Sanofi's Innovative RNAi Therapy Fitusiran Granted Clinical Trial Approval in China for Adolescent and Adult Hemophilia Patients

Medicine Overview / Report

On August 13, the latest public notice from the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration indicated that the clinical trial application for fitusiran injection, an investigational new drug developed by Genzyme, a subsidiary of Sanofi, has received implicit approval. The indicated indication is for the prevention or reduction of bleeding episodes in adult and adolescent patients aged 12 years and older with hemophilia A or B, with or without inhibitory antibodies.

▲Source: CDE Official Website

This is a novel RNAi therapy jointly developed by Genzyme Corporation and Alnylam Pharmaceuticals. Many may be familiar with the latter, as it was responsible for patisiran, the world’s first RNAi therapy approved by the U.S. FDA in August 2018. Fitusiran represents another highly anticipated RNAi therapy from this company.

Hemophilia is an inherited bleeding disorder characterized by the inability to produce thrombin at levels required for effective coagulation, leading to recurrent bleeding in joints, muscles, and major internal organs. Public data indicate that approximately 200,000 people worldwide are diagnosed with hemophilia A or B.

Currently, the standard treatment for patients with hemophilia includes replacement therapy targeting clotting factors, which can temporarily restore the body's clotting ability either prophylactically or "on-demand." However, more than one-third of patients with severe hemophilia A develop neutralizing antibodies against the replacement factors, leading to very serious complications. Therefore, there is an urgent need for therapeutic options beyond standard replacement factors for these patients.

Fitusiran is a once-monthly subcutaneous RNAi antithrombin (AT) therapy designed to lower AT levels, promote sufficient thrombin generation, and thereby restore hemostasis and prevent bleeding. Developed by Alnylam using its ESC-GalNAc conjugate technology, the therapy offers enhanced potency and durability with subcutaneous administration. Furthermore, it holds potential for the treatment of other rare bleeding disorders. As a strategic partner, Sanofi has invested significantly to support the development of this therapy.

Previously, Phase I clinical results of this therapy demonstrated preliminary safety and tolerability. Studies have shown that fitusiran reduces antithrombin (AT) levels and increases thrombin generation in patients with hemophilia A and B without inhibitors. Subsequent Phase II studies indicated that the safety and tolerability profile of fitusiran remained encouraging during concomitant administration of replacement factors or bypassing agents, with no thromboembolic events reported. According to the latest data from ClinicalTrials.gov, five clinical trials of this therapy are currently ongoing, and we look forward to positive outcomes from these studies.

▲ Screenshot source: ClinicalTrials.gov

The landscape of hemophilia treatment in China has undergone significant changes over the past two years. With the continuous advancement of a series of reform measures by regulatory authorities, an increasing number of innovative therapies have reached patients at an accelerated pace.

We congratulate the approval of this innovative RNAi therapy for hemophilia for clinical trials in China, and look forward to its further advancement in clinical research to benefit more hemophilia patients as soon as possible.

Original Title: Express | Sanofi's Innovative RNAi Therapy Approved for Clinical Trials in China to Treat Hemophilia

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