(Reuters) - ViroPharma Inc VPHM.O, a drug maker that specializes in rare diseases, has attracted interest from Sanofi SA (SASY.PA) and Shire PLC (SHP.L), Bloomberg reported on Friday, pushing shares of the company up 24 percent.
Reuters reported in June that the company, which has a market capitalization of $1.8 billion, had attracted interest from several pharmaceutical companies because of its pipeline of drugs.
ViroPharma started working on an auction after receiving an unsolicited approach, Bloomberg reported, citing unnamed sources.
Shares rose by $7.29, or 24 percent, to $38.76 in afternoon trading on the New York Stock Exchange.
ViroPharma director of investor relations Robert Doody said, "our corporate policy is that we never comment on rumors and speculation."
Sanofi spokesman Jack Cox said in an email that the company does not comment on rumors. Shire spokeswoman Gwen Fisher also said the company does not comment on rumors and speculation.
Wells Fargo analyst Brian Abrahams on Friday downgraded shares of ViroPharma to "market perform" and removed them from the bank's "priority stock list," citing the share price rise.
He said in a note to investors that ViroPharma could be a fit for larger companies seeking quality orphan assets, but believes the reward/risk profile of the shares is now better reflected in the higher valuation.
Reporting by Caroline Humer; Additional reporting by Deena Beasley in Los Angeles; Editing by Chris Reese