.5%], or 3 or more [11.4%] previous treatments). Patients received avelumab at 10 mg/kg intravenously once every 2 weeks.
The protocol-defined analysis set for efficacy and safety consisted of all patients who received at least one dose of study treatment. The cutoff date for the planned primary analysis was 6 months after start of study treatment of the last patient.
The primary endpoint of the study was confirmed best overall response according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1 and assessed by an independent review committee. Secondary endpoints were duration of response, progression free survival, overall survival, response status by RECIST at 6 and 12 months, safety and tolerability, pharmacokinetics, and immunogenicity of avelumab.
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