PCN25 First Real-World Evidence of Immunotherapy in the Brazilian Public Health System: A Retrospective Study in Melanoma Patients Treated with Pembrolizumab

Abstract

Pembrolizumab is a PD-1 antibody-mediated inhibitor approved for metastatic melanoma (MM) treatment with proven evidence of increasing patient survival. Immunotherapy use is not yet a reality in the Brazilian public health system and there is no data outside clinical trials regarding the efficacy of pembrolizumab in MM patients. The objective of the present study was to assess the effectiveness of pembrolizumab in MM patients in a Brazilian, oncologic, philanthropic hospital. Among 155 patients diagnosed with MM between 2017 and 2020, 42 received at least one course of treatment with pembrolizumab. Demographic and clinical characteristics of patients and treatment outcomes were extracted from the hospital-based registry and analyzed by SPSS 20.0. Progression-free survival (PFS) and overall survival (OS) were analyzed. Cox regression was performed for PFS and OS using gender, age, presence of brain metastases, number of metastatic sites, lines of therapy, body mass index and BRAF status as covariates. The baseline profile of patients was: 59.5% were under 60 years of age at diagnosis; 54.8% were males and 54.8 were BRAF V600E–mutant; 64.3% of patients received pembrolizumab as first line therapy and 42.9% had more than 4 different metastasis sites. The median OS and PFS of pembrolizumab-treated patients were 14.9 and 4.5 months, respectively. Among patients with BRAF V600E–mutant, median OS was 14.9 months vs 18.1 months in BRAF wild-type patients (p=0.047). The median OS was 11.3 months among male and was not reached in female (p=0.028). No statistical difference was detected in the other covariates. This study provides the first real-world evidence on the effectiveness of pembrolizumab in MM patients in Brazil, confirming the clinical benefits of immunotherapy in the public health system, in which dacarbazine is currently the available standard of care treatment for MM despite not being effective in prolonging patient survival.