Rapid adoption of immunotherapy in community health systems, associated with changing treatment guidelines.

e18610 Background: In the quickly evolving landscape of developmental therapeutics, uptake of new standards of care is a critical issue. Community health systems (CHS) provide > 50% of cancer care in the US. Rapidly changing immunotherapy (IO) guidelines provide a window into changing practice patterns. This analysis describes how IO use has evolved within CHS. Methods: Patients (pts) selected were ≥ 18 years, diagnosed with advanced or metastatic NSCLC 2015-2020, with 2+ EHR encounters before 4/1/2021. Two sub cohorts were analyzed. Cohort 1: pts receiving IO in any line of therapy (L); first use of IO by L was assessed over time. Cohort 2: pts receiving any first L (1L) therapy; 1L use of IO, alone or with chemotherapy (IO combo), was assessed over time. Results: In cohort 1, IO use in 1L grew from 24% of all IO pts in 2016 to 93% in 2020, increasing from 33% in Q4 2016 to 62% in Q1 2017. In cohort 2, 1L therapy shifted from 4% of all pts receiving IO in 1L in 2016 to 59% in 2020, increasing from 6% in Q4 2016 to 24% in Q1 2017. Within IO 1L pts, IO combo use grew from 29% to 68% in 2020, increasing from 35% in Q1 2018 to 53% in Q2 2018. Conclusions: We observed two rapid shifts in care patterns. First, 1L IO use grew rapidly from Q4 2016 to Q1 2017, following 1L IO approval (10/2016). Second, 1L IO use shifted rapidly toward IO combo use from Q1 2018 to Q2 2018, coinciding with pivotal trial results and FDA priority review (4/2018), but preceding label expansion (8/2018). Two RWD analyses from independent oncology practices observed less substantial shifts during similar periods of time. These results demonstrate that CHS can rapidly adjust to evolving clinical evidence and associated changes in standards of care.[Table: see text]