A phase 3 study among Chinese patients for an eye drug co-developed by Shanghai Henlius Biotech (HKG:2696) and Essex Bio-Technology (HKG:1061) reached the primary study endpoints, according to separate Wednesday filings with the Hong Kong bourse.

The two companies co-developed the HLX04-O injection for wet age-related macular degeneration patients.

The drug contains thee recombinant anti-vascular endothelial growth factor humanised monoclonal antibody, according to Essex's filing.

Wet age-related macular degeneration patients experience abnormal growth of blood vessels under the retina which could lead to rapid vision loss.

Shares in Essex surged nearly 11%, while that of Henlius fell 4% during late morning trading Thursday.