Faltering Incivek growth might be an IMS data quirk

If you were disappointed by last month's prescription data for Vertex Pharmaceuticals' ($VRTX) hepatitis C drug Incivek, we have news for you. IMS Health says it's restating those numbers, citing missing data. Although specifics aren't yet available, analysts say they're expecting the revised figures to show prescription growth, rather than the slowdown earlier numbers showed.

"A significant portion of Incivek mail data was not reported to IMS," the market research firm said in a statement to clients (as quoted by Reuters). "This interruption should be resolved for the week ending 10/7/11." As ISI Group analyst Mark Schoenebaum told Bloomberg, "[p]eople are now thinking that maybe the trends weren't quite as flat as everybody was thinking."

Geoffrey Porges, a Bernstein analyst, said Vertex management indicated the new numbers are "likely to align the IMS data with [Vertex's] internal impressions of the market." Porges had questioned the accuracy of IMS's previous figures, as Reuters notes. He cautioned against over-reaction to the corrected numbers: "No... analyst with any measure of experience would make judgments about the performance of a launch and a product's long-term potential based on one, two or even three weeks of market audit data," he said.

Investors appear to have ignored that part of the memo. The Incivek launch has been closely watched, partly because it's one of two brand-new hepatitis C treatments that promise to revolutionize treatment. Furthermore, it's Vertex's first drug to hit the market. Every bit of data on Incivek sales has been analyzed by market-watchers. Vertex shares dropped on IMS's previous numbers--and the stock jumped back up by 20% when IMS said it would restate them. Hard sales numbers are due from Vertex when the company reports third-quarter results later this month.

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