Drug giant (NYSE: GSK) is betting up to $1 billion that Massachusetts-based Concert Pharmaceuticals has a successful product pipeline under development.

GSK, which maintains its U.S. headquarters in RTP, said Tuesday it would invest $35 million up front and as much as $1 billion overall in privately held Concert.

will grant to GSK rights to three drug development programs, including an HIV product scheduled to begin clinical trials this year. Another product could be a treatment for chronic kidney disease. The other potential drug was not disclosed.

Glaxo will invest $16.7 million in Concert and make another $18.3 million in upfront payments. GSK also agreed to royalties and milestone payments linked to product development.

Concert focuses of deuterium as a means to improve drug effectiveness.

“Deuterium is a safe, non-radioactive relative of hydrogen that can be isolated from sea water and has been used extensively in human metabolic and clinical studies,” the companies said in a joint statement. “Since deuterium is an isotope of hydrogen, deuterium-containing compounds are expected to have similar pharmacological activity as their hydrogen analogs. However, as deuterium is heavier than hydrogen, it therefore forms a stronger chemical bond to a carbon atom of a molecule. The stronger chemical bond obtained by selective deuterium modification may substantially improve the drug’s metabolic properties, potentially resulting in better safety, tolerability and/or efficacy.”

Concert, founded in 2006, has already raised more than $96 million in venture capital and other financing.

“This agreement marks GSK’s continued efforts to access the best science and technology platforms worldwide,” said Patrick Vallance, senior vice president for drug discovery at GSK. “We believe Concert’s approach to deuterium modification of medicines has broad potential to enhance certain drug properties and result in innovative new medicines.”