Efficacy and safety of lifileucel, an autologous tumor-infiltrating lymphocyte cell therapy, and pembrolizumab in patients with immune checkpoint inhibitor-naive unresectable or metastatic melanoma: Updated results from IOV-COM-202 cohort 1A.

9505 Background: Immune checkpoint inhibitors (ICI) are front-line standard-of-care treatment (tx) for advanced (unresectable or metastatic) melanoma. Despite recent advances in front-line tx, a majority of patients (pts) do not achieve long-term benefit. Lifileucel, a one-time autologous tumor-infiltrating lymphocyte (TIL) cell therapy, potentially induces durable responses in pts with advanced melanoma previously treated with ICI. This study evaluates lifileucel combined with anti-PD-1 therapy in front-line advanced melanoma. Methods: IOV-COM-202 (NCT03645928) Cohort 1A assesses the efficacy and safety of lifileucel and pembrolizumab (pembro) in pts with ICI-naive unresectable or metastatic melanoma. Pts may have received BRAF/MEK inhibitor tx if BRAF mutation-positive. Eligible pts must have ≥1 resectable lesion (≥1.5 cm diameter) for 22-day cryopreserved lifileucel manufacturing, and ≥1 measurable lesion for response assessment per RECIST v1.1. The tx regimen consists of pembro, nonmyeloablative lymphodepletion (cyclophosphamide and fludarabine), a single lifileucel infusion (1 × 10 9 – 150 × 10 9 cells), ≤6 doses of IL-2 (600,000 IU/kg IV), and continued pembro until disease progression, or unacceptable toxicity for ≤24 months. The endpoints are investigator-assessed objective response rate (ORR) and incidence of grade ≥3 treatment-emergent adverse events (TEAE). Results: As of 22-Dec-2023, 22 pts with a median (range) age of 48.5 (18–68) years received lifileucel and pembro. At baseline, the median (range) target lesion sum of diameters was 54.5 (14–355) mm; 7 (31.8%) pts had liver lesions. Metastatic staging at study entry was as follows: 4 (18.2%) had M1a, 2 (9.1%) had M1b, 10 (45.5%) had M1c, and 2 (9.1%) had M1d. Eight (36.4%) pts had V600 BRAF mutations; 3 (13.6%) pts had prior BRAF/MEK inhibitor tx. Confirmed ORR was 63.6% (14/22), including 22.7% (5/22) CR and 40.9% (9/22) PR; 6 pts (27.3%) had SD. Median time to initial response was 2.5 months. All response evaluable pts demonstrated regression of target lesions. At a median follow-up of 17.2 months, median duration of response was not reached. Responses deepened over time; 10/14 (71.4%) pts had ongoing response and 8/14 (36.4%) pts had response ≥12 months. TEAEs were consistent with the underlying disease and known safety profiles of pembro, nonmyeloablative lymphodepletion, and IL-2. Most common grade ≥3 TEAEs were thrombocytopenia (68.2%), neutropenia (50.0%), and anemia (45.5%). Conclusions: These results demonstrate encouraging efficacy and durability for the combination of lifileucel and pembro and support its further evaluation in pts with untreated advanced melanoma in the phase 3 study TILVANCE-301 (NCT05727904). Clinical trial information: NCT03645928 .