Assessing Anti–PD-1 Therapy Efficacy After Complete Response in Melanoma
Posted: Wednesday, July 31, 2019
A second course of anti–PD-1 therapy was found to elicit minimal response in patients with unresectable melanoma, according to research presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 9513). “In this largest data set to knowledge of [melanoma patients] treated with a second course of anti–PD-1, [the] response rate was low, even in [patients] who had achieved a response initially,” concluded Allison Betof Warner, MD, PhD, of Memorial Sloan Kettering Cancer Center, and colleagues. Further study on the optimal duration of initial immunotherapy in this patient population is needed.
The retrospective study included 398 patients who had received at least one dose of anti–PD-1 therapy and had been followed for no more than 3 months after the end of treatment. A subset of this group received a second course of anti–PD-1 therapy within 3 months of initial treatment cessation. Following initial anti–PD-1 treatment, 102 patients had a complete response; of those patients, treatment cessation occurred due to achievement of complete response (n = 72), toxicity (n = 24), or unspecified reasons (n = 6). At an average follow-up of 22.6 months for survivors achieving a complete response, the estimated 3-year overall survival was 82.5%, the estimated treatment-free survival was 72.3%, and the median treatment duration was 9.4 months.
After a median time off treatment of 11.6 months, a second course of anti–PD-1 therapy was administered to 34 patients. The median treatment duration was 10.9 weeks. The outcomes of the second treatment course included 2 patients with complete responses, 3 with tumor shrinkage, 9 with stable disease, and 20 with progressive disease. Overall, 1 of the 8 patients who had previously achieved a complete response and 2 of the 13 patients who had previously experienced other degrees of tumor shrinkage responded to the second treatment.
Disclosure: The study authors’ disclosure information may be found at coi.asco.org.