Abstract 4554: Assessment of the efficacy and safety of checkpoint inhibitors in the treatment of solid-tumor malignancies in a community cancer hospital

Abstract

Abstract Introduction: High dose chemotherapy, radiation, and/or surgical resection have historically been the standard therapy for patients with progressive malignancies. However, promising studies have shown immunotherapy may improve overall survival and reduce tumor burden in advanced disease. Checkpoint inhibitors, such as PD-1 inhibitors pembrolizumab and nivolumab and PD-L1 inhibitor atezolizumab, are approved for use in several solid tumors, but the response to these agents has been limited. This study was designed to identify predictors for the therapeutic response to immunotherapy agents in a community cancer hospital. Procedures: A retrospective review using the electronic medical record system was done to identify 43 patients treated with immunotherapy at Avera Cancer Institute. The inclusion criteria included patients who had solid organ malignancies, received checkpoint inhibitor-based immunotherapy between May 31, 2014 and May 31, 2017, and completed next generation sequencing of tumor DNA. The exclusion criteria included patients who were less than eighteen years of age, pregnant, or received care in an outreach clinic when records were not available. Data obtained from the records included age, sex, diagnosis, treatment history, immunotherapy agent used, start and end date of immunotherapy agent, clinical outcome, pathology results, adverse reactions, and next generation sequencing results of tumor DNA. The collected data was assessed for patient characteristics and biomarkers that predicted responses to immune checkpoint blockade in solid tumors. Disease progression was assessed in correspondence with the response evaluation criteria in solid tumors guidelines. Results: A total of 43 patients were included, 14 male and 29 female. The median patient age was 66 years old. The main malignancies included were, breast (11 patients), lung (10 patients), and ovarian (7 patients). On average, the patients were treated with three previous lines of therapy before receiving immunotherapy treatment. The most common immunotherapy agent was pembrolizumab, with 28 of the patients receiving this, followed by 14 patients treated with nivolumab and one treated with atezolizumab. The median time patients on immunotherapy was 118 days. Patients with longer duration of immunotherapy, fewer previous treatment lines, and higher tumor mutational burden (TMB) had the best response to checkpoint inhibitors. Conclusions: The predictive biomarkers found in this study can be used to assist in patient selection for immunotherapy in the clinical setting, including TMB and the number of lines of previous therapy. Further studies will continue to find predictors of non-response and hyperprogressors. We hope to further evaluate patients who experienced a durable response to create new hypotheses about indicators of response. Citation Format: Rachel Elsey, Nathan Smith, April Lick, Lauren Metzger, Casey Williams, Brian Leyland-Jones, Ping Ye. Assessment of the efficacy and safety of checkpoint inhibitors in the treatment of solid-tumor malignancies in a community cancer hospital [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4554.