Gilead gets its go-ahead for blockbuster hopeful Vosevi, but will 12-week dosing give it trouble?

Gilead is out with a brand-new second-line hepatitis C treatmentbut the length of its dosing schedule could set the company back down the line, one analyst predicts.

Tuesday, U.S. regulators green-lighted Vosevi, a three-drug cocktail combining sofosbuvir and velpatasviralready marketed together as pan-genotype medication Epclusawith new compound voxilaprevir. As Leerink Partners analyst Geoffrey Porges figures, the product will largely be used among patients who have already been treated with Gilead’s Harvoni or Epclusa or a competing regimen from rivals AbbVie or Merck.

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Gilead has set Vosevi’s price at $24,920 per bottle, putting it “at parity” with Epclusa at $74,760 for the 12-week course, Porges wrote in a note to clients. “Effectively Gilead is giving the third component of Vosevi free of charge to maintain the price point of their 12-week treatment course,” he said, noting that “given this label and position in the treatment hierarchy, Gilead could have priced Vosevi higher and probably not lost significant share.”

While Harvoni, for one, boasts a cure rate above 96%leaving only a fraction of the population eligible for Vosevi treatmentsome industry-watchers think the Gilead newcomer has potential to rake in blockbuster sales. Evaluate Pharma, in its World Preview 2017, pegged the med’s top-line potential at $1.1 billion by 2022.

There’s just one problem, the way Porges sees it. Vosevi’s U.S. approval doesn’t include the 8-week treatment duration previously recommended for a green light in Europe. And that omission will put Gilead “at a competitive disadvantage” to nemesis AbbVie, which is expected to win a go-ahead for an 8-week course to treat all hep C genotypes.

A disadvantage is not what Gilead needs, especially with its hep C revenue freefall expected to continue--and worsen. Porges, for one, sees sales from the franchise shrinking to just $2.9 billion by 2021 as the new group of wonder meds cures more and more patients.

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Meanwhile, the company has said it’s scouting buys and tapped oncology as a field it would like to enter. So far, though, rumors that it may be interested in Tesaro seem to have faded away, and the company hasn’t yet publicly heeded repeated recommendations from Porges to look into nabbing Vertex or Incyte.