AsianFin -- Fosun Pharmaceutical Group has struck a licensing agreement worth up to $675 million with UK biotechnology firm Sitala Bio, granting it overseas rights to an innovative immune disorder drug currently in development.

Under the terms, Sitala will make an upfront payment of $25 million to Fosun Pharma and could pay up to $165 million in milestone fees tied to the progress of clinical trials and commercialization of FXS6837 and related compounds outside China, the Shanghai-based company announced yesterday.

If approved, the UK firm will also provide up to $480 million in sales-based milestone payments linked to annual net sales in international markets, alongside double-digit royalties on global sales. Additionally, Sitala will transfer a 10% equity stake valued at $5 million to a Fosun Pharma subsidiary as part of the deal.

FXS6837, a small-molecule inhibitor developed in-house by Fosun Pharma to treat immune regulatory disorders, is currently in Phase II clinical trials in China. As of July 31, the company had invested $16.8 million in research and development for the drug.