MDNA11 Posts 40% Response Rate in Checkpoint-Resistant Gut Cancers at SITC 2026

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Medicenna Therapeutics announced new results from its Phase 1/2 ABILITY-1 study on Monday, showing its experimental IL-2 Superkine MDNA11 shrank tumours in 40 percent of patients with biomarker-enriched gastrointestinal cancers whose disease had already resisted approved therapies. The data were presented in an oral session at the Society for Immunotherapy of Cancer's 2026 annual meeting in Phoenix by Prof. Paolo Ascierto of the National Cancer Institute in Naples.

Among 20 patients whose tumours could be assessed, eight responded and 16 had their disease controlled, giving a disease control rate of 80 percent. Responses appeared across colorectal cancer, pancreatic cancer, bile duct cancer and anal cancer, and in five of the eight responders the response was confirmed. The median duration of response had not been reached, with responses still ongoing. Patients in the group were heavily pretreated, with a median of three earlier lines of therapy, and nearly two-thirds had already received checkpoint immunotherapy.

The sharpest signal came from patients with liver metastases, a group that usually responds poorly to checkpoint drugs. All four patients with measurable liver tumours who received MDNA11 alone saw those tumours shrink, and all eight liver lesions measured across the group regressed. The study also reported durable activity in advanced cutaneous melanoma that had resisted checkpoint therapy, including a 30 percent response rate with MDNA11 alone in patients whose cancer had returned after an initial response to immunotherapy. A separate endometrial cancer group saw a confirmed response rate of 28.6 percent with the combination.

The numbers come from Medicenna's own release of the SITC presentation, and the response counts line up between the release's summary and its detailed breakdowns. Four of 11 patients responded on monotherapy and four of nine on the combination, adding to eight of 20 overall. The liver finding is reported the same way in both places, four patients and eight lesions, and the melanoma figures match the expansion-cohort counts given in the release. The trial is registered as NCT05086692, and the presentation was listed as abstract 517 among the meeting's top 150 abstracts, a detail Medicenna had announced in October. What the release does not yet show is how long the responses last beyond the point where the median duration had not been reached, and the gastrointestinal group is small, so the figures describe an early signal rather than a settled result.

For patients whose gastrointestinal cancers carry the MSI-H or high tumour-mutational-burden markers and have already failed checkpoint therapy, there are few treatments left, and the release notes that published salvage options have produced response rates in the low teens. A 40 percent response rate in that setting, if it holds in larger groups, would give oncologists a new option where the standard approaches have run out. Medicenna's chief executive said the company is positioning MDNA11 for potential registrational studies, and more data from the melanoma and endometrial groups is due at a webinar on November 10.