A phase 3 trial of Hutchmed’s autoimmune disease candidate sovleplenib has hit its primary endpoint, delivering a boost to an asset that was held up by quality issues in another indication.
Hong Kong-based Hutchmed is developing its Syk inhibitor in immune thrombocytopenia (ITP) and warm antibody autoimmune hemolytic anemia (wAIHA). The breach of an impurity limit delayed an attempt to win approval in ITP in China, forcing the biotech to perform chemistry, manufacturing and controls work in preparation for resubmission in the first half of 2026.
Hutchmed has continued to test sovleplenib in wAIHA in parallel, culminating in the delivery of data from a Chinese phase 3 trial that could lead to approval of the asset in the autoimmune disease. The wAIHA study met its primary endpoint of durable hemoglobin response rate within Weeks 5 to 24 of treatment.
The biotech is yet to share its pivotal data. In the phase 2 part of the trial, Hutchmed reported an overall response rate of 43.8% in the sovleplenib cohort in the first eight weeks, compared to 0% on placebo. The overall response rate across 24 weeks of daily oral treatment with sovleplenib was 66.7%.
People with wAIHA currently receive supportive therapy that can include corticosteroids and rituximab. Rigel Pharmaceuticals studied a rival Syk inhibitor, which is approved in ITP, in wAIHA but dropped plans to seek approval in the indication after failing a phase 3 trial. Sanofi, with its BTK inhibitor Wayrilz, and Johnson & Johnson, with its anti-FcRn antibody Imaavy, have late-phase programs in wAIHA.
Hutchmed plans to file for approval of sovleplenib in wAIHA in China in the first half of 2026. The biotech pulled back from global sovleplenib development after encountering the quality issue during its filing for approval in ITP in the country.
Executives have discussed partnering the Syk program globally. On an earnings call in August, Hutchmed CEO Weiguo Su, Ph.D., said the company could advance a new chemical entity with full patent life in the U.S. Switching to the new Syk molecule could support “a very short development timeline” for an asset with a longer period of exclusivity, making it “a very attractive outlicensing opportunity,” the CEO said.