CStone Pharmaceuticals has completed the previously announced share subscription agreement through which a Pfizer affiliate subscribed for newly issued CStone shares at around $200m.
In September, CStone entered a multifaceted strategic partnership with Pfizer to develop and commercialise late-stage oncology therapies in China.
Hong Kong’s Listing Committee of the Stock Exchange approved the listing of 115,928,803 additional shares subscribed by Pfizer at around HK$13.37 ($1.725) per share.
Pfizer now owns almost 9.9% of stake in CStone.
The deal will extend financing to develop and commercialise CStone’s sugemalimab, an investigational anti-PD-L1 monoclonal antibody for high-incidence cancers, including lung, gastric and oesophageal cancers, among others.
Sugemalimab imitates the natural G-type immunoglobulin 4 (IgG4) human antibody and thereby reduces immunogenicity and toxicity risks in patients.
The drug has completed a Phase I dose-escalation study in China and demonstrated antitumor activity in multiple tumour types in the Phase Ia and Ib trials.
As part of the agreement, Pfizer will get an exclusive licence to commercialise the drug candidate in mainland China.
The companies will develop and commercialise additional oncology assets in the Greater China market.
They may also pursue on a selected basis joint in-licensing set up for these assets.
At the time of signing the agreement, Pfizer Biopharmaceuticals Group China acting president Pierre Gaudreault said: “This collaboration with CStone builds on that history by helping to develop a potential best-in-class PD-L1 treatment that we can commercialise upon approval.”
Clifford Chance was the legal advisor for Pfizer. Goldman Sachs acted as financial advisor for CStone while Cooley LLP served as legal advisor.