Efgartigimod Alfa Injection Approved in China for Generalized Myasthenia Gravis

Zai Lab Limited and argenx have announced that the National Medical Products Administration (NMPA) of China has approved the Biologics License Application (BLA) for efgartigimod alfa injection (subcutaneous injection), also known as efgartigimod SC. This subcutaneous injectable, marketed in dosages of 1,000mg (5.6ml) per vial, is designed as an adjunct to standard therapy for treating adult patients in China who suffer from generalized myasthenia gravis (gMG) and test positive for anti-acetylcholine receptor (AChR) antibodies.

Rafael G. Amado, M.D., President and Head of Global Research and Development at Zai Lab, expressed satisfaction with the approval, calling it a significant milestone. He emphasized that the new treatment would offer increased flexibility for gMG patients, simplifying therapy regimens and making treatment more accessible within communities. He also acknowledged the NMPA's thorough evaluation and recognition of the therapy's unique profile and the pressing medical needs in China.

Tim Van Hauwermeiren, Chief Executive Officer of argenx, also hailed the approval as a crucial step in expanding the reach of their transformative medicine to new patient populations globally. He praised Zai Lab's efficient launch strategy, which successfully brought 2,700 new patients onto VYVGART IV treatment in the first quarter of 2024. Van Hauwermeiren noted that the flexibility of the 30-to-90 second subcutaneous injection would make the treatment more convenient and appealing to new patients in China. He expressed optimism about continuing the partnership to broaden their presence in one of the world's fastest-growing markets, aiming to reach more individuals suffering from severe autoimmune diseases.

Dr. Xueqiang Hu, a Chief Physician in the Neurology Department at the Third Affiliated Hospital of Sun Yat-sen University, highlighted the significance of this approval for gMG patients in China. He pointed out that approximately 170,000 individuals in China live with gMG, and the availability of efgartigimod SC offers a more individualized treatment approach without compromising clinical benefits or safety. The global Phase 3 ADAPT-SC study demonstrated that efgartigimod SC had consistent benefits and safety compared to its intravenous counterpart, making it a meaningful advancement for the patient community.

The approval was based on the positive results from the Phase 3 ADAPT-SC study, which served as a bridging study to the Phase 3 ADAPT study that led to the approval of intravenous VYVGART for adult gMG patients. In the ADAPT-SC study, efgartigimod SC met its primary endpoint of noninferiority and showed a mean total IgG reduction of 66.4% from baseline at day 29, compared to 62.2% with intravenous efgartigimod. The safety profile was also consistent with the ADAPT study, with the most frequent adverse event being mild to moderate injection site reactions, which resolved over time.

Efgartigimod SC is under evaluation for treating other autoimmune disorders. In May 2024, the NMPA accepted a supplemental Biologics License Application (sBLA) with priority review for its use in chronic inflammatory demyelinating polyneuropathy (CIDP). The U.S. FDA approved efgartigimod SC for adults with CIDP in June 2024.

VYVGART (efgartigimod alfa injection) is a human IgG1 antibody fragment that targets the neonatal Fc receptor (FcRn), reducing circulating IgG autoantibodies. It is the first approved FcRn blocker for treating adults with gMG who are anti-AChR antibody positive. The subcutaneous version, efgartigimod SC, includes recombinant human hyaluronidase PH20 (rHuPH20) to facilitate subcutaneous delivery and is administered as a single injection over 30-to-90 seconds in cycles of weekly injections for four weeks.

Zai Lab holds an exclusive license agreement with argenx to develop and market efgartigimod in Greater China, including mainland China, Hong Kong, Macau, and Taiwan.