ITIL-306

P1, N=1, Terminated, Instil Bio | N=51 --> 1 | Trial completion date: Nov 2039 --> Mar 2026 | Active, not recruiting --> Terminated; The study was terminated early due to discontinuation of development of the investigational program

P1, N=51, Active, not recruiting, Instil Bio | Phase classification: P1a/1b --> P1

P1a/1b, N=51, Active, not recruiting, Instil Bio | Recruiting --> Active, not recruiting

P1a/1b, N=51, Recruiting, Instil Bio | Not yet recruiting --> Recruiting

P1a/1b, N=51, Not yet recruiting, Instil Bio

When combined with TCR-specific binding, CoStAR significantly enhanced T-cell proliferation, persistence, and antitumor activity in vivo vs TCR alone, resulting in tumor control and prolonged survival. Effects were not observed with CoStAR alone, underscoring that signaling through CoStAR alone does not induce T-cell effector function. The sustained proliferation of anti-FOLR1 CoStAR T cells without exogenous IL-2 support in vitro and in vivo supports a clinical TIL regimen free of high-dose IL-2.

The novel anti-FOLR1 CoStAR molecule improves T-cell effector function through dual CD28- and CD40-mediated costimulation upon targeted engagement of tumor-expressed FOLR1. Anti-FOLR1 CoStAR TIL manufacturing is feasible in tumors associated with FOLR1 expression, including ovarian, lung, and renal. A first-in-human clinical study of ITIL-306, an anti-FOLR1 CoStAR TIL product, is planned.