Aims: Avelumab—a human anti–PD-L1 IgG1 monoclonal antibody—showed clinical activity and a manageable safety profile in the phase 2 JAVELIN Merkel 200 trial (NCT02155647), leading to its approval in multiple countries. Here, we describe real-world experience with avelumab in Australian patients with mMCC.
Methods: Patients participating in the EAP (NCT03089658) had stage IV mMCC and PD on/after chemotherapy or were ineligible for chemotherapy or participation in clinical trials. In contrast to JAVELIN Merkel 200, with medical approval, patients could have ECOG ≥2, treated brain metastases, or immunosuppressive conditions. Patients received avelumab 10 mg/kg IV Q2W until PD or unacceptable toxicity. A 3-mo supply was provided; resupply was allowed for patients with complete response (CR), partial response (PR), stable disease, or clinical benefit per physician assessment. No central imaging was obtained.
Results: As of 2 April 2018, among 508 requests for avelumab across 37 countries, 61 requests were received in Australia: 54 were approved and 7 were medically rejected. Median age was 77 y (range, 45-95) and 66.7% of patients were male. 49 patients have received avelumab. Among 34 patients on treatment >3 mo, physician-assessed objective responses were observed in 8 of 16 evaluable patients (23.5%; 4 CR [11.8%] and 4 PR [11.8%; including 1 patient with HIV]); 18 patients (52.9%) had either unevaluable tumors or no data reported. Median time to response was 49 d (range, 28-140). No new safety signals were reported. The EAP is ongoing but closing in 2018 as required post-approval (US closed in 2017).
Conclusions: The avelumab EAP provides an alternative treatment option for patients with mMCC with PD on/after chemotherapy or are ineligible for either chemotherapy or clinical trials. In a real-world setting, avelumab showed efficacy and safety consistent with JAVELIN Merkel 200.