Concert Pharmaceuticals initiates Phase Ib HIV trial

Concert Pharmaceuticals has initiated a Phase Ib clinical study with CTP-518, its investigational oral HIV protease inhibitor for the treatment of HIV infection.

In connection with the start of this multiple ascending dose arm of the Phase I study, Concert will receive a $12 million milestone payment under the company's strategic alliance with GlaxoSmithKline (GSK).

The Phase Ib study will be used to assess the ability of CTP-518 to maintain acceptable therapeutic blood concentrations without a boosting agent such as ritonavir. It will also be used to determine doses for subsequent studies in HIV-infected patients.

The initial Phase I clinical trial is designed to evaluate the safety, tolerability and pharmacokinetics of CTP-518 in healthy volunteers after single and multiple doses. In addition, the Phase I study is intended to establish the pharmacokinetic enhancing effect of deuterium incorporation in CTP-518, and to determine whether CTP-518 dosed once-daily can maintain blood levels expected to be sufficient to suppress HIV replication when used as part of a standard three drug combination regimen.

The current standard of care is to co-administer all HIV protease inhibitors with ritonavir, except in patients who cannot tolerate ritonavir. The multiple ascending dose phase is a randomized, double-blind, placebo-controlled study in which study participants will receive CTP-518 or placebo for 14 days.

In June 2009, Concert and GSK announced a potential $1 billion strategic alliance to develop three deuterium-containing medicines, including CTP-518. Concert has responsibility for R&D activities of CTP-518 through completion of Phase I studies.

After the completion of the Phase I program, GSK may elect to obtain an exclusive, worldwide license to CTP-518. At such time, GSK would assume responsibility for development and commercialization.