ContraVir Pharmaceuticals, Inc., a biopharmaceutical company, reported positive results from a third-party in vitro study that further validates CMX157's profile as a highly potent anti-hepatitis B drug.  

In this first head-to-head in vitro study, CMX157 compared favorably to tenofovir alafenamide fumarate (TAF), which was approved recently by the US Food and Drug Administration (FDA) as part of a four-drug combination therapy for HIV-1 (Genvoya), and is currently under development by Gilead Sciences Inc. (GILD) for treating chronic hepatitis B infection.  ContraVir recently initiated a phase 1/2a clinical study of CMX157, which is currently enrolling healthy volunteers and is anticipated to begin enrolling hepatitis B patients in the second quarter 2016.

The study compared the anti-hepatitis B activities of CMX157 and other tenofovir prodrugs, including tenofovir DF (Viread), in order to profile CMX157 among this important class of antiviral therapies.  The study findings revealed that CMX157 and TAF were similarly potent against hepatitis B virus (HBV), with CMX157 trending toward higher potency (EC50 = 9.3 ± 3.6 nM vs. 32.4 ± 17.1 nM for CMX157 and TAF, respectively; and EC90 = 186 ± 53 nM vs 474 ± 261 nM for CMX157 and TAF, respectively).  Furthermore, viral rebound studies showed that CMX157 demonstrates best-in-class duration of activity.  Nine days following incubation with HBV, using two different experimental conditions, one at equimolar and one at EC90 concentrations, CMX157 showed two- to three-fold reduced viral rebound compared to TAF.  The study also confirmed earlier results, as reported previously by ContraVir, regarding the significantly increased potency of CMX157 compared to tenofovir.

ContraVir is a biopharmaceutical company focused on the development and commercialization of targeted antiviral therapies with two candidates in mid-to-late stage clinical development. ContraVir's lead clinical drug, FV-100, is an orally available nucleoside analogue prodrug that is being developed for the treatment of herpes zoster, or shingles, which is currently in phase 3 clinical development.