Site Editor
Soo Park, MD
Soo Park, MD
Posted: Tuesday, November 26, 2024
New insights into the durability of response to immune checkpoint blockade in patients with advanced Merkel cell carcinoma, once treatment has been discontinued, have emerged. According to Andrew S. Brohl, MD, of Moffitt Cancer Center, Tampa, Florida, and colleagues, about half of their 45-patient cohort experienced disease progression within almost 1 year after cessation of immunotherapy. Their findings were published in the Journal for ImmunoTherapy of Cancer.
Specifically, 21 of the 45 patients (46.6%) experienced disease progression at a median of 11.3 months from treatment discontinuation. Some patients were less likely to experience disease progression than others: those who had originally exhibited a complete response (23.8% with progressive disease) vs those who had not (66.7%; P = .006); those who discontinued treatment electively (36.0%) vs those who stopped because of toxicity (60.0%; P = .14); and patients with viral-negative disease (30.8%) vs those with viral-positive disease (75.0%; P = .02). Of note, the patients in the viral-positive group initially had a higher rate of complete response than the viral-negative group.
All 45 patients included in this retrospective review had received at least one dose of anti–PD-L1 monotherapy for unresectable or metastatic disease, achieved stable disease or better, and then discontinued treatment for a reason other than disease progression. A total of 21 patients (46.6%) had a complete response to their initial immunotherapy, 23 (51.1%) had a partial response, and 1 (2.2%) had stable disease. A total of 25 patients (55.6%) discontinued immunotherapy electively; 20 (44.4%) discontinued it because of toxicity.
Of the 21 patients who experienced disease progression after immunotherapy, 16 were retreated with immune checkpoint blockade (12 single-agent; 4 combination). Of them, 15 were evaluable; 11 (73.3%) achieved an objective response. Although disease progression is a substantial risk in these patients after discontinuing immunotherapy, most patients maintain sensitivity to retreatment with the same drug class, concluded the investigators.
Disclosure: For full disclosures of the study authors, visit jitc.bmj.com.
Journal for ImmunoTherapy of Cancer
JNCCN Spotlights
