ASCO 2018: Neoadjuvant Nivolumab for Resectable Merkel Cell Carcinoma
Posted: Tuesday, July 10, 2018
Based on the results of the first trial of the anti–PD-1 antibody nivolumab used in the neoadjuvant setting for resectable Merkel cell carcinoma, when administered beginning 4 weeks before surgery, the drug “was safe and induced substantial radiologic and pathologic tumor regressions in 45% and 65% of patients, respectively,” according to Suzanne Louise Topalian, MD, of Baltimore’s Johns Hopkins Bloomberg/Kimmel Institute for Cancer Immunotherapy, and colleagues.
In their presentation of these findings from the phase I/II CheckMate 358 trial at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago (Abstract 9505), Dr. Topalian and her team wrote: “In some patients, this [treatment] obviated the need for more extensive surgery.”
A total of 25 patients with stage IIA-IV resectable Merkel cell carcinoma (median age, 70 years) participated in this trial, receiving nivolumab prior to surgery. Computed tomography scans of 20 patients, before and after treatment with nivolumab, showed that 16 had tumor regression; in 9 patients, the reduction was more than 30%. A total of 17 resections were evaluated for pathologic response by central investigator review; of them, 11 had major pathologic response (≤ 10% residual viable tumor cells), including 8 complete responses. Of the 21 patients followed after surgery, “all were progression-free at 6 months,” reported the researchers, whereas at 12 months, 2 had relapsed.
Merkel cell carcinoma tumors may be either positive or negative for the Merkel cell polyomavirus and may or may not express PD-L1. Significantly, major pathologic and radiologic responses occurred among all these tumor variants.
