Island Pharmaceuticals (ASX:ILA) strengthens regulatory position as FDA confirms animal rule pathway and PRV eligibility for Galidesivir

Island Pharmaceuticals has provided a detailed investor Q&A to clarify the significance of the recent FDA responses relating to the Galidesivir program.

These responses confirm that the Animal Rule pathway is the appropriate regulatory route for Marburg countermeasures and that Galidesivir would qualify for a Priority Review Voucher upon approval, which together represent major steps forward for the Company.

With investors seeking further detail on how these developments influence the regulatory timeline, program risk profile and commercial potential, Dr David Foster, CEO and Managing Director, has addressed the most common questions to ensure clarity and transparency.

Before addressing these questions, the Company highlights the importance of the FDA’s confirmation regarding Galidesivir’s development path:

“The FDA’s written response is a significant turning point because it removes a considerable amount of uncertainty around the regulatory path forward, as the regulator has confirmed that the Animal Rule is the appropriate approval pathway for Marburg countermeasures.”

How does the FDA response change the risk profile and timing for Galidesivir’s progression toward approval?

The FDA response substantially reduces regulatory uncertainty because it clarifies that the Animal Rule pathway is the correct and viable route for a Marburg treatment, which is essential given that traditional human efficacy trials are not possible for such a high mortality disease.

The FDA has also provided targeted guidance on and invited further communication regarding how the remaining development work should be structured, including key elements relating to clinical program design and the requirements for future non human primate studies.

As a result, Island Pharmaceuticals is now working with FDA to prepare a study protocol that aligns directly with FDA expectations, which will be submitted for review and is expected to receive a response within thirty days following submission.

This clarity allows the Company to proceed with the intent to commence the Galidesivir clinical program in the first quarter of the 2026 calendar year, creating a more confidence-based and clearly defined pathway toward an eventual New Drug Application.

What does Priority Review Voucher eligibility mean in practical financial terms for Island Pharmaceuticals?

The FDA’s confirmation that Galidesivir would qualify for a Tropical Disease Priority Review Voucher on approval is highly valuable because PRVs have historically sold for

significant amounts and are considered one of the most commercially meaningful incentives in the regulatory system.

“The confirmation that Galidesivir would qualify for a Tropical Disease Priority Review Voucher upon approval is highly meaningful because these vouchers have historically sold on the open market for between one hundred million and one hundred fifty five million United States dollars.”

This eligibility not only reflects confidence in the strength of Galidesivir’s underlying dataset, including the non human primate survival data, but also provides the Company with the prospect of a substantial strategic asset that becomes realisable upon approval, irrespective of product sales volumes.

What additional work is required before Island can submit a New Drug Application for Galidesivir?

Current FDA guidance indicates that at least one further non human primate study will be required before the New Drug Application package can be assembled.

Island Pharmaceuticals is preparing a set of clarifying questions, which can be submitted by the second of December, to ensure the program design fully reflects FDA expectations.

In parallel, the Company is engaging with Biosecurity Level 4 facilities, which are the only sites capable of conducting Marburg studies safely, in order to prepare for the next phase of research.

Once the updated study protocol is complete, it will be submitted to the FDA for review, and a response is expected within thirty days.

This process will shape the final clinical development pathway and ensure that Galidesivir moves forward with a well understood and regulator-aligned evidence base.

To illustrate the importance of this stage, Island notes:

“Based on the FDA’s current guidance, at least one additional non human primate study will be required before we can assemble an evidence package suitable for a New Drug Application, and while the precise details will be shaped by upcoming engagement with the FDA, the regulator has already provided valuable direction that allows us to begin planning.”

Is the Company funded to carry out the next phase of the program, including the planned animal study and regulatory engagements?

Island Pharmaceuticals is adequately funded for the next stage of its development program.

As at thirty September 2025, the Company held six point nine million dollars in cash and also has in the money options that are due to expire on the fourth of December 2025, which are likely to be exercised and may contribute an additional one million dollars.

This financial position provides the Board with confidence that the Company can progress its regulatory engagements, conduct the required non human primate study and complete the preparatory work for the clinical development program without distraction or financial interruption.

This funding flexibility ensures that the Company remains well positioned to integrate FDA guidance efficiently and maintain momentum along the Animal Rule pathway.

What is the potential commercial opportunity if Galidesivir is approved and included in government stockpile programs?

Government stockpile programs represent a substantial procurement opportunity for antiviral countermeasures, particularly in the United States where the Strategic National Stockpile and similar programs in allied nations collectively represent a multi hundred million United States dollar annual opportunity for filovirus treatments.

Marburg remains the only Category A biothreat without an approved treatment in the Strategic National Stockpile, which creates a clear unmet need.

Historical examples show that products approved under the Animal Rule have secured multi year stockpile contracts that have delivered lifetime values ranging from one hundred million to one point two billion United States dollars.

These contracts have typically remained active due to the ongoing requirement for national preparedness and rapid response capacity.

Island highlights this context with the following insight:

“Government stockpile programs provide a well established and substantial procurement channel for antiviral countermeasures, and this is particularly true in the United States where the Strategic National Stockpile and equivalent programs in allied countries represent a combined multi hundred million United States dollar annual procurement opportunity for filovirus countermeasures.”

Given that Marburg currently has no treatment in the stockpile, Galidesivir is positioned to potentially address a critical national security gap if approval is achieved.

Looking ahead

Thank you to our shareholders for your continued support as we advance this essential antiviral program.

The FDA’s written responses represent a significant milestone for Island Pharmaceuticals and establish a clear regulatory pathway that reduces development risk while strengthening the commercial outlook for Galidesivir.

We will continue working closely with the FDA, finalising our study design and progressing preparations with Biosecurity Level 4 partners as we move toward the commencement of our clinical development program in the first quarter of the 2026 calendar year.

Our focus remains firmly on disciplined execution, transparent communication and progressing Galidesivir toward approval and potential inclusion in strategic national stockpiles.

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