OBJECTIVES

Merkel cell carcinoma (MCC) is a rare and aggressive form of skin cancer, with no US FDA approved treatment until 2017. Avelumab, a PD-L1 antibody, became the first FDA approved treatment for metastatic MCC (mMCC) in March 2017. Treatment guidelines from the National Comprehensive Cancer Network (NCCN) recommend CPIs including avelumab, nivolumab and pembrolizumab as treatment options for mMCC. This study is to assess the real-world treatment patterns and outcomes of mMCC patients receiving CPIs and chemotherapies.

METHODS

An observational study was conducted from March 1, 2015-December 31, 2017 using the Premier Healthcare Database (PHD). mMCC patients age ≥ 12 were identified by ICD-9/10 codes and included if the initial treatment received during the study period was a CPI or chemotherapy per NCCN guidelines. The initial treatment date served as the index date.

RESULTS

Thirty-seven mMCC patients received CPIs and 38 chemotherapy, with 84% of patients receiving platinum based chemotherapy. Baseline characteristics were similar between the CPI and chemotherapy group for age, race and Charlson comorbidity index, while the CPI group trended towards having more males and more patients with commercial insurance. More CPI patients stayed on treatments than the chemotherapy group at day 30 (68% vs. 53%, p<0.001), 60 (54% vs. 42%, p<0.001) and 90 (46% vs. 26%, p<0.001). By day 90, 74% of patients who started on chemotherapy switched to a different treatment in comparison to 54% of CPI patients (p<0.001). A comprehensive list of 47 adverse events commonly associated with CPIs and chemotherapies were studied, and the average number of AEs was 1.2±1.5 for the CPI group and 1.6±1.7 for the chemotherapy group (p=0.35).

CONCLUSIONS

The availability of CPIs for mMCC patients is practice changing. CPI patients treated in hospital-based settings had longer time-on-treatment, less treatment switching, and trended towards fewer adverse events vs. chemotherapy.