Avelumab and Merkel Cell Carcinoma: Examining the Causation Question

From General Health to Specific Exposure Concerns

For decades, public health communication has centered on general wellness principles, emphasizing lifestyle factors such as diet, exercise, and routine screenings to mitigate disease risk. This broad framework has served as the foundation for understanding how environmental and behavioral exposures influence long-term health outcomes. Within this legacy, the role of pharmaceutical agents has been considered primarily in therapeutic terms—medications are evaluated for their intended benefits, with side effects framed as secondary considerations. However, as medical science advances, the boundary between therapeutic intervention and unintended exposure becomes increasingly nuanced. The case of Avelumab, a monoclonal antibody approved for the treatment of Merkel cell carcinoma, illustrates this complexity. Originally introduced as a targeted immunotherapy, Avelumab’s clinical profile has prompted scrutiny beyond its direct application. Specifically, questions have emerged regarding whether exposure to this agent—whether through occupational handling, manufacturing processes, or environmental contamination—could itself be linked to the very condition it is designed to treat. This pivot from general health context to a specific exposure concern requires a careful reexamination of risk assessment frameworks. Rather than focusing on mechanistic pathways, the transition here is conceptual: moving from a population-level wellness perspective to a focused inquiry into how a therapeutic compound may, under certain conditions, represent an occupational hazard. This shift underscores the need for vigilance in settings where pharmaceutical agents are produced, handled, or disposed of, demanding that legacy health models adapt to accommodate emerging exposure paradigms.

Avelumab: Mechanism and Approved Use

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 is approved in the USA, the EU, 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/29799096/). Approval was based on the phase II JAVELIN Merkel 200 trial, in which confirmed objective responses were observed in approximately one-third of patients with chemotherapy-refractory metastatic MCC (https://pubmed.ncbi.nlm.nih.gov/29799096/). Avelumab is the first therapeutic agent specifically approved for this indication and is approved independent of line of treatment (https://pubmed.ncbi.nlm.nih.gov/29799096/). Merkel cell carcinoma is a rare but highly aggressive skin cancer with neuroendocrine differentiation, associated with chronic exposure to ultraviolet light and the Merkel cell polyoma virus (https://pubmed.ncbi.nlm.nih.gov/35877101/). The incidence of MCC is increasing, and it is associated with high rates of recurrence and mortality (https://pubmed.ncbi.nlm.nih.gov/35877101/). Immune checkpoint inhibitors, including avelumab, have significantly improved treatment outcomes in metastatic disease, with response rates to PD-1/PD-L1 inhibition of up to 62% (https://pubmed.ncbi.nlm.nih.gov/36450381/). Despite these advances, approximately 50% of patients with advanced MCC treated with immune checkpoint inhibitors progress on therapy (https://pubmed.ncbi.nlm.nih.gov/35877101/).

Causation Analysis: Avelumab as Treatment, Not Cause

The causal relationship between avelumab and Merkel cell carcinoma is not one of induction but of therapeutic targeting. Avelumab is used to treat MCC, not to cause it. The evidence indicates that avelumab is an approved therapy for metastatic MCC, and its use is associated with immune-related adverse events due to overactivation of the immune system (https://pubmed.ncbi.nlm.nih.gov/31543781/). For example, a case report described hypercalcemia secondary to reactivation of sarcoidosis in a patient with metastatic MCC on avelumab, which was managed with corticosteroids, and avelumab therapy was safely continued (https://pubmed.ncbi.nlm.nih.gov/31543781/). This illustrates that while avelumab can trigger immune-related adverse events, it does not cause MCC. Mechanistic pathways linking avelumab to MCC are not relevant in a causation sense, as avelumab is a treatment for the disease. However, the mechanism of action involves blocking PD-L1, thereby enhancing T-cell activity against tumor cells. In patients with MCC, this can lead to tumor regression, but also to immune-related adverse events. The evidence does not support a pathway by which avelumab causes MCC; rather, it is used to treat existing MCC.

Risk Considerations and Patient Outcomes

Risk considerations for affected patients include the adequacy of warnings regarding avelumab and MCC. The evidence shows that avelumab is approved for MCC treatment, and its prescribing information includes warnings about immune-related adverse events. However, the evidence does not indicate that avelumab causes MCC. For patients with MCC, the risk is that approximately 50% may not respond to avelumab or may progress on therapy (https://pubmed.ncbi.nlm.nih.gov/35877101/). For avelumab-refractory patients, treatment options are limited, but combination therapy with ipilimumab and nivolumab has shown activity in this setting. In a multicenter study, three out of five patients with avelumab-refractory MCC responded to combined ipilimumab and nivolumab according to RECIST 1.1 (https://pubmed.ncbi.nlm.nih.gov/33439294/). Another study reported that immune checkpoint inhibition has significantly improved treatment outcomes in metastatic MCC, with response rates to PD-1/PD-L1 inhibition of up to 62% (https://pubmed.ncbi.nlm.nih.gov/36450381/). Causation-related considerations for affected patients focus on the timeline between exposure and documented harm. Since avelumab is a treatment for MCC, exposure occurs after diagnosis. The timeline of harm, such as disease progression or immune-related adverse events, is documented during treatment. For example, in the JAVELIN Merkel 200 trial, responses were observed in approximately one-third of patients, indicating that harm (lack of response or progression) occurs in a majority of patients (https://pubmed.ncbi.nlm.nih.gov/29799096/). The evidence does not suggest a causal link between avelumab and the development of MCC; rather, it is a therapeutic agent for an existing condition.

Summary of Evidence

In summary, the evidence supports that avelumab is an effective treatment for metastatic MCC, but it does not cause the disease. The risk for patients includes the possibility of non-response or progression, as well as immune-related adverse events. The adequacy of warnings is reflected in the approved labeling, which includes information on immune-related adverse events. The timeline between exposure and harm is during treatment, with outcomes documented in clinical trials and case reports. References: (https://pubmed.ncbi.nlm.nih.gov/33439294/), (https://pubmed.ncbi.nlm.nih.gov/29799096/), (https://pubmed.ncbi.nlm.nih.gov/36450381/), (https://pubmed.ncbi.nlm.nih.gov/31543781/), (https://pubmed.ncbi.nlm.nih.gov/35877101/).

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 (MCC), not a cause. It is an immune checkpoint inhibitor approved for metastatic MCC. The evidence shows it targets existing cancer cells, and there is no causal link to developing MCC.

What are the risks of Avelumab treatment for MCC?

Risks include immune-related adverse events due to immune system overactivation, and approximately 50% of patients may not respond or may progress on therapy. For refractory cases, combination therapy with ipilimumab and nivolumab has shown some activity.

Does submitting information create an attorney-client relationship?

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

Information Registry: individuals with documented Avelumab exposure and a confirmed Merkel cell carcinoma diagnosis may request an independent eligibility review. [Begin Assessment]

References

Request a Free Case Review

This page is for educational and informational purposes only and is not medical or legal advice. Consult a licensed professional for case-specific guidance.