This is an encouraging signal, but it does not yet prove that IMA402 extends patients’ lives. The data come from an ongoing Phase 1b study without a control group. Moreover, follow-up for overall survival was still relatively short, at a median of 8.8 months. The one-year rate is therefore an early estimate, rather than a comparison with an established therapy.
IMA402: As of the June 1, 2026, cutoff date, 126 patients with various advanced solid tumors had received at least one infusion of IMA402. They had previously received a median of three lines of systemic therapy. The efficacy analysis for the recommended Phase 2 dose range included 40 patients, 31 of whom had high PRAME expression, a cancer-associated protein that helps T cells identify tumors when targeted by treatment.
In this analysis group, IMA402 achieved a confirmed objective response rate of 25%: Tumors shrank measurably according to the study criteria in 10 of 40 patients. The disease control rate was 63%. In the subgroup with high PRAME expression, the confirmed response rate was 32%. Among the 22 melanoma patients in this group, seven responded to treatment. Median duration of response was 12.5 months; the longest ongoing remission had lasted more than two years.
The survival data also relate to the melanoma group with high PRAME expression. According to Immatics, 91% of patients were still alive after one year. For comparison, the company cites a one-year survival rate of 60% in patients treated below the recommended dose range. This difference is interesting, but it cannot readily be interpreted as a dose effect or an efficacy advantage: The dose groups were not compared in a randomized setting and may also differ in other characteristics. The small number of patients is a further limitation.
The response rate also needs to be put into context: 32% means that seven of 22 patients had a confirmed objective response — not that one-third of patients were cured. The duration of response provides an additional indication of potential clinical relevance, but it likewise cannot replace controlled evidence of efficacy.
A T-cell engager targeting a tumor antigen: IMA402 is part of Immatics’ TCER platform. The bispecific drug recognizes a peptide derived from the tumor antigen PRAME that is presented on the cell surface by the HLA molecule HLA-A*02:01, while simultaneously binding to CD3 on T cells. This is intended to enable the immune cells to recognize and attack tumor cells. Its use requires tumor cells to present the appropriate peptide-HLA complex; PRAME expression alone is not necessarily sufficient.
Immatics describes the tolerability profile as favorable. The most common treatment-related adverse events included transient lymphopenia and low-grade cytokine release syndrome. According to the company, no cases of immune effector cell-associated neurotoxicity syndrome (ICANS) and no treatment-related deaths were observed. However, the limited number of patients treated so far does not yet allow a definitive assessment of rare or late-onset risks.
Immatics plans to investigate IMA402 in additional solid tumors and in combination with immune checkpoint inhibitors. Initial data for a combination with the MAGEA4/8-targeted bispecific IMA401 in lung cancer are expected in 2027. The company is also relying on its own blood-based test to select patients with high PRAME expression.
PRAME-targeted cell therapy: Alongside IMA402, Immatics presented data for IMA203CD8, a personalized TCR T-cell therapy. In this approach, patients’ T cells are genetically modified to recognize PRAME-derived peptides and then reinfused. The therapy thus differs fundamentally from the bispecific antibody, which activates T cells already present in the body.
As of the Aug. 7, 2026, data cutoff, a total of 98 heavily pretreated patients had been enrolled in the ongoing Phase 1 study; 90 were evaluable for efficacy. Across all dose levels and tumor types studied, the confirmed response rate was 41%. This overall figure also includes lower doses that were not selected for further clinical development.
In a more narrowly defined group of 20 patients with gynecologic tumors who had received clinically relevant doses, the confirmed response rate was 55%. Median duration of response was 8.4 months. Median progression-free survival was 5.8 months; median overall survival had not yet been reached at a median follow-up of 7.8 months. Given the small, nonrandomized Phase 1 population, these results should also be viewed as early clinical signals at this stage.
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