Oral Antiviral GHP-88310 Blocks Measles-Like Transmission in Ferrets

An oral antiviral candidate, GHP-88310, blocked airborne and direct-contact transmission of a measles-like virus in ferrets when given before or shortly after exposure, according to a study published July 24 in Nature Microbiology.¹ Researchers at the Center for Translational Antiviral Research (CTAR) at Georgia State University conducted the work, and the investigators are now preparing GHP-88310 for formal clinical testing in humans.¹

Georgia State study ties drug to outbreak control amid record US measles cases

The findings arrive as the United States is logging its highest measles case count in 35 years.² Because measles virus has no animal reservoir, researchers used canine distemper virus, a related morbillivirus that causes measles-like disease in ferrets, as a surrogate model for the study.¹

Prophylactic GHP-88310, dosed twice daily beginning 12 hours before exposure, fully protected direct-contact animals; none became infected or developed detectable virus in blood or nasal secretions.¹ In airborne-transmission experiments, the same twice-daily regimen given before exposure or up to 3 days after exposure completely blocked transmission, and all treated animals remained immunologically naive to the virus. A lower once-daily dose still resulted in complete survival, though those animals developed mild, transient infection and later seroconverted.

Treating already-infected source animals produced a separate benefit: therapy started 4 or 6 days after infection fully protected the treated animals and shortened the period during which they could transmit the virus by 5 days.¹ All direct and airborne contacts of treated source animals remained free of infection, indicating the treatment interrupted spread to others as well as protecting the treated animal.¹

"We were very excited to see that GHP-88310 given by mouth completely prevented airborne transmission in our ferret model of measles," said Carolin Lieber, PhD, a senior postdoctoral fellow in the Plemper lab and the study's first author. "This finding is unprecedented for a viral polymerase inhibitor and demonstrates the extraordinary antiviral potency of this drug."³

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How GHP-88310 Fits Into the Measles Drug Pipeline

GHP-88310 is a broad-spectrum inhibitor of the orthoparamyxovirus polymerase, the viral enzyme complex responsible for viral replication and protein synthesis.¹ It was developed from an earlier compound, GHP-88309, after researchers identified a tolerability limit of that compound in larger mammals; GHP-88310 was optimized to address that limit while preserving oral efficacy.⁴

No antiviral is currently approved to treat or prevent measles in humans, and the researchers note the ferret data have not yet been replicated with measles virus itself in an animal model, though a related compound previously showed efficacy against a clinical measles isolate in non-human primates.¹ Because measles has a longer incubation and prodromal period than canine distemper virus, the researchers say the therapeutic window in humans may prove even wider than what they observed in ferrets.¹

The study's authors are explicit that human pharmacokinetics, tolerability, and patient compliance with GHP-88310 remain unknown, since all efficacy data to date come from the ferret model rather than measles patients.¹ Whether caregivers would accept an antiviral for a measles-exposed child is also untested, though the researchers note that widespread use of vitamin A during the 2025 US outbreak suggests vaccine-hesitant families may still be open to other medical interventions.¹

"Silencing measles outbreaks quickly is essential to reestablish control over the virus," Richard Plemper, PhD, a Regents' Professor and director of the CTAR at Georgia State University and the study's senior author, said in a statement. "This study follows our recent development of the drug candidate GHP-88310. It demonstrates that the drug is suitable to augment traditional ring vaccination against measles."³

The measles resurgence driving interest in this research has been attributed largely to declining MMR vaccination rates, and the researchers frame GHP-88310 as a complement to, not a replacement for, vaccination-based outbreak control.¹ With no additional recalls or approvals expected soon, the drug's path forward runs through formal human clinical trials, which have not yet begun.¹

References

1. Lieber CM, Wolf JD, Ruckel CE, Harrison LA, Plemper RK. Antiviral GHP-88310 blocks contact-mediated and airborne transmission in a ferret model of measles-like disease. Nat Microbiol. Published online July 24, 2026. Accessed July 24, 2026. https://www.nature.com/articles/s41564-026-02419-y

2. Contagion Editorial Team. US measles cases set 35-year record with five months left in 2026. ContagionLive. Published July 23, 2026. Accessed July 24, 2026. https://www.contagionlive.com/view/us-measles-cases-set-35-year-record-with-five-months-left-in-2026

3. Georgia State University. New Drug Could Contribute to Stopping Measles Outbreaks. News release. Published July 24, 2026. Accessed July 31, 2026. https://news.gsu.edu/2026/07/24/new-drug-could-contribute-to-stopping-measles-outbreaks/

4. Lieber CM, et al. Developmental candidate GHP-88310/EIDD-3608 with high tolerability and oral efficacy in measles and respiratory paramyxovirus models. Sci Adv. 2026;12:eaef1594. Accessed July 24, 2026. https://www.science.org/doi/10.1126/sciadv.aef1594