CTP-518

CTP-518 is a novel HIV protease inhibitor from Concert Pharmaceuticals that replaces certain key hydrogen atoms of atazanavir with deuterium, a heavier, non-radioactive relative of hydrogen. The presence of deuterium slows hepatic elimination, resulting in a longer drug half-life and higher trough levels without the use of a boosting agent, such as ritonavir. In preclinical studies, the antiviral potency of atazanavir was fully retained but with markedly slower hepatic metabolism, providing an increase in half-life and plasma trough levels.

A randomised, double-blind, placebo-controlled phase Ib study was begun in November 2009. Participants will receive CTP-518 or placebo for 14 days. Researchers want to know if the inclusion of deuterium in CTP-518, taken once-daily, provides blood levels sufficient to suppress HIV replication when used as part of an antiretroviral regimen.

The company also has a patent on an investigational darunavir analogue drug. Concert has partnered with GlaxoSmithKline to develop CTP-518 and other deuterium-modified drugs.