Opthea phase 3 clinical trial, COAST, in patients with wet age-related macular degeneration fails to meet primary endpoint

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Opthea announced results from COAST, its phase 3 clinical trial in patients with wet age-related macular degeneration (wet AMD).

COAST (Combination OPT-302 with Aflibercept Study) evaluated sozinibercept (2 mg) every 4 or 8 weeks in combination with aflibercept (2 mg), as per label, every 8 weeks after a loading phase for the treatment of wet AMD. According to the company, the trial did not meet its primary endpoint of mean change in best corrected visual acuity (BCVA) from baseline to week 52.

In wet AMD patients with minimally classic and occult lesions, participants receiving sozinibercept combination therapy with a dosing regimen of every 4 weeks (n=296) or every 8 weeks (n=297) achieved a mean change in BCVA of 13.2 or 13.2 letters from baseline to week 52, respectively, compared to 3.8 letters with aflibercept monotherapy (n=299).

In the overall population, participants receiving sozinibercept combination therapy with a dosing regimen of every 4 weeks (n=333) or every 8 weeks (n=330) achieved a mean change in BCVA of 13.5 and 12.8 letters from baseline to week 52, respectively, compared to 13.7 letters with aflibercept monotherapy (n=330).

The company noted in a press release that following the negative results, the company has been assessing its rights and obligations under its Development Funding Agreement (DFA) with the investors under the DFA, among others. The company stated that it is possible that under the DFA, it could become required to pay amounts to the DFA investors that would have a material adverse impact on the solvency of the company.

Furthermore, it was stated that certain instances and events may result upon the termination of the DFA, which would result in Opthea paying DFA investors up to 4 times the amounts paid to the company under the DFA. Termination of the DFA can be triggered by the inability of Opthea to fund development costs, failure by Opthea to continue to use commercially reasonable efforts to develop sozinibercept, Opthea’s insolvency, or disagreement with the DFA investors, among other events.

The company noted that its board of directors has been in active discussions with the DFA investors to explore possible options for the company “in respect of its clinical trial program and with a view to identifying whether there is a pathway that represents the best outcome for the company and its shareholders.”

Opthea also stated that at this stage, no decision has been taken with respect to either trial (COAST or ShORe), including whether to discontinue activities for the COAST trial or accelerate and unmask the ShORe trial.

The company stated in the press release that “there remains material uncertainty as to Opthea's ability to continue as a going concern.”

References:

1. Opthea announces COAST phase 3 trial topline results. Opthea. Published March 24, 2025. Accessed March 24, 2025. https://ir.opthea.com/news-releases/news-release-details/opthea-announces-coast-phase-3-trial-topline-results