Pan-cancer (ca) analysis of the safety and efficacy of immune checkpoint inhibitors (ICI) in patients (pts) living with HIV (PLWH): Results from the international CATCH-IT consortium.

2649 Background: PLWH and ca are inadequately represented in clinical trials evaluating ICI especially in the setting of low CD4 counts (ct) and elevated HIV viral loads (VL). We assembled an international cohort of PLWH and ca treated with ICI to evaluate toxicity profiles and clinical outcomes. Methods: We retrospectively collected data on 204 PLWH and ca receiving ≥ 1 cycle of ICI between 2015-2021 at 14 academic medical centers in the US and Europe. Immune-related adverse events (irAEs) were graded per the Common Terminology Criteria for Adverse Events (CTCAE) V5.0. Baseline CD4 ct, CD8 ct and HIV VL were collected within 3 months (mo) of ICI initiation when available. Fisher’s exact test was performed to compare categorical variables. Median (med) Overall Survival (OS) and Objective Response Rate (ORR) were calculated for 186 pts treated in the metastatic (met) setting. Results: Among 204 PLWH treated with ICI, 174 (85%) were cis-gender males. 61 (31%) were Black and 34 (18%) were Hispanic/Latinx. Pts were treated with pembrolizumab (n=93), nivolumab (n=71), atezolizumab (n= 20), nivolumab and ipilimumab (n=13), durvalumab (n=6), or avelumab (n=1). Med number of prior lines of systemic therapy was 1 (range: 0-5). Among pts with available baseline data, 36/133 (27%) had CD4 ct <200 cells/µL while 12/136 (9%) had VL ≥400 copies/mL. irAEs of any grade occurred in 43 (21%) pts and 13 (7%) were grade ≥3 while 19 (9%) required steroids. Pts with CD4 ct <200 cells/µL experienced fewer irAEs than pts with CD4 ct ≥200 cells/µL (2/36 vs 26/97; p<0.01). The incidence of any grade irAEs was similar between pts with CD4/CD8 ratio <0.4 vs ≥0.4 (8/54 vs 18/72; p=0.16) and between pts with HIV VL ≥400 vs <400 copies/mL (1/12 vs 28/124; p=0.46). Clinical outcomes are shown in the table below. Among 29 pts with met non-small cell lung ca (NSCLC) with available CD4 ct, the ORR of pts with CD4 ct <200 cells/µL was 13% (95% CI:0-53) vs 38% (95% CI:18-62) in pts with CD4 ct ≥ 200 cells/µL (1/8 vs 8/21; p=0.38). Conclusions: In the largest dataset to our knowledge, we demonstrate tolerability and activity of ICI among PLWH regardless of CD4 ct and HIV VL levels. CD4 ct <200 cells/µL may be associated with a lower incidence of irAEs. An analysis of a larger cohort is underway. [Table: see text]