Health Winners & Losers: Tercica

Updated from 2:07 p.m. EDT with new stock prices

Biotech stocks followed the broader markets Thursday amid a flurry of business news and analyst actions.

Shares of Tercica (TRCA Quote) surged on news Ipsen, a French specialty drug company that owns 25% of the biopharmaceutical company, will buy all of the Tercica shares that it doesn't already own for $9 a share in cash. The deal values Tercica at $663 million. The price is a 104% premium to Tercica's closing price on Thursday.

Ipsen and its affiliates currently own roughly 25.3% of the company and agreed to immediately exercise its outstanding Tercica warrant and convert outstanding convertible notes, after which it will own around 42.7% of Tercica's outstanding stock.

Tercica shares jumped $4.39, or 99.6%, to $8.80.

Other stocks moved on analyst actions: Cowen and Co. upgraded Vertex (VRTX Quote) to outperform from neutral. Analyst Rachel McMinn said in a note to investors that she believes Vertex may disclose top-line interim results from the PROVE 3 trial in the coming weeks in conjunction with a release about phase III trial design in patients with hepatitis C who have tried other treatments unsuccessfully . Based on the prospective strength of teleprevir 3-times-daily and 2-times-daily data, McMinn upped her peak sales estimate for telaprevir to $3 billion from $2.4 billion and accelerated her expectation for the drug's launch to 2010 from 2011.

Vertex shares climbed $3.72, or 12.9%, to $32.57.

Also Thursday, Credit Suisse analyst Michael Aberman downgraded Regeneron (REGN Quote) to neutral from outperform and lowered its price target to $24 from $30. Aberman wrote in a note to investors that after attending the annual meeting of the American Society of Clinical Oncology this year, his team came away with a more cautious view on Regeneron's aflibercept based on its potential to result in more toxicity than Genentech's (DNA Quote) Avastin. Regeneron's shares were down $3.79, or 19.9%, at $15.29. Genentech shares were up 58 cents, or 0.8%, at $73.05.