P50.01 A Year Experience With Atezolizumab Plus Chemotherapy For Small Cell Lung Cancer In Alberta, Canada

Abstract

The authors assessed the real-world effectiveness of newly approved regimen, atezolizumab plus carboplatin-etoposide (Atezo-CaE) for extensive stage (ES) small cell lung cancer (SCLC) in Alberta, Canada. Atezo-CaE is yet to be provincially funded for ES treatment but can be accessed through special access programs. Included in this study were confirmed ES patients treated with first-line Atezo-CaE at the tertiary and community cancer care centres in Alberta, Canada post FDA/ Health Canada approval (2019) up to the data cut-off date (September 1, 2020). Demographic and clinical data were extracted from the institutional Glans-Look Research Database. Any with active multiple malignancies and/or prior curative-intent treatment were excluded. Outcomes including overall response rate (ORR, RECIST v1.1), adverse events (CTCAE criteria v5), progression-free and overall survival were estimated using descriptive and Kaplan-Meier survival (Log-Rank) statistics. A priori statistical significance was p < 0.05. Analyses were performed using SPSS statistical software (version 25). There were 34 patients seen at the community care centres (18%) or academic tertiary institutions (82%). 53% were male, 24% had ECOG performance status ≥2 and the median age was 65 years. The median number of days from diagnosis to Atezo-CaE receipt was 40 (range: 14-128) days. 21% had no maintenance atezolizumab. In addition, 65% had radiotherapy treatment. 21% were still having ongoing atezolizumab treatment. The median duration of atezolizumab was 4.2 (range: 0.1-13.5) months. ORR was 62% with a median of 84 (range: 47-210) days time to best response. 18% have an ongoing response to atezolizumab. Disease progression was the commonest reason for 1L discontinuation while also accounting for the 2nd most common reason for no maintenance atezolizumab only after adverse events. Overall, progressive disease rate was 76%. The median duration of response was 98 (range: 35-635) days. 24% continued atezolizumab for ≥ 1 month past disease progression. 2L rate was 26%. The median progression-free and overall survival for all patients were 6 (95% CI: 4-8) and 11 (95% CI: 9-11) months while in those who received maintenance atezolizumab were 8 (p=0.01) and 13 (p<0.01) months respectively. Within a year of Atezo-CaE treatment for ES, there was 18% ongoing response to Atezo-CaE. The ORR (62 vs 60%), median treatment duration (4.2 vs 4.7 months) and overall survival outcomes (12.7 vs 12.3 months) appeared consistent in real-world versus clinical trial patients1. Future study to identify factors predicting Atezo-CaE treatment response and survival outcomes in SCLC is very much needed.