EFFECTIVENESS OF PEMBROLIZUMAB AS MONOTHERAPY OR IN COMBINATION WITH CHEMOTHERAPY FOR RECURRENT OR METASTATIC HEAD AND NECK SQUAMOUS CELL CARCINOMA (RMHNSCC) PATIENTS: A COHORT OF 65 PATIENTS

Pembrolizumab as monotherapy (P) or in combination with chemotherapy (P+C) was stablished as standard of care in first-line therapy for recurrent or metastatic head and neck squamous cell carcinoma (rmHNSCC), following the results of the phase III Keynote-048. After three years of approval by ANVISA, there are still no data on effectiveness in Brazil. Aim: The objective of this study was to assess the real-world overall survival (rwOS) of patients with rmHNSCC treated between 2019 and 2022 with first-line P or P+C. Methods: All adult patients who started treatment with P or P+C were selected from data lake of a Brazilian private oncology group. rwOS was defined as the date of starting P or P+C to the date of death. Epidemiological characteristics and treatment pattern data were recovered from medical records. Kaplan-Meier method was used for survival analysis and descriptive statistics were used for epidemiological and clinical data analysis. The cutoff date for analysis was August 26, 2022. The study was approved by the local IRB (CAAE 60840022.2.0000.0227). Results: A total of 65 patients were included in the study, most of them from Southwest region (70.8%). The median age was 70 years old (30-96), 60% of patients were male, 58% received P and 42% P+C. The most common primary tumor was oral cavity (38.5%), followed by oropharynx (26.2%) and larynx (16.9%). With a median follow-up of 2.1 months, the median rwOS was 9.57 months (95%CI, 8.27 to NR) for all patients, 8.87 months for those treated with P and 15.43 (95%CI, 13.00 to NR) for those treated with P+C. Conclusion: The results observed here in our study are similar to those demonstrated in the phase III study Keynote-048, which led to the approval of pembrolizumab in the first-line treatment of rmHNSCC patients. Pembrolizumab as monotherapy or combined with chemotherapy are reasonable options for rmHNSCC. The choice between the two options should be tailored considering performance status, total volume of disease and PD-L1 combined positive score (CPS).