Recombinant human coagulation factor FⅦa-Fc fusion protein for injection (rhFVII-Fc, SS109) developed by Jiangsu Gensciences Inc. (Jiangsu Gensciences) received the notice of two clinical trial approvals from the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA) on September 20, 2022 for Class I new drug for the treatment of hemophilia patients with inhibitors of coagulation factor VIII or IX.

Jiangsu Gensciences successfully completed the Phase Ia clinical trial of SS109 in the first half of 2023 and obtained systematic human pharmacokinetic data and preliminary safety data. Based on these data, Jiangsu Gensciences initiated a Phase Ib/II clinical trial of SS109 for head-to-head pharmacokinetic comparisons with the representative drug Novoseven®, for further safety and efficacy evaluation. The first subject of this clinical trial was successfully enrolled on October 12, 2023 at the leading site, the Hematology Hospital of the Chinese Academy of Medical Sciences (Institute of Hematology, Chinese Academy of Medical Sciences).

Hemophilia is a bleeding disorder with X-chromosome-linked recessive inheritance. It is clinically classified as Hemophilia A and Hemophilia B, which are caused by genetic mutations in the coagulation factor VIII (FⅧ) and coagulation factor IX (FIX), respectively, triggering deficiencies of the corresponding coagulation factors. In the male population, the prevalence is about 1/5000 for hemophilia A and about 1/25000 for Hemophilia B; hemophilia A accounts for about 80% to 85% of all hemophiliacs, and hemophilia B accounts for 15% to 20%.

Hemophilia is often clinically manifested as spontaneous or trauma-related bleeding, mainly in the joints, soft tissues and muscles, which may result in lifelong disability in mild cases or be life-threatening in severe cases within a short period of time. Currently, there is no cure for hemophilia, and it is treated primarily by exogenous supplemental coagulation factor replacement therapies. The most serious complication of hemophilia treatment is the formation of neutralizing antibodies (inhibitors), which hampers the efficacy of replacement therapies. The production of inhibitors reduces or renders ineffective the efficacy of replacement therapies, making it difficult to continue conventional prophylaxis, leading to an increased incidence of bleeding in patients, a significant increase in the difficulty of bleeding treatment, and a further increase in the disability and mortality of hemophiliacs.

Current treatment for hemophiliacs with inhibitors is based on the strategy of bleeding control and removal of inhibitors. Hemophiliacs with inhibitors in China are currently treated with "alternative pathway" drugs (including genetically recombinant human activated coagulation factor VII (rhFⅦa) and prothrombin complex concentrate (PCC)) for hemostasis. According to the Guidelines for the Management of Hemophilia in China (2021), in case of mild or severe life-threatening bleeding, hemophiliacs with inhibitors are treated mainly with alternative pathway drugs (rhFⅦa and PCC), among which rhFⅦa is preferred for hemostatic treatment.

Currently in China, the only rhFⅦa drug approved and available is Novoseven®. Its short half-life results in the need for frequent infusions during bleeding therapy or inhibitor clearance-immune tolerance induction (ITI) therapy, thus increasing the pain and inconvenience for patients, and its high price leads to high treatment costs.

The rhFⅦa-Fc fusion protein long-lasting product (SS109) developed by Jiangsu Gensciences, as the only long-lasting rhFⅦa product under research in China, is based on Fc fusion protein technology and can effectively extend the half-life of rhFⅦa. The company's original two-headed homodimer Fc fusion technology greatly increases the in vivo half-life of activated factor VII while maintaining its hemostatic efficacy. Moreover, with significant cost and compliance advantages relying on its advanced manufacturing process and capacity, SS109 is expected to significantly lower the economic burden of patients and greatly improve the product accessibility. When SS109 is put on the market in the future, it is expected to break the monopoly of imported drugs, fully satisfy the patients' demand, improve patients' compliance, and lower the economic burden of the patients' families as well as the society, demonstrating great social significance.