— Publication shows treatment demonstrated durable response rate of 48.4% vs. 0% with placebo —

— Presentations at EHA showcased subgroup analyses demonstrating consistent benefits regardless of prior lines of therapies or prior TPO/TPO-RA1 exposure —

— Data supported regulatory submission in China accepted in January 2024 —

HONG KONG and SHANGHAI and FLORHAM PARK, N.J., June  17, 2024  (GLOBE NEWSWIRE) -- HUTCHMED (China) Limited ("HUTCHMED") (Nasdaq/AIM:HCM; HKEX:13) today announces that results from ESLIM-01, HUTCHMED's Phase III trial of sovleplenib (HMPL-523), in adult patients with primary immune thrombocytopenia ("ITP") in China, were published in The Lancet Haematology. Additional details and subgroup results of the study were also presented on June 14 at the European Hematology Association ("EHA") 2024 Hybrid Congress as an oral and two poster presentations.

Sovleplenib is a novel, selective, oral inhibitor targeting spleen tyrosine kinase ("Syk") for the treatment of hematological malignancies and immune diseases. Syk is a component in Fc receptor ("FcR") and B-cell receptor signaling pathway. ITP is a complex autoimmune bleeding disorder, leading to a reduced platelet level in the peripheral blood. ITP can also impact on patients' quality of life due to fatigue, restrictions on activities and anxiety. The ESLIM-01 trial results published by The Lancet Haematology suggest that sovleplenib could be a potential treatment option for patients with ITP who received at least one prior therapy.

ESLIM-01 is a 2:1 randomized, double-blind, Phase III study conducted in 188 adult patients with primary ITP who had received at least one previous anti-ITP treatment (NCT05029635). The study demonstrated a clinically meaningful early and sustained durable platelet response in patients with primary ITP, with a tolerable safety profile and improvement in quality of life. The primary endpoint was met, with durable response rate of 48.4% (61/126) with sovleplenib compared to zero with placebo (p<0.0001), which was consistent across most pre-defined subgroups. In addition, overall response rates were 68.3% at 0–12 weeks and 70.6% at 0–24 weeks with sovleplenib, compared to 14.5% and 16.1% with placebo (p<0.0001). The median time to response was 8 days with sovleplenib compared to 30 days with placebo.

Further post-hoc subgroup analysis of the study demonstrated consistent clinical benefits across ITP patients regardless of prior lines of ITP therapies or prior TPO/TPO-RA exposure, including TPO/TPO-RA treatment types and number of prior regimens. Most patients were heavily pretreated with a median of four prior lines of ITP therapy. In patients who received four or more prior lines of therapy, the durable response rate was 47.7% with sovleplenib compared to 0% with placebo (p<0.0001). In addition, a majority of the patients had received prior TPO/TPO-RA. 74.6% of patients in the sovleplenib group had received prior treatment with TPO/TPO-RA, and analysis in this subgroup also demonstrated a significantly higher durable response rate of 46.8% with sovleplenib compared to zero with placebo (p<0.0001).

The safety profile of sovleplenib in ESLIM-01 was consistent with previously reported studies. The majority of treatment-emergent adverse events ("TEAEs") were mild or moderate in severity (grade 1 or 2). Grade 3 or above TEAEs were reported in 25.4% of patients with sovleplenib and 24.2% with placebo. Sovleplenib also significantly improved quality of life in physical functioning and energy/fatigue (p<0.05).2

The China National Medical Products Administration ("NMPA") granted Breakthrough Therapy designation for this indication and accepted the New Drug Application ("NDA") for review with Priority Review in January 2024. A dose-finding study in the U.S. is being planned (NCT06291415). HUTCHMED also initiated the registration stage of the Phase II/III clinical trial of sovleplenib in adult patients with warm antibody autoimmune hemolytic anemia ("wAIHA") in China in March 2024 (NCT05535933). HUTCHMED retains all rights to sovleplenib worldwide.

About ITP

ITP is an autoimmune disorder characterized by immunologic destruction of platelets and decreased platelet production. Patients with ITP are at increased risk of excessive bleeding and bruising.3 ITP is also associated with fatigue (reported in up to 39% of adults with ITP) and impaired quality of life.4,5,6,7,8 The incidence of primary ITP in adults is 3.3/100,000 adults per year with a prevalence of 9.5 per 100,000 adults.9 Based on this prevalence rate, approximately 110,000 patients are estimated to be living with primary ITP in China, in addition to 56,000 patients in the U.S., Germany, France, Italy, Spain, UK, and Japan. It has been estimated that as many as 145,000 patients are living with chronic ITP in major pharmaceutical markets excluding China.10

Adult ITP is a heterogeneous disease that can persist for years, even with best available care, and treatments are infrequently curative. Despite availability of several treatments with differing mechanisms of action, chronicity of disease continues to be a problem. Many patients develop resistance to treatment and thereby are prone to relapse.11 Thus, there remains a significant population of patients who have limited sensitivity to currently available agents and are in need of new treatments.

As platelet destruction in ITP is mediated by Syk-dependent phagocytosis of FcγR-bound platelets, Syk inhibition represents a promising approach to management of ITP.12

About Sovleplenib

Sovleplenib is a novel, selective inhibitor of Syk for once daily oral administration. Syk, a non-receptor tyrosine kinase, is a major component in B-cell receptor and FcR signaling and is an established target for the treatment of multiple subtypes of B-cell lymphomas and autoimmune disorders.

Sovleplenib is currently under clinical investigation and its safety and efficacy have not been approved by any regulatory authority.

HUTCHMED retains all rights to sovleplenib worldwide. In addition to ITP, sovleplenib is also being studied in warm antibody autoimmune hemolytic anemia (NCT05535933) and indolent non-Hodgkin's lymphoma (NCT03779113).

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