HUTCHMED (NASDAQ:HCM) shares climbed 2.4% in premarket activity Friday after the firm unveiled positive Phase III findings for sovleplenib in warm antibody autoimmune hemolytic anemia during a presentation at the European Hematology Association (EHA) Congress.
The ESLIM-02 study achieved its primary endpoint, with sovleplenib producing a 66% durable response rate between weeks 5 and 24, compared with a 15% durable response rate for patients receiving placebo. The randomized, double-blind trial enrolled 90 patients in China who had relapsed or were refractory to at least one prior standard therapy for warm antibody autoimmune hemolytic anemia.
The data were presented Thursday at the EHA Congress in Stockholm, Sweden, and the presentation was selected for inclusion in the official EHA Press Program.
Beyond the primary endpoint, sovleplenib demonstrated a 70% overall response rate versus 22% for placebo in the trial population. The study also showed reductions in secondary measures of clinical burden: 16% of patients in the sovleplenib arm required rescue therapy compared with 54% of placebo patients, and red blood cell transfusions were needed in 11% of the sovleplenib group versus 43% among those on placebo.
Onset of response was faster with sovleplenib, with a median time to response of 3.1 weeks versus 6.3 weeks for placebo. For those who achieved an overall response, the median cumulative duration of response was 16.1 weeks with sovleplenib compared with 6.1 weeks for placebo.
Regulatory progress in China has been noted alongside the clinical results. A New Drug Application for sovleplenib intended for adults with warm antibody autoimmune hemolytic anemia who showed an insufficient response to at least one prior glucocorticoid treatment was accepted for review and granted priority review by the China National Medical Products Administration in April. The NMPA previously awarded sovleplenib Breakthrough Therapy Designation in March.
Safety data from ESLIM-02 showed that grade 3 or higher treatment-emergent adverse events occurred in 43% of patients receiving sovleplenib and in 59% of patients in the placebo arm. No treatment-related deaths or treatment discontinuations were reported in the sovleplenib group.
What this means
The ESLIM-02 results provide evidence that sovleplenib produced higher durable and overall response rates than placebo in the study population, while also reducing the need for rescue therapies and transfusions. The NMPA's acceptance and priority review of an NDA, together with the Breakthrough Therapy Designation, establish a parallel regulatory pathway in China while the company advances its clinical position.