Nucleotide arms race
Idenix nucleotide analog fills Merck gap in race for pan-genotype HCV regimen
The acquisition of Idenix Pharmaceuticals Inc. will fill a hole in Merck & Co. Inc.'s HCV toolbox and give the pharma a chance to develop an interferon-free regimen that can treat all patients at the same dose regardless of HCV genotype, HIV co-infection or other co-morbidities.
The $3.9 billion acquisition will put Merck in second place behind Gilead Sciences Inc. in the race to develop a pan-genotype regime. But the pharma thinks its combination will have a shorter duration of therapy than the Gilead regimen.
"Our goal is a single, universal regimen that is highly effective, well tolerated, and the same for all genotypes," said Eliav Barr, VP of infectious disease at Merck Research Laboratories.
The key asset in the deal is Idenix's IDX21437, a uridine nucleotide analog HCV NS5B polymerase inhibitor. A nuc is a must-have for any pan-genotypic regimen, and while Merck has its own, the Idenix compound is more advanced.
IDX21437 is in Phase I/II testing and is the second-most advanced once-daily nuc behind Gilead's marketed Sovaldi sofosbuvir.
Sovaldi is approved as part of an IFN-sparing regimen for genotypes 1 and 4. It is approved in IFN-free regimens of varying duration for genotypes 2 and 3 and for genotype 1 patients who can't tolerate IFN.
In the pan-genotype setting, Gilead is testing Sovaldi as part of different IFN-free combinations in a Phase II trial.
At the earliest, Merck would be starting Phase II trials of IDX21437 in a pan-genotype cocktail next year. However, based on the potency of the internal pipeline compounds Merck plans to combine with IDX21437, plus early clinical data reported by Idenix, the pharma hopes to shorten the duration of treatment to four or six weeks.
The duration of therapy in Gilead's trial is eight weeks.
According to Merck, a shorter duration and