Merkel cell carcinoma ( MCC ) is a rare, aggressive skin cancer associated with poor survival outcomes in patients with distant metastatic disease ( mMCC ).
In an initial analysis from JAVELIN Merkel 200, a phase 2, prospective, open-label, single-arm trial in mMCC, Avelumab ( Bavencio ), a human anti-programmed death-ligand 1 ( PD-L1 ) monoclonal antibody, showed promising efficacy and a safety profile that was generally manageable and tolerable.
Researchers have reported the efficacy of Avelumab after 1 year or more of follow-up in patients with distant metastatic Merkel cell carcinoma that had progressed following prior chemotherapy for metastatic disease.
Patients received Avelumab 10 mg/kg by 1-h intravenous infusion every 2 weeks until confirmed disease progression, unacceptable toxicity, or withdrawal.
The primary endpoint was best overall response. Secondary endpoints included duration of response ( DOR ), progression-free survival ( PFS ), and overall survival ( OS ).
Patients ( n = 88 ) were followed for a minimum of 12 months.
The confirmed objective response rate was 33.0% ( 95% CI, 23.3%-43.8%; complete response: 11.4% ).
An estimated 74% of responses lasted 1 year or more, and 72.4% of responses were ongoing at data cutoff.
Responses were durable, with the median DOR not yet reached ( 95% CI, 18.0 months-not estimable ), and PFS was prolonged; 1-year PFS and OS rates were 30% ( 95% CI, 21%-41% ) and 52% ( 95% CI, 41%-62% ), respectively.
Median OS was 12.9 months ( 95% CI, 7.5-not estimable ).
Subgroup analyses suggested a higher probability of response in patients receiving fewer prior lines of systemic therapy, with a lower baseline disease burden, and with PD-L1-positive tumors; however, durable responses occurred irrespective of baseline factors, including tumor Merkel cell polyomavirus status.
In conclusion, with longer follow-up, Avelumab continues to show durable responses and promising survival outcomes in patients with distant metastatic Merkel cell carcinoma whose disease had progressed after chemotherapy. ( Xagena2018 )
Kaufman HL et al, J Immunother Cancer 2018; 6(1):7. doi: 10.1186/s40425-017-0310-x.