Investing.com-- Shares of 3SBio Inc (HK: 1530 ) skyrocketed in Hong Kong trade on Tuesday after the company licensed an experimental cancer treatment to U.S. drugmaker Pfizer Inc (NYSE: PFE ), with the latter also taking an equity stake in the Chinese firm.

3SBio shares jumped 36.4% to HK$19.78 by the afternoon break, compared to an over 1% jump in the Hang Seng index.

Pfizer said on Tuesday that it had signed an agreement with 3SBio to license its SSGJ-707 drug candidate, which is being evaluated for several forms of rare cancer. The drug is currently undergoing clinical trials in China, and 3SBio plans to initiate a Phase III trial later in 2025.

Pfizer will pay $1.25 billion upfront and $4.8 billion if developmental milestones are met. The agreement grants Pfizer development, manufacturing, and commercialization rights to the cancer drug at a global scale, excluding China. Pfizer also has an option to obtain commercialization rights in China.

Separately, Pfizer said it plans to invest $100 million in 3SBio equity after the licensing deal closes, which is expected in the third quarter of 2025.

3SBio said the drug had been cleared by the U.S. Food and Drug Administration for its investigational new drug application.