* Stops developing eplivanserin in insomnia
* Also discontinues thrombosis drug idrabiotaparinux
* Fast track U.S. approval process for prostate cancer drug
* Shares fall 1 percent (Rewrites, adds analyst comment and shares)
PARIS, Dec 21 (Reuters) - French drugmaker Sanofi-Aventis (SASY.PA) stopped developing two medicines as part of an overhaul of its research and development portfolio, saying they would not bring significant benefits.
U.S. regulators have, however, granted a speedier approval process for Sanofi's cabazitaxel as a second-line treatment for prostate cancer, the group said on Monday.
"Sanofi-Aventis is doing what it should be doing -- going through the R&D pipeline and dropping unprofitable and non-promising projects," said Kepler Capital Markets analyst Tero Weckroth.
The French company's third-quarter earnings beat forecasts but it is still in dire need of new blockbuster medicines that can help compensate for sales losses of older drugs due to generic competition and to new branded rivals. [ID:nSP443666]
Sanofi abandoned its insomnia drug eplivanserin, citing regulatory requirements for more clinical data and market access constraints
Peak sales of the drug could have hit 220 million euros ($315 million), according to Weckroth. Rival Actelion (ATLN.VX) also said on Monday there were unspecified safety problems in a trial of its own sleep drug. [ID:nGEE5B21B6] But adding cancer drug cabazitaxel forecasts should at least compensate for lost potential sales of eplivanserin, Weckroth added.
Sanofi also halted development of thrombosis treatment idrabiotaparinux in atrial fibrillation, saying there was too little benefit to patients.
Its shares fell 1.0 percent to 54.16 euros by 1122 GMT, just behind a 0.5 percent drop in the DJ Stoxx European healthcare index .SXDP.
"Stopping these drugs is not a surprise," said Eric Le Berrigaud, analyst at Raymond James. "Chris Viehbacher, the chief executive of Sanofi, had declared himself a pessimist on these two drugs that have been stopped today." (Reporting by Sudip Kar-Gupta and Noelle Mennella; writing by Sam Cage; Editing by Jon Loades-Carter) ($1=.6978 Euro)