Evaluation of autologous tumor-infiltrating lymphocytes (GT201) plus toripalimab in recurrent or metastatic head and neck cancer.

Abstract

6049 Background: Immune checkpoint inhibitors (ICIs) are the standard treatment for recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (HNC) after failure of platinum-based chemotherapy; however, the clinical benefit remains limited, with reported overall response rate (ORR) of approximately 13% and median progression-free survival (PFS) of about 2 months in the second line setting. GT201 is an autologous TIL therapy engineered to express membrane-bound IL-15 (mbIL-15), which may enhance immune activation in the tumor microenvironment and promote durable response. We report preliminary safety and efficacy results from an open-label, single-arm study evaluating GT201 in combination with the PD-1 inhibitor toripalimab in patients with R/M HNC (NCT06190275). Methods: The primary endpoint was safety, including treatment-emergent adverse events (TEAEs) graded per CTCAE v5.0. Secondary endpoints included ORR, disease control rate (DCR), PFS, duration of response (DOR), and overall survival (OS), assessed per RECIST v1.1. Results: As of November 30, 2025, 6 patients with R/M HNC were treated (median age of 57 years; median 1 prior line of therapy). Histology indicated 5 squamous cell carcinoma and 1 lymphoepithelial carcinoma. All patients received 1–2 cycles of bridge therapy, followed by lymphodepletion (low-dose in 5 patients; intermediated-dose in 1 patient), GT201 infusion (5×10 9 -5×10 10 viable cells), and high-dose IL-2 (600,000 IU/Kg; 4-6 doses). Five patients subsequently received toripalimab; one patient progressed prior to PD-1 inhibitor treatment. Maximum follow-up was 15.5 months. Most of AEs were Grade 1-2. Grade ≥ 3 AEs were primarily related to lymphodepletion and IL-2, and included cytopenia, neutropenia, lymphocytopenia, monocytopenia, hypokalemia, rash, and increased bilirubin; all resolved or improved to Grade ≤ 2 within 14 days. The ORR was 66.7% (4/6), including 2 complete response (CR) and 2 partial response(PR); DCR was 83.3% (5/6). One patient with CR remains progress-free exceeding 12 months. Median PFS and OS have not yet been reached. GT201 cells expanded robustly and persisted in peripheral blood for at least 6 months post-infusion. Conclusions: GT201 combined with toripalimab demonstrated a manageable safety profile and encouraging antitumor activity in heavily pretreated R/M HNC, supporting further clinical development of this combination. Clinical trial information: NCT06190275 . Research Sponsor: Grit Biotechnology.