Concert's selection of CTP-298 as the lead drug candidate means a $4 million milestone payment will go to the Lexington, Massachusetts-based biotechnology company. Depending on the progress of that compound, as well as others in Concert's drug program partnered with GSK, venture-backed Concert stands to gain up to $1 billion in payments from the British pharmaceutical giant whose U.S. headquarters are in Research Triangle Park, North Carolina.
The identification of a lead drug for treating HIV could be even bigger news for a GSK HIV program that has taken some hits this year. Teva Pharmaceutical in May received U.S. Food and Drug Administration approval on its generic version of GSK combination drug Combivir, which will strike at sales of one of GSK's top-selling drugs. GSK's HIV drug pipeline also suffered a hit in February when the FDA put a clinical hold on a drug candidate the company is developing with partner Idenix Pharmaceuticals (Nasdaq: IDIX ) . A hold remains on the compound.
GSK's accord with Concert was struck in 2009. Besides an HIV candidate, the deal also included a preclinical compound for chronic renal disease, as well as a third compound. These drug candidates contain deuterium, a nonradioactive relative of hydrogen. Concert has been researching "selective deuterium modification." Deuterium compounds are expected to have the same pharmacological activity as hydrogen, but because deuterium is heavier, it forms a stronger chemical bond to carbon. The company says using deuterium may improve safety, tolerability and efficacy of certain drugs.
CTP-518 was developed by replacing certain key hydrogen atoms of atazanavir, a protease inhibitor, with deuterium. Concert said that preclinical studies demonstrated that selective deuterium modification keeps the drug's antiviral potency, but also slows its metabolization in the body. That means that potentially, CTP-518 could be used without the need of a boosting agent, which is the current standard of care with HIV protease inhibitors. Concert expects to advance CTP-298 into clinical trials in HIV-positive patients next year.
GSK has the option to secure an exclusive, worldwide license for product candidates in the Concert program, which would mean that GSK would take over financing development and commercialization of the compounds. If GSK takes over CTP-518, it probably would go to ViiV Healthcare, the company formed jointly by GSK and Pfizer (NYSE: PFE ) in 2009 to focus exclusively on developing and marketing HIV treatments. London-based ViiV's U.S. headquarters are in Research Triangle Park.
Concert was founded in 2006. The company has raised more the $110 million in venture and institutional capital investments.