New Guidelines for Treating Metastatic Merkel Cell Carcinoma: Focus on Immunotherapy
Posted: Thursday, July 26, 2018
Although traditional treatment of metastatic Merkel cell carcinoma involves chemotherapy, resistance with subsequent rounds and poor progression-free survival have limited its effectiveness. Thus, new guidelines, published in the JNCCN–Journal of the National Comprehensive Cancer Network, include immunotherapy as a first-line approach. A review of clinical trials revealed novel immune checkpoint inhibitors were capable of reactivating cytotoxic T cells, neutralizing previously death-immune cancer cells.
“About half of patients treated with immunotherapies get nice, long-term responses, and this is changing the way we manage Merkel cell carcinoma” revealed Kelly G. Paulson, MD, PhD, of Fred Hutchinson Cancer Research Center, in a news release. Dr. Paulson, who coauthored a clinician’s guide to the advances in immunotherapy for this type of skin cancer with Shailender Bhatia, MD, emphasized the shift away from chemotherapy, as “it’s the wrong choice in many cases.”
Given that Merkel cell carcinoma is immunogenic, immunotherapy with PD-1/PD-L1 inhibitors (avelumab, pembrolizumab, nivolumab) and anti–CTLA-4 agents such as ipilimumab “leads to quick-onset, durable responses,” commented Drs. Paulson and Bhatia. In their review, key clinical trials of immune checkpoint inhibitors for metastatic Merkel cell carcinoma are explored, as are relevant issues to the clinical use of these therapies.
However, not all patients respond or benefit from immunotherapy. Research on the use of immunotherapy in the adjuvant setting for high-risk Merkel cell carcinoma, combination therapies to enhance response, as well as salvage therapies for those with immune checkpoint inhibitor–refractory disease is ongoing.