Characteristics and outcomes of advanced melanoma patients with complete response and elective discontinuation of first-line anti-programmed death-1 monotherapy: A real-world multicentre observational cohort study.

Anti-programmed death-1 (anti-PD1) treatment has significantly improved outcomes of advanced melanoma with a considerable percentage of patients achieving complete response (CR). This real-world study analyzed the feasibility of elective anti-PD1 discontinuation in advanced melanoma patients with CR and evaluated factors related to sustained response. Thirty-five patients with advanced cutaneous or primary unknown melanoma with CR to nivolumab or pembrolizumab from 11 centers were included. Mean age was 66.5 years, and 97.1% had ECOG PS 0-1. 28.6% had ≥3 metastatic sites with 58.8% having M1a-M1b disease; 8.6% had liver and 5.7% had brain metastases. At baseline, 80% had normal LDH, and 85.7% had a neutrophil-to-lymphocyte ratio ≤3. 74.3% of patients had CR confirmed in PET-CT. Median duration of anti-PD1 was 23.4 months (range 1.3-50.5). 24 months after therapy discontinuation, 91.9% of patients were progression-free. Estimated PFS and OS at 36, 48, and 60 months from the start of anti-PD1 were 94.2%, 89.9%, 84.3%, and 97.1%, 93.3%, 93.3%, respectively. Antibiotics use after anti-PD1 discontinuation increased the odds of progression (OR 16.53 [95% CI 1.7, 226.03]). The study confirms the feasibility of elective anti-PD1 discontinuation in advanced melanoma patients with CR and favorable prognostic factors at baseline.

Unexpected pure red series aplastic anemia secondary to pembrolizumab treatment: a case report and literature review.

Pembrolizumab is a treatment that has shown a survival benefit in patients with metastatic melanoma. Programmed death receptor 1 inhibitors are new therapeutic agents that produce clinical responses with a more manageable profile of adverse effects compared to chemotherapy. The most frequent adverse effects include fatigue, rash, myalgia, pyrexia and cough, with less frequent occurrence of immune-mediated adverse reactions such as colitis, pneumonitis, hepatitis and encephalitis. Immune-related hematological toxicities have been poorly described. Here we present the case of a patient with metastatic melanoma who develops pure red series aplasia after almost 3 years of treatment with pembrolizumab. To our knowledge, this is the first case of aplastic anemia during treatment with pembrolizumab, with some peculiarities compared to the published cases in the literature.