A phase 1 study of fianlimab (anti-LAG-3) in combination with cemiplimab (anti-PD-1) in patients with advanced ccRCC.
Authors: Miso Kim, Raymond S. McDermott, Stephen K. Williamson, Byoung Chul Cho, Afshin Dowlati, Nehal J. Lakhani, Jyoti Malhotra, John M. Kaczmar, Kyriakos P. Papadopoulos, Howard Safran, Raid Aljumaily, Jayakumar Mani, Fang Fang, Shuquan Chen, Mark Salvati, Israel Lowy, Matthew G. Fury, Karl Lewis
Journal: Journal of Clinical Oncology (2024)

434 Background: Concurrent blockade of lymphocyte-activation gene 3 (LAG-3) may enhance efficacy of anti–programmed cell death protein 1 (PD-1) therapies. We present safety and clinical activity data from a Phase 1 study in patients with clear cell renal cell carcinoma (ccRCC) treated with anti–LAG-3 (fianlimab) + anti–PD-1 (cemiplimab). Methods: Patients with advanced or metastatic ccRCC who had received no more than 2 previous regimens of anti-angiogenic therapy who were anti–PD-1/PD-L1-naïve (cohort 3) or anti–PD-1/L1-experienced with most recent dose within 3 months prior to screening (cohort 4) were eligible. All patients were to receive fianlimab 1600 mg + cemiplimab 350 mg intravenously every 3 weeks for up to 24 months. Tumor measurements were performed by RECIST 1.1 every 6 weeks for 24 weeks, then every 9 weeks. Results: 15 patients (median age: 64 years) each in cohort 3 and 4 (total N=30) were enrolled and treated with fianlimab + cemiplimab as of 01 Nov 2022 data cutoff.For cohorts 3 and 4 respectively, 80% and 87% of patients were male, and 40% and 87% were White. All patients had prior cancer-related systemic therapy. 60% (9/15) and 93% (14/15) of patients in cohorts 3 and 4 had ≥2 lines of prior therapies, respectively. For cohorts 3 and 4, median treatment duration was 27 weeks and 18 weeks, and median follow-up was 13 months and 24 months, respectively. Grade ≥3 treatment-emergent adverse events (TEAEs) occurred in 53% and 33% of patients in cohorts 3 and 4, respectively. Serious TEAEs occurred in 33% and 13% of patients in cohorts 3 and 4, respectively. Treatment-related TEAEs (TRAEs) were reported in 80% of patients in cohorts 3 and 60% of patients in cohort 4. The most common TRAEs (any grade) were rash (27%) and infusion related reaction (grade 1 and 2) (27%) in cohort 3 and fatigue (20%) in cohort 4. Grade ≥3 TRAEs occurred in 27% of patients in cohorts 3. Treatment was discontinued due to any TEAE in 3 patients in cohort 3 and 1 patient in cohort 4. In cohort 3, there was one death. The patient was a 79-year-old woman with a history of antiphospholipid syndrome who died from complications of biopsy-proven ischemic colitis attributed to study treatment. RECIST 1.1-based investigator-assessed objective response rate (ORR) was 20% (3 partial responses [PRs]) in cohort 3 and 7% (1 PR) in cohort 4. The disease control rate (DCR) was 60% and 73% in cohorts 3 and 4, respectively. Kaplan–Meier estimation of median progression-free survival was 4 months (95% confidence interval [CI], 1–10) in cohort 3 and 4 months (95% CI, 1–7) in cohort 4 patients. Duration of responses were 4, 7, and 26 months in 3 responders in cohort 3; and 6 months in one responder in cohort 4. Conclusions: Fianlimab + cemiplimab demonstrated promising signs of clinical activity with durable responses among patients with anti–PD-1/PD-L1-naïve (cohort 3) and anti–PD-1/L1-experienced (cohort 4), with an acceptable safety profile. Clinical trial information: NCT03005782 .