So says Moody’s Investor Services in a forthcoming report. Given some of pharma’s challenges, though, this probably isn’t terribly surprising. “Approaching patent expirations between 2010 and 2012, a tougher regulatory climate, and a shift towards more aggressive financial policies create the potential for rating downgrades,” says Moody’s senior vp Mike Levesque, in a statement.

Most big US drugmakers rated by Moody’s face “significant” patent expirations between 2010 and 2012. And for most, cumulative patent expirations through 2012 affect more than 40 percent of current revenues - in some cases, more than 50 percent. In a fit of politeness, he aptly notes that pharma “will be challenged to replace maturing products with growth in newer products and upcoming pipeline launches.”

Then there’s the recent pace of FDA approvals, which is slower than prior years. Throw in a number of important new drug applications that have received non-approvable letters or approvable letters contingent upon new clinical trials, well, you have trouble. Wyeth comes to mind.

Finally, Levesque cautions that the industry’s financial policies, which were “previously conservative” and supported high credit ratings - may be subject to revision. A larger number of drugmakers “appear likely to consider larger acquisitions and share repurchase strategies in order to improve lagging shareholder returns,” he concludes.

Mitigating factors include cost restructuring programs (who isn’t cutting costs?), “cleaner” litigation profiles, and the success of several key products approved in 2005 and 2006, fueling growth for certain companies. These last two factors may refer to Merck, which has racked up a few Vioxx court victories and launched a couple of successful new meds.