Avelumab and Merkel Cell Carcinoma Risk: What Studies Show

From General Health Education to Targeted Pharmacovigilance

For decades, general health and science communication has served as the foundation for public understanding of medical risks, emphasizing broad lifestyle factors and population-level disease prevention. This legacy framework has effectively guided individuals toward informed health decisions by contextualizing risk within everyday environments and behaviors. Within this tradition, occupational and environmental exposures have been addressed primarily through generalized warnings about chemical hazards or workplace safety, without delving into specific pharmaceutical or biological mechanisms. As the scope of health science has expanded, attention has increasingly turned to the role of specific therapeutic agents in disease development, particularly in the context of cancer risk. One area of growing interest involves the relationship between immunomodulatory drugs and subsequent malignancy. Among these, the programmed death-ligand 1 inhibitor Avelumab has been investigated for its potential association with Merkel cell carcinoma risk. This shift from general health education to focused pharmacovigilance represents a natural evolution of the field, moving from broad preventive advice to targeted scrutiny of exposure-outcome relationships. The transition from legacy health information to occupational exposure concern is therefore not a departure but an extension: applying the same principles of risk communication to a more specific, clinically relevant question. This pivot allows for a nuanced examination of how therapeutic interventions may influence cancer susceptibility, while maintaining the neutral, evidence-informed tone that has long characterized responsible health discourse.

Understanding Avelumab and Its Role in Merkel Cell Carcinoma

Avelumab (Bavencio) is a fully human IgG1 monoclonal antibody that functions as an immune checkpoint inhibitor by targeting programmed cell death ligand 1 (PD-L1) (https://pubmed.ncbi.nlm.nih.gov/29799096/). It has been approved in the United States, the European Union, and Japan for the treatment of metastatic Merkel cell carcinoma (MCC), a rare and aggressive neuroendocrine cutaneous malignancy with poor prognosis (https://pubmed.ncbi.nlm.nih.gov/33439294/; https://pubmed.ncbi.nlm.nih.gov/29799096/). Avelumab is the first therapeutic agent specifically approved for this indication and is approved for use independent of line of treatment (https://pubmed.ncbi.nlm.nih.gov/29799096/). The approval was based on the two-part, single-arm, phase II trial JAVELIN Merkel 200, in which confirmed objective responses were observed in approximately one-third of patients with chemotherapy-refractory metastatic MCC treated with avelumab (https://pubmed.ncbi.nlm.nih.gov/29799096/). Merkel cell carcinoma is associated with chronic exposure to ultraviolet light and the Merkel cell polyomavirus, with approximately 80% of cases caused by the human Merkel cell polyomavirus and the remaining 20% induced by UV light leading to mutations (https://pubmed.ncbi.nlm.nih.gov/35877101/; https://pubmed.ncbi.nlm.nih.gov/34445385/). The incidence rate of MCC is increasing, and the disease is associated with high rates of recurrence and mortality (https://pubmed.ncbi.nlm.nih.gov/35877101/).

Evidence on Avelumab and Merkel Cell Carcinoma Risk

Immune checkpoint inhibitors, including avelumab (anti-PD-L1) and pembrolizumab (anti-PD-1), offer durable responses and significant clinical benefit in advanced MCC, with response rates to PD-1/PD-L1 inhibition of up to 62% (https://pubmed.ncbi.nlm.nih.gov/36450381/; https://pubmed.ncbi.nlm.nih.gov/35877101/). However, approximately 50% of patients with advanced MCC treated with immune checkpoint inhibitors progress on therapy, and 50% of patients do not respond or develop immune-related adverse events due to diverse mechanisms such as down-regulation of MHC complexes or induction of anti-inflammatory cytokines (https://pubmed.ncbi.nlm.nih.gov/35877101/; https://pubmed.ncbi.nlm.nih.gov/34445385/). For patients who are refractory to avelumab, efficient and safe treatment options are lacking (https://pubmed.ncbi.nlm.nih.gov/33439294/). Studies have investigated the use of combined ipilimumab plus nivolumab in avelumab-refractory Merkel cell carcinoma. In a retrospective study at three different sites in Germany, clinical and molecular data of patients with metastatic MCC refractory to avelumab and later treated with combined ipilimumab plus nivolumab were collected and evaluated, with three out of five patients responding according to RECIST 1.1 (https://pubmed.ncbi.nlm.nih.gov/33439294/). A multicenter study of the prospective skin cancer registry ADOREG also examined ipilimumab plus nivolumab in avelumab-refractory MCC, noting that immune checkpoint inhibition has significantly improved treatment outcomes in metastatic disease (https://pubmed.ncbi.nlm.nih.gov/36450381/). A retrospective study of ipilimumab plus nivolumab in anti-PD-L1/PD-1 refractory MCC further highlighted that despite advances in systemic therapy, about 50% of patients with advanced MCC treated with immune checkpoint inhibitors progress on therapy (https://pubmed.ncbi.nlm.nih.gov/35877101/).

Causation Considerations: Avelumab as Treatment, Not Cause

Regarding causation-related considerations, avelumab is not a cause of Merkel cell carcinoma but is a treatment for it. The evidence indicates that avelumab is used to treat metastatic MCC, and the risk of developing MCC is not associated with avelumab exposure. Instead, the risk of MCC is linked to Merkel cell polyomavirus infection and UV light exposure (https://pubmed.ncbi.nlm.nih.gov/35877101/; https://pubmed.ncbi.nlm.nih.gov/34445385/). The timeline between avelumab exposure and documented harm relates to immune-related adverse events that can occur during treatment, but these are not MCC itself. The adequacy of warnings regarding avelumab and MCC is reflected in its approved labeling for the treatment of metastatic MCC, and the evidence does not suggest that avelumab causes MCC. The mechanistic pathways linking avelumab to MCC are not causative; rather, avelumab acts as an immune checkpoint inhibitor to treat MCC by blocking PD-L1, which can enhance T-cell responses against the tumor (https://pubmed.ncbi.nlm.nih.gov/34445385/). The standard treatment of metastatic MCC with anti-PD-1/PD-L1 immune checkpoint inhibitors such as avelumab shows better overall response rates and longer duration of responses compared with conventional chemotherapy (https://pubmed.ncbi.nlm.nih.gov/34445385/). In summary, the evidence supports that avelumab is an effective treatment for metastatic Merkel cell carcinoma, with a significant proportion of patients responding to therapy. However, a substantial number of patients do not respond or experience progression, and immune-related adverse events are a known risk. The risk of developing MCC is not attributable to avelumab, but rather to viral and environmental factors. For patients who are refractory to avelumab, alternative immune checkpoint inhibitor combinations such as ipilimumab plus nivolumab may offer benefit, though data are limited to small studies.

Important Notice

This page is for educational and informational purposes only. It does not provide medical diagnosis, treatment, or legal advice. Consult licensed clinicians and qualified attorneys for case-specific decisions.

Frequently Asked Questions

Does avelumab cause Merkel cell carcinoma?

No, avelumab is a treatment for Merkel cell carcinoma, not a cause. The risk of developing MCC is linked to Merkel cell polyomavirus infection and UV light exposure, not to avelumab (https://pubmed.ncbi.nlm.nih.gov/35877101/; https://pubmed.ncbi.nlm.nih.gov/34445385/).

What is the evidence for avelumab's effectiveness in Merkel cell carcinoma?

Avelumab was approved based on the JAVELIN Merkel 200 trial, which showed objective responses in about one-third of patients with chemotherapy-refractory metastatic MCC (https://pubmed.ncbi.nlm.nih.gov/29799096/). Response rates to PD-1/PD-L1 inhibitors can reach up to 62% (https://pubmed.ncbi.nlm.nih.gov/36450381/).

Does submitting information create an attorney-client relationship?

No. Submission requests an initial records screening only and does not create an attorney-client relationship.

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