Opthea (ASX:OPT) said its Combination OPT-302 with Aflibercept (COAST) study in patients with wet age-related Macular Degeneration, failed to meet its primary endpoint, according to a Monday filing with the Australian bourse.

The biopharmaceutical company is now reviewing its obligations under its development funding agreement (DFA) with investors, the filing said.

Under the DFA, Opthea could face repayment obligations of up to $680 million, if the agreement is terminated, due to factors like failure to advance its drug sozinibercept, used in the trial, the filing added.

Discussions with the DFA investors are ongoing for the parties to come to an agreement, including a negotiated settlement, however, no decision has been made regarding the continuation of the trial, the company said.

Given uncertainties regarding the trial and a reported $113.8 million in cash, the company added there is significant doubt about its ability to continue as a going concern.

Opthea requested an extension of trading suspensions on the Australian Securities Exchange until there is clarity related to the matter or trading resumes on March 31, the company added.