Antiviral Being Used in Current Ebola Outbreak Advances Through Dual Development Strategy

Island Pharmaceuticals is collecting its first prospective human clinical data on investigational antiviral galidesivir during the ongoing Bundibugyo Ebola outbreak. Deployed under the World Health Organization's Monitored Emergency Use of Unregistered and Investigational Interventions (MEURI) framework, galidesivir is being used in a setting where no approved therapies currently exist, allowing researchers to evaluate its safety, virological activity, and clinical performance in patients with active disease. In an interview with Contagion, David Foster, PhD, chief executive officer of Island Pharmaceuticals, discussed how the MEURI program complements the company's FDA Animal Rule development strategy, which relies on efficacy data from nonhuman primate models for diseases where traditional human efficacy trials are not feasible. Foster also highlighted galidesivir's potential as a broad-spectrum antiviral against multiple filoviruses—including Ebola, Marburg, and Sudan virus—and emphasized the importance of global collaborations in accelerating investigational therapies during public health emergencies.

Contagion: Galidesivir is being deployed under the WHO's MEURI framework during the Bundibugyo Ebola outbreak. What makes this program unique, and what are your primary objectives for collecting clinical and safety data in this real-world setting?

Foster: This is the first opportunity to evaluate galidesivir in patients during an active Ebola outbreak, in a setting with a critical unmet medical need. Under the WHO's MEURI framework, investigational therapies can be made available when no approved treatment exists, which is particularly important for Bundibugyo Ebola, where there are currently no approved therapeutics.

For Island, this is a rare opportunity to generate prospective human clinical data in the intended disease setting while supporting frontline outbreak response efforts. Our primary objectives are to collect clinical, safety, and virological data; better understand how galidesivir performs in patients with active disease; and build on the extensive efficacy data already generated in animal models.

Importantly, very few filovirus programs are able to generate both prospective human outbreak data and controlled nonhuman primate efficacy data in parallel.

Contagion: Island Pharmaceuticals has emphasized that Galidesivir is advancing through both the FDA Animal Rule pathway and the MEURI program. How do you see these two development strategies complementing one another?

Foster: We describe this as a dual development strategy, with each pathway providing different but complementary evidence. The FDA Animal Rule pathway remains our principal regulatory route and is designed for diseases where traditional human efficacy trials are not feasible. FDA has already confirmed that the Animal Rule is an appropriate pathway for the galidesivir filovirus development program.

At the same time, the MEURI program allows us to collect prospective human efficacy, safety, and virological data during an active outbreak. While these data are not intended to replace Animal Rule requirements, they provide real-world evidence from the actual disease setting and can enhance our understanding of galidesivir's clinical profile.

Together, these two pathways combine prospective human clinical experience with controlled nonhuman primate efficacy studies, creating what we believe is one of the strongest development approaches available for a broad-spectrum filovirus countermeasure.

Contagion: With Uganda now reporting both Ebola and Marburg virus activity, how important is the development of broad-spectrum antivirals, and what has preclinical research shown about Galidesivir's potential against multiple filoviruses?

Foster: The current situation in Africa highlights exactly why broad-spectrum antivirals are so important. Existing Ebola countermeasures are largely strain-specific, and there are currently no approved therapeutics for Marburg virus disease, Bundibugyo Ebola virus disease, or Sudan virus disease. Meanwhile, outbreaks increasingly involve rare or divergent strains that existing countermeasures may not adequately address.

Galidesivir was originally developed as a broad-spectrum direct-acting RNA polymerase inhibitor and has demonstrated activity against multiple filoviruses, including Ebola, Marburg, and Sudan virus. Across a range of preclinical studies, galidesivir has shown robust antiviral activity and meaningful survival benefits in animal models of both Ebola and Marburg infection, including treatment initiated after infection.

What makes galidesivir notable is its potential as a multi-filovirus countermeasure. Rather than pursuing a single-strain solution, we are working toward a platform capable of addressing multiple high-consequence viral threats using a drug that can be administered intravenously or intramuscularly and is well-suited for outbreak settings.

Contagion: Island's role is limited to supplying the investigational drug while government and institutional partners oversee the program. How has this collaborative model with the Uganda Ministry of Health, the ACCEPT-Africa Consortium, and the Infectious Diseases Institute facilitated rapid deployment during an outbreak?

Foster: This program demonstrates the value of strong partnerships during a public health emergency. The Uganda Ministry of Health, the ACCEPT-Africa Consortium, the Infectious Diseases Institute, local ethics committees, and international partners have worked together to create the framework necessary to rapidly deploy an investigational therapy during an active outbreak.

Island's role is focused on supplying galidesivir and supporting the broader scientific effort, while local public health authorities and clinical partners oversee implementation and patient care. That division of responsibilities allows each organization to contribute its expertise and has enabled a rapid but appropriately governed response.

More broadly, this collaboration illustrates how public, academic, and industry partners can move quickly together when an outbreak demands it.

Contagion: If the MEURI program generates encouraging safety and virological findings, what are the next milestones for Galidesivir, and what would need to happen before the therapy could become available more broadly for future Ebola or Marburg outbreaks?

Foster: The next major milestones remain centered on advancing galidesivir through the FDA Animal Rule pathway. This includes additional nonhuman primate studies, particularly in Marburg virus models, continued engagement with FDA, and completion of the remaining studies necessary to support a registration-quality package.

If the MEURI program generates encouraging safety, virological, or clinical observations, those data could provide important supportive evidence from the intended disease setting and further strengthen the overall development package.

Beyond regulatory approval, we see a significant opportunity to support global biodefense and pandemic preparedness initiatives. Subject to successful development and regulatory review, galidesivir could become eligible for government procurement and stockpiling programs in the United States and internationally. Ultimately, our goal is to provide a broadly acting antiviral countermeasure that can help protect against future Ebola, Marburg, and other filovirus outbreaks.

Editor’s Note:
And just yesterday, Island Pharmaceuticals signed a Statement of Work with Texas Biomedical Research Institute to advance development of galidesivir for Marburg virus disease under the FDA's Animal Rule pathway. The collaboration represents the second phase of the company's dose optimization program, complementing an ongoing study at the US Army Medical Research Institute of Infectious Diseases by evaluating treatment initiation at later stages of infection to help determine the minimally effective dose.

Together, the studies are expected to generate the pharmacokinetic, efficacy, and treatment-timing data needed to finalize the design of a planned pivotal Animal Rule efficacy study and support future FDA discussions. The Texas Biomed study is scheduled to begin in early 2027.