Rational Vaccines Herpes Simplex Type 2 (HSV-2) Therapeutic Vaccine Candidate Demonstrates Efficacy in a Therapeutic Animal Study

NIH-funded study shows RVX201 exhibits robust protection against recurrent HSV-2 disease in guinea pig model

WOBURN, Mass. and OXFORD, England, July 8, 2022 /PRNewswire/ -- Rational Vaccines, a company focused on revolutionizing the treatment and prevention of herpes to eradicate the disease, today announced findings from an National Institutes of Health (NIH)-funded pilot study of RVX201, the Company's lead therapeutic vaccine candidate for herpes simplex virus type 2 (HSV-2). Results showed that treatment with RVX201 led to a reduction in recurrent genital lesions when compared to gD2-alum/MPL vaccine or placebo in vivo. In addition, RVX201 appears to generate a robust cellular immune response equivalent to that elicited by wild-type HSV-2 on Day 7 post-infection. Results showed that in comparison to no vaccine, animals that received RVX201 had the number of symptomatic days reduced by 45 percent while those that received gD2-alum/MPL vaccine only had a 24 percent reduction in symptomatic days.

"HSV is one of the most prevalent sexually transmitted infections. It is a cause of severe neonatal infections and a leading infectious cause of blindness in the Western world," said Konstantin G. Kousoulas, Ph.D., professor of virology and biotechnology, Louisiana State University (LSU) School of Veterinary Medicine, and vice president of scientific affairs at Rational Vaccines. "This therapeutic study shows that RVX201 confers significant protection from HSV-2 reactivation in latently infected animals. Specifically, results indicate significant reduction in viral titers and lesion scores in genital tissues of immunized guinea pigs in comparison to animals vaccinated with purified glycoprotein D (gD) with adjuvant. Additional prophylactic studies in mice have shown drastic protection against lethal HSV-2 genital challenge. Overall, these results as well as available limited human studies indicate that RVX201 can be an effective prophylactic and therapeutic vaccine approach against HSV-2/HSV-1 infections."

"In this pilot study we demonstrate that RVx's lead candidate, RVX201, performs significantly better than gD-2 when delivered via the same route" said Dr. Edward Gershburg, Chief Technology Officer for Rational Vaccines. "RVX201 reduced recurrences and number of symptomatic days by almost two-fold when compared to placebo. These results are consistent with our earlier observations, and warrant further testing of this candidate in humans."

The herpes simplex virus (HSV), commonly referred to as herpes, is categorized into two types: herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). HSV-1 is the primary cause of oral herpes but can also cause genital herpes. HSV-2 is the primary cause of genital herpes. According to a 2020 report by the World Health Organization (WHO), herpes infects billions globally – about a half a billion people worldwide are living with genital herpes, and several billion have an oral herpes infection. Both HSV-1 and HSV-2 infections are lifelong.

While most herpes infections are asymptomatic, a significant number of people experience a range of symptoms that vary in frequency and severity. The most common symptoms for both types of herpes are painful blisters or ulcers. In addition, many patients experience debilitating neuralgia, skin splits, fissures, minor abrasions, erythema, fever, chills, and myalgias. Both viruses are most contagious during a symptomatic outbreak, but they can still be transmitted in the absence of symptoms.

There is no cure for herpes. There are no approved vaccines or immunotherapies or sufficiently reliable diagnostics currently available¹. Antiviral medications developed in the 1970s can help to reduce the severity and frequency of symptoms but cannot cure the infection.

Rational Vaccines is revolutionizing the treatment, prevention, and diagnosis of herpes and herpes-related diseases with its rationally engineered, live-attenuated viral immunotherapeutic and prophylactic vaccine candidates. Led by a team of world-renowned scientists, the Company is headquartered in Woburn, MA with locations in Miami, FL and Oxford, UK. For more information, please visit www.rationalvaccines.com

¹https:/www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus and Herpes - STI Treatment Guidelines (cdc.gov)
²https://pubmed.ncbi.nlm.nih.gov/16327322/  

SOURCE Rational Vaccines