A Phase I trial of Replicate Bioscience’s self-replicating RNA-based vaccine for rabies has elicited an immune response against a disease that the World Health Organization (WHO) describes as virtually 100% fatal.
Results from the randomised, open-label clinical trial (NCT06048770) found a single dose of RBI-4000 prompted an immune response with a WHO-established immune threshold of protection against rabies across all dose levels tested.
Published in the journal Nature, the trial enrolled 89 healthy volunteers between ages 18 to 45 who received doses of either 0.1mg, 1mg, or 10mg at two US sites. Results saw RBI-4000 generating an immune response comparable to the current standard of care, Bavarian Nordic’s RavAvert. No serious adverse events were observed.
Parinaz Aliahmad, head of research and development at Replicate, said: “These clinical results position RBI-4000 as a promising alternative capable of inducing rabies protective immunity at unprecedentedly low doses and with a single dose.
“Furthermore, the data showcase RBI-4000's favourable safety profile, which we attribute to our optimised and scalable manufacturing processes. We are encouraged by the strength of the robust clinical data package supporting the continued development of RBI-4000 and look forward to advancing it into further clinical studies."
Rabies is a tropical zoonotic disease, meaning it can be transmitted between humans and animals with the illness becoming inevitably fatal once clinical signs begin to show. Rabies deaths are, however, preventable in early stages using a method known as post-exposure prophylaxis (PEP), which aims to prevent the virus from reaching a patient’s nervous system.
While much of Europe and the US have been able to declare themselves rabies-free, the virus persists in 150 countries, mostly throughout Asia and Africa. The WHO estimates that there are approximately 59,000 deaths from rabies annually, 40% of those are children.
Research by GlobalData found that the global market for rabies vaccines in 2024 totalled $238m, with that figure forecasted to rise to $377m by the end of 2030. A report found that, compared with other vaccines used for travel purposes, rabies vaccines are associated with high costs due to their long-term dosing regimen.
GlobalData is the parent company of Clinical Trials Arena.
Elsewhere in the field of rabies vaccines, YS Biopharma has seen its rabies vaccine, Pika, meeting its primary endpoints in a Phase III trial.
