NDA Acceptance in China

HUTCHMED Announces NDA Acceptance in China with Priority Review Status and Breakthrough Designation for Sovleplenib for the Treatment of Warm Antibody Autoimmune Hemolytic Anemia

Hong Kong, Shanghai & Florham Park, NJ - Wednesday, April 29, 2026: HUTCHMED (China) Limited ("HUTCHMED") (Nasdaq/AIM:HCM; HKEX:13) today announces that the New Drug Application ("NDA") for sovleplenib for the treatment of adult patients with warm antibody autoimmune hemolytic anemia ("wAIHA") who have had an insufficient response to at least one previous glucocorticoid treatment has been accepted for review and granted priority review by the China National Medical Products Administration ("NMPA"). Sovleplenib is a novel, selective, oral inhibitor targeting spleen tyrosine kinase ("Syk"), being developed for the treatment of immune diseases and hematological malignancies.

Autoimmune hemolytic anemia ("AIHA") is an autoimmune disorder characterized by the destruction of red blood cells ("RBCs") due to the production of antibodies against RBC. The incidence of AIHA is estimated to be 0.8-3.0/100,000 adults per year with an estimated prevalence of 17 per 100,000 adults and a death rate of 8‑11%.[1],[2] wAIHA is the most common form of AIHA,[3] accounting for about 75-80% of all adult AIHA cases.[4]

The NDA is supported by data from ESLIM-02, a randomized, double blind, placebo-controlled China Phase II/III study in adult patients with primary or secondary wAIHA who had relapsed or were refractory to at least one prior line of standard treatment. In January 2026, the Phase III part of the trial met its primary endpoint of durable hemoglobin (Hb) response rate within weeks 5 to 24 of treatment. The Phase III results will be presented at the upcoming European Hematology Association (EHA) Congress 2026.

Results from the Phase II part of the study published in The Lancet Haematology in January 2025 demonstrated encouraging hemoglobin benefit compared with placebo, with overall response rate of 43.8% vs 0% in the first 8 weeks, and overall response rate of 66.7% during the 24 weeks of sovleplenib treatment (including patients that crossed over from placebo) with a favorable safety profile.[5] Additional details of the study may be found at clinicaltrials.gov, using identifier NCT05535933.

Mr Johnny Cheng, Acting Chief Executive Officer and Chief Financial Officer of HUTCHMED, said, "We are pleased to have submitted the NDA for sovleplenib in wAIHA, securing both Priority Review and Breakthrough Therapy Designation from the NMPA. This marks the second indication for which we have submitted an NDA for sovleplenib and underscores its broad potential as a novel oral Syk inhibitor. We look forward to providing this much-needed option for wAIHA patients with few treatment alternatives, while strengthening our hematology portfolio with this valuable new indication."

The NMPA granted Breakthrough Therapy Designation to sovleplenib for the treatment of wAIHA in March 2026, as a potential new treatment for a serious condition for which there are no effective treatment options, and where clinical evidence demonstrates significant advantages over existing therapies.

About Sovleplenib and wAIHA

Sovleplenib is a novel, investigational, selective small molecule inhibitor for oral administration targeting Syk. Syk is a major component in B-cell receptor and Fc receptor signaling and is an established target for the treatment of multiple subtypes of B-cell lymphomas and autoimmune disorders.

The accelerated clearance of antibody-coated RBCs by immunoglobulin Fc-gamma receptor (FcγR) bearing macrophages is thought to be the pathogenic mechanism in wAIHA.[6] Activated Syk mediates downstream signaling of the activated Fc receptors in phagocytic cells, resulting in phagocytosis of RBCs.[7] In addition, activation of Syk through the B-cell receptor mediates activation and differentiation of B-lymphocytes into antibody secreting plasma cells.[8] Inhibition of Syk may have potential effects in the treatment of wAIHA through inhibition of phagocytosis and reduction of antibody production.

In addition to wAIHA, sovleplenib is also being studied in immune thrombocytopenia ("ITP"). Positive results from ESLIM-01 (NCT05029635), a Phase III trial in China of sovleplenib in patients with primary ITP, have been published in The Lancet Haematology. The NMPA accepted for review the resubmitted NDA filing for the treatment of ITP and granted it priority review in February 2026. According to IQVIA, China has 430,000 existing patients with 41,000 new ITP patients each year. About half of ITP patients fail to have satisfactory results from currently approved treatments such as TPO (thrombopoietin) /TPO-RAs (thrombopoietin receptor agonists).

HUTCHMED currently retains all rights to sovleplenib worldwide.

Medical Information

[1] Eaton WW, Rose NR, Kalaydjian A, Pedersen MG, Mortensen PB. Epidemiology of autoimmune diseases in Denmark. J Autoimmun. 2007; 29 (1):1-9. doi: 10.1016/j.jaut.2007.05.002.

[2] Roumier M, Loustau V, Guillaud C, et al. Characteristics and outcome of warm autoimmune hemolytic anemia in adults: new insights based on a single-center experience with 60 patients. Am J Hematol. 2014; 89 (9):E150-5. doi: 10.1002/ajh.23767.

[3] Cotran Ramzi S, Kumar Vinay, Fausto Nelson, Nelso Fausto, Robbins Stanley L, Abbas Abul K. Robbins and Cotran pathologic basis of disease. St. Louis, Mo: Elsevier Saunders; 2005. p. 637.

[4] Gehrs BC, Friedberg RC. Autoimmune haemolytic anemia. Am J Hematol. 2002; 69:258-271. doi: 10.1002/ajh.10062.

[5] Zhao X, Sun J, Zhang Z, et al. Sovleplenib in patients with primary or secondary warm autoimmune haemolytic anaemia: results from phase 2 of a randomised, double-blind, placebo-controlled, phase 2/3 study. Lancet Haematol. 2025;12(2):e97-e108. doi:10.1016/S2352-3026(24)00344-2

[6] Barros MM, Blajchman MA, Bordin JO. Warm autoimmune hemolytic anemia: recent progress in understanding the immunobiology and the treatment. Transfus Med Rev. 2010; 24(3):195‐210. doi: 10.1016/j.tmrv.2010.03.002.

[7] Barcellini W, Fattizzo B, Zaninoni A. Current and emerging treatment options for autoimmune hemolytic anemia. Expert Rev Clin Immunol. 2018; 14(10):857‐872. doi: 10.1080/1744666x.2018.1521722.

[8] Davidzohn N, Biram A, Stoler‐Barak L, Grenov A, Dassa B, Shulman Z. SYK degradation restrains plasma cell formation and promotes zonal transitions in germinal centers. J Exp Med. 2020; 217(3):e20191043. doi: 10.1084/jem.20191043.