ReViral’s RV521 fusion inhibitor produces highly significant reduction in viral load and clinical symptoms
London, UK, 5th February 2018 / ReViral, a UK-based biotech company focused on developing novel compounds targeting respiratory syncytial virus (RSV), today announced successful results from its Phase IIa placebo-controlled challenge trial in healthy adult subjects infected intranasally with respiratory syncytial virus (RSV). The study of RV521, an oral RSV fusion inhibitor, achieved all its primary and secondary endpoints (significantly reduced viral load, reduced total mucus weight and reduced clinical symptoms) compared to placebo.
RSV is a pathogen that infects the human respiratory tract, potentially leading to bronchiolitis and pneumonia. While most (but not all) otherwise healthy people recover from the virus, there is an increased risk of severe disease and death in premature infants, individuals with certain pulmonary conditions, the elderly and those who are immune suppressed. Globally RSV is responsible for more than 30 million infections every year.
"RSV infection in children, the immunocompromised and the elderly causes serious disease and there is a significant unmet medical need for treatment." said John DeVincenzo, MD, Professor of Pediatrics and Professor of Microbiology, Immunology, and Biochemistry, University of Tennessee School of Medicine and Medical Director of the Molecular and Viral Diagnostics Laboratories at Le Bonheur Children's Hospital. “Based on the reductions in RSV viral load and clinical symptoms, as well as the safety profile observed in this adult challenge study, clinical trials in naturally infected patients should now be expedited.”
Efficacy was evaluated in healthy volunteers who had demonstrated RSV infection before treatment. Among 66 subjects (randomised 2:1, RV521 to placebo), RV521 treatment rapidly reduced viral load to undetectable levels. Mean total mucus weight and total symptom diary score (daily reporting of symptoms such as stuffy nose, cough and sore throat) were also significantly lower for RV521 treated patients.
Safety analysis demonstrated no changes in laboratory-determined safety parameters and a balanced adverse event profile between and within both dose groups and placebo. No treatment-related serious adverse events occurred.
Eddy Littler, ReViral CEO, said, “RV521 has shown best in class properties as an RSV therapeutic including efficacy, dose and safety. The company will now move forward to a clinical study in infants”. The full data will be presented at the American Thoracic Society meeting in San Diego (18-23 May, 2018).
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About the Phase IIa Challenge Study
This study was a randomised, Phase IIa, double-blind, placebo-controlled study where healthy adult subjects were inoculated with RSV on Study Day 0. Subjects were treated with RV521 or placebo when infection was confirmed in the nasal wash, or on Study Day 5, whichever was achieved first. RV521 or placebo was administered orally twice daily for five consecutive days. Subjects were randomised to receive RV521 or matched placebo (2:1) at either 200 mg or 350 mg. Upon completion of dosing, subjects were observed until Study Day 12, at which time they were discharged.
RV521 is an orally available small molecule antiviral fusion inhibitor being evaluated for the treatment of RSV. RV521 blocks RSV replication by inhibiting RSV F-mediated fusion of RSV to the host cell. In phase I clinical studies RV521 showed excellent exposure with no serious adverse events (any adverse events that were reported were low grade, transient and did not require co-medication). Pre-clinical toxicity tests in adult and juvenile species have shown that RV521 has an excellent safety profile with an attractive margin over therapeutic doses.
ReViral is an antiviral drug discovery and development company focused on novel treatments for diseases caused by the respiratory syncytial virus (RSV). Founded in 2011, ReViral has an experienced R&D leadership team with a successful track record in antiviral drug discovery and development. The company has developed a novel antiviral programme targeting RSV fusion with highly potent, orally bioavailable inhibitors, strong drug-like characteristics and good pharmacokinetic properties offering versatility in route of administration. In 2012 ReViral won a significant Seeding Drug Discovery Award from the Wellcome Trust to develop its RSV fusion inhibitors to completion of IND filing. The company also has an RSV replication programme at an earlier stage of development and plans to expand its pipeline. In September 2015, ReViral completed a $21 million Series A funding round from a group of leading venture capital investors including Edmond de Rothschild Investment Partners, OrbiMed, and Brace Pharma Capital.