Concert Pharmaceuticals, the Lexington, MA-based company that chemically modifies existing drugs to make them more attractive, has started human testing of an HIV medication which it hopes will help GlaxoSmithKline wrestle back market share it has been losing to Gilead Sciences, the world’s largest maker of HIV drugs.
Concert will receive a $12 million payment from GlaxoSmithKline for starting the trial of a drug it calls CTP-518. It’s one small piece of the collaboration announced in June that could be worth more than $1 billion over time to the smaller company. I heard about this bit of news, and what it means strategically to Concert, when I visited CEO Roger Tung at the company’s office last week.
The basic idea is to take a common protease inhibitor, Bristol-Myers Squibb’s atazanavir (Reyataz), and swap out a few hydrogen atoms on the molecule with deuterium atoms. This is supposed to retain the drug’s viral killing punch, while making it last longer in the body. That’s desirable because it could allow doctors to quit prescribing a booster drug from Abbott Laboratories called ritonavir that adds cost, complexity, and hassles, Tung says. If the Concert drug is able to remain potent long enough in the bloodstream on its own, then it could be combined with other antivirals to create a convenient once-daily pill to compete with Gilead Sciences’ efavirenz emtricitabine tenofovir (Atripla), a drug that has helped Gilead surpass Glaxo as the world’s leading maker of HIV drugs the past couple of years.
“Doctors don’t like prescribing ritonavir, and patients don’t like taking it,” Tung says. “Our hope is to take a great drug and make it more tolerable and easier to take. The idea is to be the most tolerable, best-in-class HIV inhibitor.”
Without going too far into how this works, Concert says the deuterium atoms it is swapping into CTP-518 are supposed to form stronger bonds to the rest of the molecule than the traditional hydrogen bonds. By creating a more bulletproof package that stands up to the usual digestive processes, a greater amount of the drug and desirable metabolic byproducts are supposed to make it through the intestines and into the bloodstream, Tung says. That means the Concert drug should cause less irritation in the gut that can lead to diarrhea and nausea, and that it can use lower doses to get the same amount of drug into the bloodstream.
Getting rid of the ritonavir booster drug is important, Tung says, because
