5710 - Avelumab for advanced Merkel cell carcinoma in the Netherlands; a nationwide survey

Background

Merkel cell carcinoma (MCC) is a rare, aggressive tumour of the skin associated with high recurrence rates and poor survival. Clinical trials have shown activity of various checkpoint inhibitors targeting programmed death-(ligand)-1 (PD-(L)1). Avelumab is currently the only PD-L1 inhibitor that has been approved in the Netherlands for advanced/metastatic MCC (mMCC). Here, we report the Dutch real-world efficacy data of avelumab in patients with mMCC.

Methods

All mMCC patients from 4 tertiary referral centres in the Netherlands from December 2016 were analysed. Patients were included in this analysis if they had received avelumab for mMCC, regardless of other previous lines of therapy. Patient data were collected retrospectively and followed up prospectively after initiation of data collection. Primary endpoints were response rate (RR) and duration of response (DOR) , secondary endpoints were progression free survival (PFS), overall survival (OS) and toxicity. Toxicity was evaluated according to CTCAE version 5.0.

Results

Forty-six patients received avelumab, of which 37 patients were evaluable for response (9 had not reached response evaluation, 1 died due to comorbidity). In 22 (59.5%) patients avelumab was first-line treatment. Median follow up time was 7.8 (IQR 3.7-10.1) months. RR was 59.5% (n = 22) with 21.6% (n = 8) of patients having a complete radiological response. Median DOR was 6.3 (IQR 3.0-12.5) months and 15 (40.5%) patients had ongoing response at time of data analysis. Median PFS was 12.2 (95% CI 3.3-21.1) months, median OS was not yet reached. In subgroup analysis no differences were found for the presence of visceral metastases at baseline or previous lines of therapy. Five (13.2%) patients experienced grade 3 toxicity, of which 2 (4.3%) patients discontinued avelumab. No grade 4-5 toxicity were seen.

Conclusions

In the Netherlands treatment with avelumab is increasingly used in first- and second-line treatment for mMCC. In this real-world cohort, RR, DOR, PFS and toxicity results were in line with results from clinical trials and show relatively high, durable responses in patients with mMCC, unaffected by the presence of visceral metastases or previous lines of therapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.