Nassar, Amin

2653 Background: Given underlying differences in the tumor microenvironment across metastatic sites, ICIs demonstrate variable efficacy depending on sites of met involvement. Data on the safety and outcomes of pts on ICIs with cardiac mets are limited. Methods: In an international multi-center retrospective study, pts with solid tumors and baseline mets to the heart who had received ≥1 cycle of ICIs were included. Immune-related adverse events (irAEs) were graded per CTCAE v5.0. Objective response rates (ORR) were evaluated by RECIST1.1 when available. Median overall survival (mOS) and median progression-free survival (mPFS) were calculated from time of ICI initiation using the Kaplan-Meier method. Results: 110 pts across 20 institutions were identified with a median follow-up of 36 (95% CI 26-51) months. Melanoma (38%, n=42) and non-small cell lung cancer (NSCLC, 24%, n=26) were the most common cancers. Median age at ICI initiation was 65 (IQR: 59-75) years and 29% (n=26) received combination ICI therapy with anti-PD1 and anti-CTLA4. Overall, 62% (n=68) received ICIs as 1st line. The mets were mostly located in the atria (37%, n=41) and ventricles (35%, n=39). At ICI initiation, 21% (n=23) had a cardiac thrombus. Of 78 pts with available echocardiographic data at time of ICI initiation, the mean ejection fraction was 61+/- 7.1%. Cardiology referrals and cardiac MRIs since time of cancer diagnosis were completed on 53% (n=58) and 47% (n=52) of pts, respectively. Overall, 36.4% (n=40) of pts had cardiac complications from the mets, including arrhythmias (13%, n=14), arterial/venous emboli (3.6%, n=4), and cardiac tamponade (2.7%, n=3). For NSCLC, ORR, mPFS (95% CI), and mOS (95% CI) were 23%, 4.4 months (3.0-7.5), and 9.9 months (5.9-14.7), respectively. For melanoma, ORR, mPFS, and mOS were 35.7%, 9.1 months (5.2-20), and 29 months (14-58), respectively. Cardiac met ORRs for NSCLC and melanoma were 27% and 43%, respectively. 74% (N=71/96) of pts with evaluable response data had concordant response in the burden of overall disease and cardiac disease. IrAEs are shown. Conclusions: Although cardiac mets are frequently associated with cardiac complications, ICIs demonstrate meaningful efficacy with no overtly concerning safety signals. Close to three-quarter of pts have concordant response in the overall disease and cardiac disease burden. Multi-disciplinary approach involving cardiologists and oncologists need to be implemented to appropriately manage pts with cardiac mets. [Table: see text]

5 Background: Management options for patients (pts) with advanced (locally advanced or metastatic) PeCa are limited. The GSRGT assembled an international cohort of pts with advanced PeCa treated with ICI to evaluate toxicity and clinical outcomes. Methods: We retrospectively collected data on pts with advanced PeCa receiving ≥1 cycle of ICI between 2015-2022 at 18 medical centers in the US, Europe, and Asia. Immune-related adverse events (irAE) were graded per the Common Terminology Criteria for Adverse Events v5.0. Overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier method. Objective response rate (ORR) was determined by the clinical investigator per RECIST 1.1 criteria, whenever feasible. Results: Among 72 pts with advanced PeCa treated with ICI, 24 (33%) were Hispanic and 7 (10%) were Black. 60 (83%) pts had metastases while the remainder had locally advanced disease. The median age was 64 (inter-quartile range (IQR): 54,70) years and 48 (67%) had ECOG performance status ≥1. Most pts (n=60, 83%) were treated in the ≥2nd line setting and received pembrolizumab (n=23), nivolumab (n=15), cemiplimab (n=15), nivolumab and ipilimumab (n=7), or other anti-PD1/L1-based therapies (n=12). Among 37 pts with available data on HPV status, 24 (65%) were HPV+. 3 (4%) pts were HIV+. irAE of any grade occurred in 18 (25%) pts, 7 (10%) were grade ≥3, 7 (10%) required steroids, 6 (9%) required hospitalization, and 8 (11%) led to treatment discontinuation. The median OS and 24-month OS and median PFS and 24-month PFS were 9.4 (95%CI: 6.8, 12.8) months and 19.3% (95%CI: 9.2, 32.1) and 2.8 (95%CI: 2.1, 3.9) months and 11.2 % (95%CI: 4.9, 20.2), respectively. Among 66 pts evaluable for response, ORR was 7/66 (11%) (2 with complete response, 5 with partial response), and 16 (24%) pts had stable disease for a disease control rate of 35%. The median duration of response was 7.9 (IQR: 3, not reached) months. Conclusions: In the largest retrospective cohort of ICI-treated advanced PeCa, ICI showed no new safety signals, however, overall anti-tumor activity was limited. Future translational studies are needed to identify pts that are more likely to derive clinical benefit from ICI.