Immune-related adverse events to predict outcomes in recurrent/metastatic cervical cancer treated with cemiplimab: Insights from a rescue access program in Poland.

e17504 Background: Recurrent/metastatic cervical cancer remains a significant clinical challenge, particularly after progression on platinum-based chemotherapy. Cemiplimab, a programmed death-1 (PD-1) inhibitor, has shown survival benefits in this population, but real-world data exploring the relationship between immune-related adverse events (irAEs) and outcomes are limited. Methods: This ambispective study analyzed patients with recurrent/metastatic cervical cancer treated with cemiplimab under a rescue access program across five reference centers in Poland. Eligible patients received at least one cycle of cemiplimab between Oct 2022 and Jan 2025. Treatment outcomes, including overall survival (OS), progression-free survival (PFS), and objective response rate (ORR), were evaluated. The incidence and severity of irAEs assessed safety, graded according to Common Terminology Criteria for Adverse Events v5.0. The relationship between irAEs and clinical outcomes was analyzed using Kaplan-Meier survival analysis and multivariate Cox proportional hazards models with p<0.05 considered statistically significant. Results: Among the 37 patients, the median age was 58 years (interquartile ranges [IQR]: 42.5-65.8). After a median follow-up of 10.2 months (IQR: 7.6-12.8), the median PFS was 5.7 months (95% confidence interval [CI]: 4.9–6.4), while the median OS was 12.3 months (95%CI: 8.1-6.5). The ORR was achieved in 21.6% (n=8), with stable disease observed in 40.5% (n=15) and progressive disease (PD) in 37.8% (n=14). IrAEs occurred in 45.9% of patients (n=17). Patients who experienced irAEs had a significantly longer median PFS compared to those without irAEs (not reached vs. 3.3 months, log-rank p=0.001). The occurrence of irAEs was associated with an 80% lower risk of disease progression (hazard ratio [HR] 0.2, 95% CI: 0.1–0.6, p=0.002); however, irAEs had no significant impact on OS. The most frequent irAEs were thyroid dysfunction (n=11, 64.7%) and hepatotoxicity (n=3, 17.6%). Most irAEs were mild (grade [G] 1), while moderate toxicities (G2) were reported in 3 cases (17.6%), including hepatotoxicity, musculoskeletal symptoms, and hypothyroidism. Severe toxicities (G3) occurred in 2 cases (11.8%), comprising hepatotoxicity and skin rash. The median time to irAEs onset was 2 months. Steroid treatment was required in 3 cases, with a median dose equivalent to 1 mg/kg of prednisone. Treatment was discontinued due to toxicity in 2 patients (5.4%), while 24 patients (64.9%) stopped treatment due to PD, and 11 patients (29.7%) continued therapy. Conclusions: Our findings highlight the association between irAEs and improved outcomes in patients with recurrent/metastatic cervical cancer treated with cemiplimab. This underscores the importance of early detection and managing irAEs to optimize treatment efficacy.