What happened

Shares of Immatics NV (IMTX -0.96%) were soaring 17.5% as of 11:03 a.m. ET on Tuesday and jumped as much as 36.3% earlier in the day. The big gain came after the biopharmaceutical company announced interim data from one patient cohort of an ongoing phase 1b study evaluating IMA203 in treating solid cancers. IMA203 is an experimental T cell receptor-engineered T cell (TCR-T) therapy.

So what

Investors were especially pleased with the interim efficacy data for IMA203. An initial objective response rate (the percentage of patients experiencing tumor shrinkage) in the phase 1b study was 64% at week six. At three months, the objective response rate was 67%.

The responses appeared to be durable as well. Immatics said that there were two confirmed partial responses ongoing after more than nine months of treatment. Three other partial responses were ongoing at the time of the data cutoff.

IMA203's safety profile also seemed to be relatively good. Immatics stated that the therapy "continues to show manageable tolerability." The trial revealed no high-grade cytokine release syndrome (CRS) and no immune effector cell associated neurotoxicity syndrome (ICANS), two side effects common with similar immunotherapies.

It's important to keep in mind, however, that these were early results. The cohort for which Immatics reported data included only 11 patients.

Now what

The biotech stock has also benefited from other good news recently. Immatics announced on Monday that Bristol Myers Squibb exercised an option on licensing one of the four TCR-T candidates that are part of the two companies' collaboration. This move helps bolster Immatics' already substantial cash position. The small drugmaker shouldn't have to raise additional capital anytime soon.

As for IMA203, Immatics plans to provide another data update in the fourth quarter of this year. The company also hopes to clarify its path for clinical studies needed to pursue regulatory approvals for the immunotherapy at that time.