Positive initial results for srRNA rabies vaccine


Replicate Bioscience has shared positive results from the Phase I trial of RBI-4000, its srRNA-based rabies vaccine.

In this clinical trial, evaluating safety and immunogenicity of RBI-4000, participants received one or two doses of srRNA vaccine at low doses (0.1mcg, 1mcg or 10mcg).

At all assessed doses, RBI-4000 was well-tolerated and achieved a strong immune response, with protective virus-neutralising antibody titers above the World Health Organization (WHO)-defined immune surrogate level of protection against the rabies virus.

“These results have exceeded our expectations and show the power and potential of our srRNA technology and, we believe, de-risk our platform, manufacturing processes and pipeline,” said Nathaniel Wang, CEO of Replicate. “Achieving a broad therapeutic window is an important step-up from other existing mRNA and srRNA approaches, which allows us to expand applications of our self-replicating RNA to complex infectious diseases, off-the-shelf cancer vaccines, and as a platform for protein production.”

Preliminary data show that the surrogate metric of protection (RVNA≥0.5) was achieved in most subjects in the ultra-low 0.1mcg cohort; this is the lowest dose of any RNA technology reported to achieve surrogate of protection in humans.

”When we founded Replicate, we envisioned a class of RNA therapeutics capable of treating many more diseases and reaching many more patients. These data represent exciting progress towards realising that vision,” said Replicate Co-Founder and Board Chair Michael Ehlers, Chief Scientific Officer and Venture Partner at Apple Tree Partners (ATP).

Rabies remains a public health threat in several geographical regions and is designated an FDA Tropical Disease and NIAID Priority Pathogen.

RBI-4000 is an srRNA vaccine developed to stimulate virus-neutralising immune responses to rabies for prophylactic use. In preclinical studies, intramuscular administration of RBI-4000 provided durable protection against the rabies virus, inducing antibody production and robust virus-specific T cells.

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