Real-world outcomes of lifileucel in advanced melanoma: A single-institution experience.

Abstract

9552 Background: Lifileucel (Amtagvi), an autologous tumor-infiltrating lymphocyte (TIL) therapy, was FDA approval for unresectable or metastatic melanoma after progression on systemic therapy based on clinical trial data. However, real-world data describing early outcomes with lifileucel remain limited. Methods: We retrospectively reviewed a prospectively maintained database of patients with unresectable/metastatic melanoma who progressed on immune checkpoint inhibitors (and BRAF ± MEK therapy if applicable) and received lifileucel per standard protocol at a single institution April 2024–January 2026. Eligible patients received an in-specification TIL product and had evaluable imaging ≥12 weeks post-infusion unless progression was detected sooner. Responses were assessed per RECIST v1.1. Endpoints included objective response rate (ORR), disease control rate (DCR), duration of response (DoR), progression-free survival (PFS), overall survival (OS), and grade ≥3 treatment-related adverse events (TRAEs), excluding lymphodepletion-related cytopenias. Time-to-event endpoints were estimated using Kaplan–Meier methods. Results: Of 38 patients who underwent surgical TIL harvest, 32 (84%) received lifileucel, including 5 via the Expanded Access Program due to out-of-specification product. Among 27 patients receiving in-specification lifileucel, 20 had evaluable imaging and were included in the analysis. Patients received a mean of 2.2 prior therapies, and 35% had acral lentiginous or mucosal melanoma. All patients had Stage IV disease, including liver (40%) and brain (30%) metastases. 55% received bridging therapy after surgery prior to infusion. Median follow-up was 5.7 months (range, 0.9–16.9). ORR was 30% (3 CR, 3 PR), and DCR was 45%. Among responders, 67% (4/6) have ongoing response and median DoR was not reached. Median PFS was 3.5 months (95% CI, 2.1–5.3) and median OS was 6.1 months, with 6- and 12-month OS rates of 51% and 44%, respectively. Non-cytopenic grade ≥3 TRAEs occurred in 55%. Conclusions: In this early real-world experience, lifileucel demonstrated encouraging antitumor activity with ongoing responses in heavily pretreated patients despite high-risk features such as elevated LDH and liver and brain metastases. Additional studies and longer follow-up are warranted to optimize patient selection and define durability of benefit and survival outcomes. Baseline patient characteristics and safety outcomes. Characteristic/Outcome Overall (N=20) Age, median (range), y 62 (38-80) Male sex, n (%) 12 (60) Acral lentiginous/mucosal subtype, n (%) 7 (35) BRAF V600E mutation, n (%) 4 (20) LDH level > ULN, No. (%) 5 (25) Liver Metastases, No (%) 8 (40) Brain Metastases, No (%) 6 (30) Prior systemic therapies, mean (range) 2.2 (1-5) Patients with grade ≥3 non-hematologic TRAEs, n (%) 11 (55)