Merkel cell carcinoma responds to immunotherapy

“Additionally, the pIL-12/electroporation treatment led to objective clinical responses in metastatic MCC,” Dr. Bhatia reported.

Among the three patients with locally advanced disease, one had a pathologic complete response and remains free of recurrence more than 6 months later. Another patient has been recurrence free for more than 3 years. The third patient was recurrence free for 9 months before developing progressive disease.

Among the 12 patients with metastatic disease, 3 responded to treatment and 1 achieved stable disease, while 8 (52%) progressed.

The injections led to regression not only of treated lesions, but also of clearly distinct noninjected MCC tumors. The proportion of treated lesions with major (more than 30%) regression was 44%. Among 10 patients with at least one distant lesion, 30% of noninjected distant lesions regressed.

“We believe this approach warrants further exploration in MCC, perhaps in combination with emerging systemic therapies, such as anti-PD-1/PD-L1 agents,” Dr. Bhatia said.

Dr. Nghiem and Dr. Bhatia had no relevant disclosures. In the IL-12 study, some investigators have financial relationships with OncoSec Medical, which manufactures the study drug.