Does Invika Treat Immunotherapy-Resistant Tumors? What 4 Responses in 27 Mean

Short answer: In a first-in-human phase 1 and early phase 2 trial, four of 27 people (14.8%) treated at the selected biological doses of invikafusp alfa, or invika, had confirmed tumor shrinkage of more than 30%. Disease had not progressed at the assessment point in 16 of 27 (59.3%). These are preliminary, uncontrolled results in heavily treated advanced solid tumors. Invika is investigational, and the study does not yet establish longer survival or durable benefit.

What kind of treatment is invika?

Invikafusp alfa is a first-in-class bispecific antibody designed to stimulate T cells carrying two T-cell receptor families, Vβ6 and Vβ10. Instead of broadly activating the immune system, it aims to expand a restricted group of tumor-infiltrating T cells.

The trial found dose-dependent expansion of those target T-cell populations in blood and tumors, with little effect on other T cells. The four tumor responses occurred among participants with the largest target-cell shifts. But immune activation did not consistently translate into measurable tumor benefit, an important distinction in an early mechanistic study.

How should the 59.3% and 14.8% figures be read?

Among 27 participants who received the two optimal biological doses, 16 had no progression at the reported assessment point. That disease-control group can include people whose tumors shrank and people whose disease remained stable.

The objective response rate was narrower: four of 27 participants, or 14.8%, had confirmed partial responses, meaning targeted tumors decreased by more than 30%. Responders included people with microsatellite-stable metastatic colorectal cancer and PD-L1-negative non-small cell lung cancer, tumor settings that can be difficult to treat with standard checkpoint immunotherapy. NIH reported that two colorectal cancer responders received invika as seventh-line therapy.

“No progression” is therefore not interchangeable with “tumor shrinkage,” remission or cure. The 59.3% figure should not be presented as a response rate. The data also do not yet show how invika compares with another therapy or how much it changes progression-free or overall survival.

What did phase 1 and early phase 2 do?

Phase 1 enrolled 34 participants across six doses, from 0.01 to 0.16 mg/kg every two weeks. Its central jobs were to characterize safety, pharmacology and dose-related immune activity. A maximum tolerated dose was not reached. Integrated safety, drug exposure and biological-effect data led investigators to select 0.08 mg/kg as the recommended phase 2 dose.

The initial phase 2 analysis included 18 participants. The headline 27-person group combines participants from both phases who received 0.08 or 0.12 mg/kg, the doses described as optimal biologically. This is why the efficacy subgroup does not equal the full trial enrollment in either phase. The paper’s data cutoff was March 12, 2025, and phase 2 evaluation is continuing.

What is known about safety?

Cytokine release syndrome was the most common treatment-related adverse event and was mainly grade 1 or 2. Two participants experienced reversible dose-limiting toxicities at different dose levels. The reported analysis recorded no treatment-related deaths and no non-laboratory grade 4 treatment-related adverse events.

That is not the same as proving the drug safe. Small early trials are not designed to define rare harms, long-term toxicity or safety across a broad cancer population. Cytokine release syndrome can require monitoring and treatment even when most episodes in one study are lower grade.

Does FDA Fast Track mean invika is approved?

No. FDA has granted Fast Track designation to invika’s development for tumor-mutation-burden-high metastatic colorectal cancer and, more recently, selected TMB-high solid tumors after prior therapy including checkpoint inhibition. Fast Track can increase communication with FDA and support an expedited development path for a serious condition.

It is not marketing authorization and does not establish effectiveness. As reviewed on October 25, 2026, invika remains an experimental therapy being studied in clinical trials. Eligibility for START-001 depends on tumor type and biomarkers, prior treatment, organ function, performance status and other protocol criteria.

Who do these results apply to?

The participants had unresectable, locally advanced or metastatic solid tumors for which curative standard therapy was ineffective or unavailable. Many had received multiple previous treatments, and most tumors had responded poorly to immune checkpoint blockade.

The analysis mixes several tumor types. Four responses are too few to estimate reliable response rates for colorectal, lung or any other individual cancer. The findings also should not be assigned to earlier-stage disease, operable tumors, or people who have not received checkpoint therapy.

Important limitations

• No control group: the trial cannot show whether participants lived longer or fared better than comparable patients receiving another treatment.
• Small efficacy subgroup: four responses among 27 people provide a signal, not a stable tumor-specific estimate.
• Early-phase design: phase 1 primarily tested safety and dose selection; the phase 2 findings remain initial.
• Disease control is not response: stable disease contributed to the 16 people without progression, while only four met objective-response criteria.
• Long-term outcomes are immature: duration of response, progression-free survival and overall survival require more follow-up.
• Sponsor involvement: the developer, Marengo Therapeutics, sponsored the study; participant-level data sharing is planned after trial completion and review of qualified requests.

The useful conclusion

START-001 provides early human evidence that selective stimulation of Vβ6/Vβ10 T cells can generate tumor activity in some cancers that resisted checkpoint immunotherapy. The four responses justify further testing; they do not establish a new standard of care. Larger phase 2 cohorts, cancer-specific analyses, response durability and stronger comparative evidence will determine whether invika has a clinically useful role.

---

Primary sources

• U.S. NIH/NCI: A precision T-cell therapy stalls treatment-resistant cancers in clinical trial (October 23, 2026)
• Sullivan et al.: Bispecific dual T cell agonist invikafusp alfa in solid tumors—the START-001 trial (Nature Medicine, October 23, 2026)
• ClinicalTrials.gov: START-001, NCT05592626

Prepared by: Life Choice Note, an independent personal health-information explainer · Reviewed: October 25, 2026

This article provides general information, not individual cancer-treatment or clinical-trial instructions. Treatment and trial eligibility require review by an oncology team and the study site.