Immatics has vaulted into phase 3 on the strength of early-stage data. The biotech is gearing up to start a pivotal trial of its melanoma cell therapy IMA203 this year in light of the response and progression-free survival (PFS) results seen in a phase 1b study.
Transatlantic biotech Immatics sketched out plans to run a phase 2/3 trial of IMA203 in second-line and later melanoma earlier this year. Management confirmed the plan Thursday, when executives shared updated phase 1b data alongside a closer look at the next steps for the TCR-T cell candidate. IMA203 is designed to bind to PRAME, a receptor found in most melanomas, and trigger tumor killing.
Immatics ran a phase 1b trial to provide preliminary evidence of efficacy. The biotech reported median PFS of 6 months in the study, up from 2.6 months in an earlier phase 1a dose-escalation trial. Immatics has picked PFS as the primary endpoint in the phase 3 trial.
The pivotal study will randomize people with unresectable or metastatic melanoma who have received a checkpoint inhibitor in the past to take IMA203 or investigator’s choice of selected approved treatments. Immatics said the expected PFS in the population is two to three months.
Iovance Biotherapeutics’ autologous T-cell therapy Amtagvi achieved a median PFS of 4.1 months. Drug combinations based on Bristol Myers Squibb’s Opdivo and Yervoy have chalked up PFS of two to three months.
Immatics said a PFS primary endpoint is the fastest pathway to full approval and “presents a more attractive commercial positioning” than response rate. Linking the candidate to improved overall survival could put Immatics in a stronger still commercial position, but the biotech has backed away from that challenge. A secondary endpoint of the trial will target “no overall survival detriment.”
The biotech is aiming to file for full approval in early 2027. That target assumes the study starts late this year and completes enrollment in 2026. A prespecified interim data analysis is planned for early 2026.
Immatics ended June with enough cash to fund operations into 2027. The biotech moved to top up its bank balance on Thursday, proposing a $150 million public offering. Immatics’ press release about the offering lacks a prediction of how the financing will affect its cash runway.