By James Hibberd
Updated April 28, 2011 at 06:41 PM EDT
Credit: Stephen Shugerman/Getty Images

It’s official: The CW’s entertainment president since its inception, Dawn Ostroff, will step down next month and will be replaced by former ABC Studios chief Mark Pedowitz, who helped develop hits like Lost, Desperate Housewives, Grey’s Anatomy, Ugly Betty, Scrubs, Army Wives, Ghost Whisperer and Criminal Minds.

The CW launched five years ago after The WB and UPN merged and has struggled to gain ratings traction at a time when broadcast in general has slipped. Though shows like Gossip Girl and The Vampire Diaries have broken through, most of the network’s top draws are aging hits that The CW inherited — like Smallville, One Tree Hill and America’s Next Top Model. Meanwhile, cable rivals going after the network’s young female viewers, like MTV and ABC Family, have proven formidable competitors, with shows like Secret Life of the American Teenager, Jersey Shore, and Teen Mom pulling serious numbers.

The network has seemed to have a tough time figuring itself out — is it the female soap network? The supernatural genre network? And then there’s Top Model, its only reality hit. Its target demo clearly loves reality shows — just look at MTV — but the network has never found another show that it was able to successfully pair with Top Model on Wednesday nights.

Next fall’s crop of CW pilots are already being shot, so turning around The CW might take awhile, even if Pedowitz hits the ground running…