ContraVir doses first patient in Phase Ib trial of CMX157 to treat HBV

ContraVir Pharmaceuticals has treated the first healthy volunteer in the Phase Ib portion of its Phase Ib/IIa multiple ascending dose clinical trial of its new, highly potent lipid conjugate of tenofovir, CMX157, to treat hepatitis B virus (HBV) infection.

Phase Ib of the trial will enrol 50 healthy volunteers assigned to one of five sequential, ascending CMX157 dosing cohorts.

Participating subjects will receive two weeks of a once-daily dose of either 5mg, 10mg, 25mg, 50mg or 100mg of CMX157 or placebo; eight per cohort receiving CMX157 and two per cohort receiving placebo.

The trial aims to assess the safety, tolerability and pharmacokinetic profile of CMX157.

The beginning of each higher dose cohort will proceed following review of data from the previous cohort, and an independent review will be conducted by a Data Safety Monitoring Board (DSMB) between the 25mg and 50mg cohorts at the midpoint of Phase I.

After the DSMB review, the company expects to start Phase IIa in parallel with the continuing of Phase Ib.

Phase IIa will enrol 60 treatment-naïve patients with chronic HBV infection to compare CMX157 to tenofovir DF (TDF), which is marketed by US-based biopharmaceutical company Gilead Sciences as Viread.

This study section will also include a sequential dose escalation, with ten patients per cohort receiving four weeks of a once-daily dose of either 5mg, 10mg, 25mg, 50mg or 100mg of CMX157, and two patients per cohort receiving 300mg of TDF, the standard dose of Viread.

In Phase Ib l, beginning of each higher dose cohort will follow review of the data from the previous cohort and there will be a DSMB review between the 25mg and 50mg CMX157 cohorts.

ContraVir CEO James Sapirstein said: "Dosing the first healthy volunteer in the CMX157 Phase Ib/IIa clinical study is a significant milestone.

"We're confident this trial will build upon the safety database that was already established in a completed Phase I study.

"Concurrently, we are preparing to launch the Phase IIa portion of our study, which will evaluate the antiviral activity and safety of CMX157 in patients diagnosed with HBV, in the second quarter of 2016."

Currently, the company is also involved in the development of its clinical drug, FV-100, which an orally available nucleoside analogue prodrug that is being developed to treat herpes zoster, or shingles, and is currently in Phase III clinical development stage.