Innogen Pharmaceutical shares soared 275% in Hong Kong's grey market trading.

The diabetes and metabolic diseases-focused biopharmaceutical company aims to raise as much as $100 million in the share sale, the people said, asking not to be identified discussing a private matter.

China International Capital Corp. and Citic Securities Co. are joint sponsors of the offering, while Deutsche Bank AG and Macquarie Capital Ltd. are coordinators, the company has said.

Innogen markets a diabetes treatment in China and approval of its efsubaglutide alfa in January marked a first for a domestically developed product, according to its prospectus. It is also testing efsubaglutide alfa, which belongs to a class known as GLP-1 drugs, in treating obesity and liver disease.

Innogen is looking to expand use of efsubaglutide alfa overseas as well, with plans to apply for licenses in Southeast Asia and Latin America, it has said.