Chimerix Initiates Phase I HIV Study

Chimerix, Inc. has initiated a Phase I study of CMX157, a novel lipid conjugate of the nucleotide tenofovir with in vitro activity against both tenofovir-sensitive and tenofovir-resistant human immunodeficiency virus (HIV). CMX157 has the potential to increase efficacy and decrease toxicity as compared to tenofovir, and may allow for a ‘one pill, once-a-day’, fixed-dose combination regimens for the treatment of HIV infection.

The Phase I dose-escalating study is designed to evaluate the safety, tolerability and pharmacokinetics of CMX157. Healthy volunteers will receive a single-dose of CMX157 (25 mg, 50 mg or 100 mg), a standard dose of tenofovir (as Viread) or placebo. The study will also evaluate levels of the active antiviral (tenofovir diphosphate) in peripheral blood mononuclear cells (PBMCs), which may provide insight into the potential efficacy of CMX157, as the levels of tenofovir diphosphate in PBMCs associated with the antiviral efficacy of Viread have been documented.

CMX157 is a new chemical entity created by applying Chimerix’s PIM (Phospholipid Intramembrane Microfluidization) Conjugate Technology to chemically modify tenofovir, the molecule underlying the prodrug Viread, an antiviral agent approved for HIV and chronic hepatitis B. Chimerix’s PIM Conjugate Technology improves the absorption and distribution profile of drugs, achieving higher intracellular levels of the active antiviral agent. In vivo toxicology studies show that high plasma levels of CMX157 can be achieved with minimal toxicities.