StemRIM (TSE: 4599) told investors on September 9 that its licensed-out drug redasemtid, known internally as S-005151 and out-licensed to Shionogi & Co., produced two very different results in two very different diseases.
In a global late-stage Phase 2 trial of acute ischemic stroke, patients were dosed within 25 hours of symptom onset. In the cohort that did not receive endovascular reperfusion therapy, the trial's primary endpoint, the modified Rankin Scale score at 90 days, showed no statistically significant improvement for redasemtid over placebo. The trial missed its primary endpoint.
That is the headline number, and it is not good news for the stroke program. But the release also reports an exploratory subgroup finding: among patients with more severe stroke at onset, redasemtid showed a suggestive improvement in mRS scores, and a general improvement trend consistent with an earlier domestic Phase 2 trial was also observed. Both points are exploratory, not confirmatory, and StemRIM is careful to label the release itself a preliminary report rather than a full analysis.
| Trial | Population | Primary Endpoint | Result |
|---|---|---|---|
| Acute ischemic stroke (global late-stage Phase 2) | Patients dosed within 25 hours of onset; no-reperfusion cohort | Modified Rankin Scale score at 90 days vs. placebo | No statistically significant improvement; primary endpoint missed |
| Dystrophic epidermolysis bullosa (additional Phase 2) | Four patients | Closure of refractory ulcers | Achieved in 3 of 4 patients |
The second trial tells a different story. In an additional Phase 2 study of dystrophic epidermolysis bullosa, a severe genetic skin disorder in which minor friction causes blistering and erosion, four patients were treated, and three achieved closure of refractory ulcers, the trial's primary endpoint. Some patients also showed improvement in overall ulcerated skin area. Dystrophic epidermolysis bullosa accounts for roughly half of all epidermolysis bullosa cases, with an estimated 500 to 1,000 patients in Japan and no currently approved fundamental treatment.
On safety, StemRIM reports no new safety concerns and good tolerability in either trial, including comparable adverse-event rates between the redasemtid and placebo arms in the stroke study.
The decision on what happens next to the stroke program does not sit with StemRIM. Shionogi, which holds the license, will conduct a detailed analysis of the trial results and determine the future development policy for the acute stroke indication. StemRIM says it will support Shionogi's continued development in dystrophic epidermolysis bullosa, aiming to bring the drug to patients as quickly as possible. For a licensed-out asset, that split outcome puts the stroke program's fate in Shionogi's hands rather than StemRIM's.