The formal discussant of the phase II SWOG S1512 trial was Zeynep Eroglu, MD, of the Department of Cutaneous Oncology at the Moffitt Cancer Center in Tampa, Florida. She congratulated Dr. Kendra and her coauthors for conducting a study in such a rare tumor. “I think we can say desmoplastic melanoma has one of the highest tumor response rates [to pembrolizumab] that we’ve seen in any cancer to anti–PD-1 therapy,” Dr. Eroglu told listeners.

Dr. Eroglu noted that studies are currently exploring combination immunotherapy for the first-line treatment of unresectable metastatic melanoma. She suggested that de-escalating therapy may be an option for patients with desmoplastic melanomas, “considering these very high response rates to PD-1 alone and given the elderly age of many of these patients. Perhaps PD-1–based combinations can be reserved for those rare patients with desmoplastic melanoma who are resistant to PD-1 alone,” she suggested.

Zeynep Eroglu, MD

In early-stage disease, the typical standard for desmoplastic melanoma is surgery. “But we know that surgery for desmoplastic melanoma can be quite morbid,” Dr. Eroglu noted. “These tumors tend to infiltrate deeply into a patient’s face or scalp and require extensive surgery—sometimes multiple surgeries for complete excision. Given how disfiguring surgery can be for patients with early-stage desmoplastic melanoma, I wonder if it’s possible in the future to de-escalate the surgical approach for patients with early-stage disease following neoadjuvant PD-1 therapy.”

Dr. Eroglu said that tumor samples from SWOG S1512 may help to determine why desmoplastic melanoma is so responsive to treatment with immunotherapy. It also may shed light on whether factors such as high tumor mutational burden, neurofibromatosis type 1–driven tumors, desmoplasia, and/or the tumor microenvironment may play a role. 

DISCLOSURE: Dr. Eroglu has served as a consultant to Array BioPharma, Eisai, Genentech, Natera, Novartis, OncoSec, Pfizer Canada Inc, and Regeneron and has received research funding from Boehringer Ingelheim, Pfizer, and Novartis.