By Marc Iskowitz

Vertex’s drug for treating hepatitis C virus, Incivek (telaprevir), is on course to smash the previous record for the biggest revenue-generating drug launch ever, analysts say.

The direct-acting antiviral generated $494.1 million in sales from its U.S. launch in May through the end of September, Vertex disclosed recently in an earnings report. The European Union approved the med, branded as Incivo, during the third quarter, as did Canada and Japan. With launches in all those markets under way through the fourth quarter, Incivek should reach a billion dollars in sales by year’s end, Wolters Kluwer inThought™ analyst Julie Hoggatt wrote in a recent research note.

Assuming Incivek goes blockbuster in less than nine months, that would be half the time it took for Genentech’s cancer med Avastin to reach the same sales level after approval in 2004, Hoggatt pointed out. Abbott’s Humira and Merck’s Januvia took about two years to earn blockbuster status after they hit the market in 2002 and 2006, respectively.

Rival hep. C antiviral Victrelis, which was approved a week before Incivek, is moving along a slower adoption curve. Merck reported sales through September of only $53 million for Victrelis. On a prescription basis, Incivek is consistently averaging 1,000 new scripts per week, compared to 300 per week for Victrelis. Incivek’s edge comes from a higher cure rate and a simpler and faster dosing regimen.

Based on the most recent quarterly numbers, Wolters Kluwer raised its Incivek revenue forecast to $1 billion in 2011 and $1.4 billion in 2012, and lowered its Victrelis estimate to $100 million in 2011 and $256 million for 2012.
Incivek is clearly winning the market share battle. The question now becomes, how will it sustain sales?

That will depend on the size of the remaining pool of untreated hep. C patients, Hoggatt wrote. Weekly new prescription counts for the two drugs are “consistent but not growing” over the last several weeks, suggesting that sales will plateau in 2012 for both drugs, she predicted.