Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2019

Avelumab treatment of metastatic Merkel cell carcinoma (mMCC): updated findings from Australian patients enrolled in an expanded access program (EAP) (#348)

Shahneen Sandhu 1 , Vijay Kasturi 2 , Alex Guminski 3 , Christopher Steer 4 , Victoria Atkinson 5 , Ina Nordman 6 , Peter Tobin 7 , Josh Reed 2 , Nuno Costa 8 , Belinda Lee 9 10
  1. Peter MacCallum Cancer Centre, Melbourne, Australia
  2. EMD Serono, Inc, Billerica, MA, United States
  3. University of Sydney and Royal North Shore and Mater Hospitals, Sydney, NSW, Australia
  4. Border Medical Oncology, Albury Wodonga Regional Cancer Centre, Albury , NSW, Australia
  5. University of Queensland, Princess Alexandra Hospital, Brisbane, Queensland, Australia
  6. Calvary Mater Newcastle, Waratah, NSW, Australia
  7. Merck Serono, Singapore
  8. Pfizer Inc., New York, United States
  9. Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
  10. Royal Melbourne Hospital, Parkville, VIC, Australia

Aims: Avelumab is an anti–PD-L1 immune checkpoint inhibitor that has been approved for the treatment of mMCC in various countries, including Australia, based on the results of the JAVELIN Merkel 200 trial. We report updated real-world data for avelumab treatment in Australian patients with mMCC.

 

Methods: Patients eligible for the avelumab EAP (NCT03089658) had mMCC and progressive disease (PD) on/after chemotherapy or were ineligible for chemotherapy or participation in clinical trials. Unlike JAVELIN Merkel 200, patients were permitted to have an ECOG performance status (PS) ≥2, treated brain metastases, or immunosuppressive conditions (with medical approval). Patients received avelumab 10 mg/kg IV Q2W until PD or unacceptable toxicity. A 3-month supply was provided initially, with resupply allowed following complete response (CR), partial response (PR), stable disease (SD), or clinical benefit per physician assessment. Data are reported from the EAP database; no central imaging was obtained.

 

Results: 74 patients with mMCC were approved to receive treatment within the avelumab EAP in Australia. Median age was 75.8 years (range, 46-95); 67.6% were male; ECOG PS was 0-1 in 91.9% and 2 in 4.1% (not reported in 4.1%). The objective response rate among 28 evaluable patients was 44.7%, including CR in 21.1% and PR in 23.7%; 34.2% had SD as best response. Median duration of treatment in patients with CR/PR was 7.4 months (range, 2.0-12.9). Enrollment in the EAP is now closed after regulatory approval of avelumab in Australia.

 

Conclusions: In a real-world population of Australian patients with mMCC, including some patients who were ineligible for chemotherapy or clinical trial participation, treatment responses observed support previously reported trial findings from JAVELIN Merkel 200 and indicate a clinically meaningful efficacy benefit compared with historical chemotherapy in treatment-refractory mMCC.