Island Pharmaceuticals (ASX:ILA) said that the US Food and Drug Administration (FDA) confirmed, in response to questions posed in a Type C meeting request, that the animal rule pathway is appropriate for the approval of Marburg virus countermeasures, and that its antiviral drug candidate Galidesivir would qualify for a tropical disease priority review voucher on approval, according to a Monday Australian bourse filing.

The animal rule allows drugs to be approved based on efficacy demonstrated in well-controlled animal studies when human trials are unethical or not feasible.

The regulator provided guidance on the clinical program design. The company will incorporate all the US FDA guidance into Galidesivir's clinical development pathway.

The firm plans to begin the Galidesivir clinical trial program to advance approval in the first quarter of 2026. It has the opportunity to submit questions to the US FDA by Dec. 2.

Its shares jumped 24% in recent trading on Monday, earlier reaching an all-time high.