Korolewicz, James

Background Data on the safety profiles and clinical outcomes of patients with solid tumors and cardiac metastasis treated with immune checkpoint inhibitors (ICIs) are limited. Methods This is an international multicenter retrospective study of patients with cancer and cardiac metastasis at baseline. Patients who had received ≥1 dose of ICI were included. Treatment-related adverse events (trAEs) were graded per Common Terminology Criteria for Adverse Event V.5.0. Objective response rates (ORR) were evaluated by Response Evaluation Criteria in Solid Tumors V.1.1 when available. Overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier method. Results Among 110 pts, median age at ICI initiation was 65 (IQR: 59–75). Median follow-up time since ICI initiation was 36 (95% CI: 26 to 51) months. Melanoma (38%, n=42) and non-small cell lung cancer (24%, n=26) were the most common. 68 (62%) patients received ICIs as first-line, and 29 (26%) patients were treated with combination anti-programmed death-1 and anti-cytotoxic T-lymphocyte antigen 4. The most common location of cardiac metastasis was in the atria (37%, n=41) and ventricles (35%, n=39). 15 patients (13.6%) had bilateral cardiac/pericardial metastasis, 44 (40%) had left-sided, and 43 (39.8%) had right-sided. At ICI initiation, 21% (n=23) had a cardiac thrombus. Cardiology referrals and cardiac MRIs at the time of cancer diagnosis were completed on 58 (53%) and 52 (47%) patients, respectively. Cardiac events occurred in 40 (36%) patients, including arrhythmias (n=14, 13%), arterial/venous emboli (n=4, 3.6%), and cardiac tamponade (n=3, 2.7%). 53 (47%) patients developed trAEs; most common were colitis/diarrhea (n=16, 15%), dermatitis (n=13, 12%), and hepatitis (n=9, 8.2%). ICI-related major cardiac trAEs occurred in 2 (1.8%) patients. 22 patients (20%) developed grade ≥3 trAE. Patients with multiple cardiac metastases had significantly lower responses to ICI-based regimens compared with patients with single cardiac metastasis (11% vs 63%, p=0.02). For melanoma, ORR, median PFS, and median OS were 38%, 9.0 months, and 28.9 months, respectively. 83% of patients with melanoma had concordant responses in overall disease burden and cardiac disease. 91 patients discontinued ICIs, and the main reason was progression or death in 55 (49%) patients. Conclusions Among patients with pre-existing cardiac metastasis, ICIs demonstrated meaningful clinical efficacy with no increase in safety signals. Most patients had concordant responses in the overall disease burden and cardiac mass. Multidisciplinary teams are crucial for the appropriate management of patients with cardiac metastasis.

4580 Background: ICIs are used for UC in different settings. Most cases have pure urothelial carcinoma (PUC) but about a third have UC mixed with SH. We examined pts with UC treated with ICI and hypothesized that outcomes would not differ between PUC and mixed with SH. Methods: We retrospectively included pts with PUC and any SH component treated with ICI as adjuvant, 1st line [1L] upfront, maintenance avelumab [mAV], ≥2nd line [2+L] therapy; pts were divided by SH type. Pts with multiple SH were included as separate group. We excluded pts with pure non-UC histology and pts treated with neoadjuvant ICI. We calculated overall response rate (ORR), median overall, progression-free and disease-free survival [mOS, mPFS, mDFS] using KM method from ICI start. Analysis was stratified by therapy line; multivariable models were adjusted by Khaki factors for 1L/upfront, mAV and Bellmunt factors for 2+L; reference group was PUC. We used descriptive statistics for small subsets. Results: We included 1525 pts from 26 sites; n=752 1L, n=609 2+L; 76% men, 80% White, 69% smoking history, 80% lower urinary tract primary, 28% SH. Median f/u time from 1L ICI start 24 months (mo): mPFS was 3 (95%CI 2.8-3.2) mo for PUC (n=340), 3 (95%CI 2-4) mo for squamous (n=60) (HR=1, [95%CI 0.7-1.4]), 2 (95%CI 1.4-3.2) mo for micropapillary (n=36) (HR=1.3 [95% 0.9-2]) and 4 (3.5-4.5) mo for ≥2 SH (n=20) (HR=0.9 [95%CI 0.6-1.5]). Median f/u time from 2+L ICI start 26 mo: mPFS was 3 (95%CI 2.4-3.2) mo for PUC (n=264), 4 (95%CI 2-5) mo for squamous (n=33) (HR=0.8, [95%CI 0.6-1.2]), 3 (95%CI 1.6-3.7) mo for micropapillary (n=17) (HR=0.9 [95% 0.6-1.7]) and 3 (2.5-3.1) mo for ≥2 SH (n=10) (HR=1.2 [95%CI 0.6-2.2]); Table shows ORR/OS data. Data on adjuvant and mAV settings will also be presented. Conclusions: We found no significant survival difference between PUC and SH. ORR was numerically higher with sarcomatoid SH and ≥2 SH in the 1L upfront setting. Limitations: retrospective design, small sample size in a few subsets, lack of randomization and central scan/path (% SH) review, selection bias, unmeasured confounders. [Table: see text]