CSPC's RSV vaccine clears FDA for US trials weeks after China approval

SYS6057, a recombinant respiratory syncytial virus (RSV) vaccine candidate developed by CSPC Pharmaceutical Group (HKEX: 01093), has received FDA clearance to begin clinical trials in the US, less than a month after China's National Medical Products Administration (NMPA) granted the same authorization on 30 July 2026. The back-to-back regulatory clearances give the Hong Kong-listed company a simultaneous development path in two of the world's largest markets for RSV prophylaxis in older adults.

SYS6057 combines the RSV prefusion F (Pre-F) protein antigen with a proprietary second-generation nano-adjuvant system. CSPC says the adjuvant uses a different nanocarrier compared with its earlier RSV vaccine candidate, conferring distinct physicochemical and immunological properties. Preclinical data, according to the company, showed the vaccine can simultaneously elicit high-titre neutralising antibodies and cellular immune responses — a dual-arm immune profile the company attributes to adjuvant optimization. No clinical efficacy or safety data have been disclosed.

The planned clinical development in both countries targets prevention of RSV-associated lower respiratory tract disease in adults aged 60 and older. Trial design, participant numbers, dosing, and primary endpoints have not been disclosed.

CSPC enters a market where three RSV vaccines are already approved in the US for older adults: GSK's Arexvy (RSVPreF3-AS01E), Pfizer's Abrysvo (RSVpreF), and Moderna's mRESVIA (mRNA-1345), first approved in May 2023, May 2023, and May 2024, respectively. Arexvy and Abrysvo use prefusion F protein antigens, while mRESVIA uses mRNA encoding the prefusion F protein. SYS6057 similarly targets prefusion F but combines the recombinant antigen with CSPC's proprietary nano-adjuvant system, broadly resembling Arexvy's protein-plus-adjuvant strategy while using different adjuvant technology.

CSPC describes SYS6057 as its second recombinant protein vaccine candidate to enter clinical trials.

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