1134P - Avelumab in metastatic Merkel cell carcinoma (mMCC): Conditional survival and long-term safety in patients treated for ≥1 or ≥2 years in JAVELIN Merkel 200

Background

Avelumab, an anti–PD-L1 antibody, was approved worldwide for the treatment of mMCC based on results from the JAVELIN Merkel 200 phase 2 trial (NCT02155647). In patients treated with first-line (1L) avelumab, 1-, 2- and 4-year overall survival (OS) rates were 60%, 49%, and 38%, respectively. In patients treated with second-line or later (2L+) avelumab, 1-, 2- and 5-year OS rates were 50%, 36%, and 26%, respectively. We report the probability of additional OS and safety in patients treated with avelumab for ≥1 or ≥2 years.

Methods

Eligible patients had histologically confirmed stage IV MCC and no prior systemic therapy for metastatic disease (1L cohort; part B) or disease progression following ≥1 prior line of chemotherapy (2L+ cohort; part A). Patients received avelumab every 2 weeks until confirmed disease progression, unacceptable toxicity, or withdrawal of consent.

Results

In 116 and 88 patients who received 1L or 2L+ avelumab, treatment duration was ≥1 year in 40 (34.5%) and 23 (26.1%), and ≥2 years in 22 (19.0%) and 13 (14.8%), respectively. Compared with the overall population, a higher proportion of patients with ≥2 years of treatment had an ECOG performance status of 0 (1L, 72.7% vs 62.1%; 2L+, 69.2% vs 55.7%) or PD-L1+ tumors (1L, 27.3 % vs 18.1%; 2L+, 76.9% vs 64.8%). In patients who received ≥1 year of treatment, the probability of surviving for an additional 1, 2, or 3 years, respectively, was 97.4%, 89.5%, and 75.2% in the 1L cohort, and 87.0%, 78.3%, and 69.6% in the 2L+ cohort. In patients who received ≥2 years of treatment, the probability of surviving for an additional 1 or 2 years, respectively, was 100% and 81.0% in the 1L cohort, and 92.3% and 84.6% in the 2L+ cohort. Among patients in both cohorts who were still receiving treatment, treatment-related adverse events of any grade or grade ≥3 occurred after 1 year in 74.6% and 19.0%, and after 2 years in 45.7% and 5.7%, respectively.

Conclusions

Patients with mMCC who received ≥1 or ≥2 years of avelumab treatment had a high probability of surviving for an additional ≥2 years. Long-term safety was consistent with previous analyses. These results further support avelumab as a standard of care for patients with mMCC.

Clinical trial identification

NCT02155647; June 4, 2014.

Editorial acknowledgement

Medical writing support was provided by Sophie Saunders of Nucleus Global.

Legal entity responsible for the study

Merck.

Funding

This study was sponsored by Merck (CrossRef Funder ID: 10.13039/100009945).

Disclosure

C. Lebbe: Financial Interests, Personal, Other, Honoraria: Amgen; Financial Interests, Personal, Advisory Board, Honoraria: Bristol Myers Squibb, Incyte, MSD, Novartis, Pfizer, Pierre Fabre, Roche; Financial Interests, Personal, Speaker, Consultant, Advisor: Amgen, Bristol Myers Squibb, MSD, Novartis, Roche; Financial Interests, Personal, Speaker’s Bureau: Amgen, Bristol Myers Squibb, Novartis, Roche; Financial Interests, Personal and Institutional, Research Funding: Bristol Myers Squibb, Roche; Financial Interests, Personal, Other, travel and accommodation expenses: Bristol Myers Squibb; Financial Interests, Personal, Other: Avantis Medical Systems. P. Nghiem: Financial Interests, Personal, Speaker, Consultant, Advisor: Almirall, Instil Bio, Merck, Pfizer, Rain Oncology. S. Bhatia: Financial Interests, Personal and Institutional, Research Funding: 4SC, Amphivena, Bristol Myers Squibb, Checkmate, Regeneron, Exicure, Incyte, Merck, MSD, Novartis, Nektar, OncoSec, Agenus; Financial Interests, Personal, Research Funding: Xencor; Financial Interests, Personal, Speaker, Consultant, Advisor: Bristol Myers Squibb, Incyte, Regeneron. L. Mortier: Financial Interests, Personal, Other, travel and accommodation: Bristol Myers Squibb, Novartis, Roche/Genentech. A.S. Brohl: Financial Interests, Personal, Speaker, Consultant, Advisor: Deciphera, Bayer. N. Jacob: Financial Interests, Personal, Full or part-time Employment: Merck. K. Tyroller: Financial Interests, Personal, Full or part-time Employment: EMD Serono Research & Development Institute, Inc, Billerica, MA, USA; Financial Interests, Personal, Stocks or ownership: Merck. J. Hoffman: Financial Interests, Personal, Full or part-time Employment: EMD Serono Research & Development Institute, Inc, Billerica, MA, USA; Financial Interests, Personal, Stocks or ownership: MSD, Pfizer, Merck. S.P. D'Angelo: Financial Interests, Personal, Speaker, Consultant, Advisor: Amgen, Merck, GSK, Immune Design, Incyte, MSD, Nektar; Financial Interests, Personal and Institutional, Research Grant: Amgen, Bristol Myers Squibb, Deciphera, Merck, Incyte, MSD, Nektar; Financial Interests, Personal, Other, travel and accommodation: Adaptimmune, Merck, Nektar.