Deuterium drugs attract investment

Two deuterium drug companies reported deals on Jan. 19. Mumbai-based Sun Pharma announced that it would acquire the deuterium drug developer Concert Pharmaceuticals for $576 million. And the Belgian start-up DeuterOncology announced that it had closed a $6.1 million series A financing round.

Drugs made with deuterium, an isotope of hydrogen, take advantage of the fact that it’s harder to remove a deuterium from a carbon than it is to remove a hydrogen. Enzymes in the body’s metabolism often start degrading drugs by cleaving off their hydrogens. Because deuteriums are harder to pick off, the drugs could remain intact longer.

In the acquisition, Sun will get Concert’s lead candidate, deuruxolitinib, a kinase inhibitor for alopecia areata, an autoimmune disease characterized by hair loss. Concert has completed two Phase 3 trials with the drug, and Sun plans to submit a new drug application to the US Food and Drug Administration in the first half of this year, the companies say.

DeuterOncology will use the series A funding to advance its lead candidate, DO-2, into Phase 1 trials, the company says. DO-2, an inhibitor of the mesenchymal epithelial transition (MET) tyrosine kinase, is intended to treat lung cancer. Other inhibitors of the same kinase get converted quickly into metabolites that aren’t effective against MET, so they require high doses to be effective, and the metabolites have off-target effects, according to DeuterOncology CEO Timothy Perera. The strength of the deuterium bond means it’s harder to degrade DO-2, he says, and thus it should be effective at lower doses and be less toxic. DO-2 was originally developed at Janssen Pharmaceuticals, a subsidiary of Johnson & Johnson, but DeuterOncology now holds the license to develop it.

John Maxwell, the head of chemistry at Tango Therapeutics and former director of medicinal chemistry at Vertex Pharmaceuticals, thinks “the hype has faded” around deuterium drugs. Things were different when companies could patent deuterated versions of other companies’ drugs, he says, but that has been largely stopped. “Companies and chemistry teams have gotten wiser. And patent attorneys have the language they need to help protect against that kind of stuff. So I don’t think it’s as big of a thing as it was 7, 10 years ago,” Maxwell says.

In 2017, Vertex bought a cystic fibrosis drug candidate from Concert for $250 million. That compound (then CTP-656, now VX-561, or deutivacaftor) is a deuterated version of Vertex’s ivacaftor (Kalydeco). In Sept. 2022, Bristol Myers Squibb’s deucravacitinib (Sotyktu) became the first drug to be approved that was designed to include deuterium from the outset.