Immatics' IMA203CD8 Achieves 51% ORR Across Solid Tumors and 60% in Gynecologic Cancers
IMTX is trading near its 52-week low of $6.65 (11% above the low).
Summary
Immatics released full Phase 1 data for IMA203CD8 showing a 51% objective response rate across 90 evaluable patients and 60% in gynecologic cancers at higher doses, with a manageable safety profile and the maximum tolerated dose not reached.
Key Events · Product Development and Regulatory · IMTX
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IMA203CD8 Phase 1 Data Released
Among 90 efficacy-evaluable patients with advanced PRAME-positive solid tumors, ORR was 51% (46/90) and confirmed ORR 41% (36/87); disease control at week 6 was 82% (74/90), and 83% (71/86) had tumor reduction.
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Gynecologic Cohort Shows 60% ORR
In 20 gynecologic cancer patients treated at clinically relevant doses (>=DL4c), ORR was 60% (12/20) and cORR 55% (11/20), with median duration of response 8.4 months and median PFS 5.8 months at 8.1 months follow-up.
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Safety Manageable, MTD Not Reached
Cytokine release syndrome was mostly grade 1-2, ICANS was infrequent, dose-limiting toxicities occurred in 4 of 98 patients, no IMA203CD8-related grade 5 events occurred, and the maximum tolerated dose was not reached up to 12.5 billion cells.
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Next Steps: Uterine Expansion, Pediatric IIT
Phase 1a dose escalation is complete; Immatics is enrolling uterine cancer patients at clinically relevant doses and plans a Phase 1/2 investigator-initiated trial in PRAME-positive pediatric cancers to start in 1H 2027.
Analysis · IMTX · Life Sciences
The first full Phase 1 dataset for IMA203CD8, the CD8-armored version of Immatics' PRAME TCR-T program, shows competitive activity in a heavily pretreated population (median 3 prior lines). Among 90 evaluable patients, the objective response rate was 51% and confirmed ORR 41%, with tumor shrinkage in 83% and some responses still ongoing beyond 2.5 years. The commercially relevant slice is gynecologic cancer at clinically relevant doses: 60% ORR and 55% cORR in 20 patients, with a median duration of response of 8.4 months and median PFS of 5.8 months. Safety looks manageable—cytokine release syndrome was mostly grade 1-2, neurotoxicity was infrequent, no drug-related grade 5 events occurred, and the maximum tolerated dose was not reached up to 12.5 billion cells. That supports pushing into targeted cohorts (ovarian, uterine, rare and pediatric cancers) rather than a broad tumor-agnostic launch. With $150 million raised in August and cash runway into 2028, this is a data readout that shapes the registration path, not a financing event.
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At the time of this filing, IMTX was trading at $7.36 on NASDAQ in the Life Sciences sector, with a market capitalization of approximately $1.1B. The 52-week trading range was $6.65 to $12.41. This filing was assessed with positive market sentiment and an importance score of 7 out of 10.