Evaluation of real world treatment outcomes in patients with metastatic merkel cell carcinoma (MCC) following second line chemotherapy

Background

MCC is a rare, cutaneous, neuroendocrine tumor. MCC is an aggressive disease associated with frequent locoregional recurrences and visceral metastases, and a high mortality rate. This retrospective observational study aimed to assess treatment outcomes among second line (2L) or later chemotherapy in a real-world setting to better understand treatment pathways and prognosis in distant metastatic MCC patients (pts).

Methods

Data consisted of anonymized pt level information, extracted from a MCC specific registry in Europe. This registry contains data collected from 56 clinical sites in 3 countries (Germany: 53, Austria: 2, and Switzerland: 1). Endpoints described for the study population included objective response rate (ORR), progression-free survival (PFS), duration of response (DOR), durable response rate (DRR) and overall survival (OS). Best overall response was assessed using data from real-world practice provided by physicians to the registry, and thus based on routine radiology data and clinical judgment instead of Response Evaluation Criteria in Solid Tumors (RECIST) criteria.

Results

Of the total 971 pts with MCC in the registry, 326 pts were diagnosed with locally advanced or metastatic disease. Thirty four pts were identified with distant metastatic MCC and received 2nd or later line chemotherapy were included. Of these 34, 29 were eligible for the subgroup analyses of immunocompetent pts. Of the 5 immunocompromised pts, four had a B-cell chronic lymphocytic leukemia (B-CLL) and one received immunosuppressive treatment. Among all pts, 64.7% were male and the mean age of this cohort was 64.4 years. ORR to 2L or later chemotherapy was 8.8% (3/34). The median PFS from chemotherapy initiation was 3.0 months, median OS was 5.3 months and median DOR was 1.9 months. The 6-month DRR was 0% and PFS rate was 2.9%. Results in the immunocompetent pt subgroup were consistent with those in the entire population.

Conclusions

Both response rate and duration of response are very poor for 2L or later chemotherapy in distant metastatic MCC pts. Chemotherapy in the second line appears to be most useful for palliation in symptomatic pts. New treatment approaches with durable benefit are needed for these MCC pts.

Clinical trial identification

NA

Legal entity responsible for the study

EMD Serono and Merck KGaA

Funding

EMD Serono and Merck KGaAN/A –Authors wrote the abstract

Disclosure

J. Becker: Consultant/advisory for Merck Serono, BMS, Roche, CureVac, Rigontec, Lytex, Amgen. Speaker's Bureau for Merck Serono, Amgen. Research funding from BMS, Merck Serono. Travel expenses from Amgen and Merck Serono. E. Lorenz: Travel, accommodations, and/or expenses provided by Merck KGaA. G. Haas: Employee: IMS Health Stockholder: Sanofi. C. Helwig, D. Oksen, M. Bharmal: Employee of Merck KGaA. L. Mahnke: Employee of EMD Serono.