Sima Sistani, who stepped down Friday, helped push WW International to embrace weight loss drugs.WeightWatchersWeightWatchers' CEO of roughly two years, Sima Sistani, is out.She helped push the company into the white-hot weight-loss drug space.Its interim chief said the company was in a critical period of transformation.It's been a bumpy year for WW International, the company also known as WeightWatchers.In a leadership shake-up Friday, the weight-loss company announced CEO Sima Sistani is stepping down after roughly two years — effective immediately — and board member Tara Comonte is stepping up to serve as interim chief."On behalf of the Board, I want to sincerely thank Sima for her leadership in advancing our strategy, for adding WeightWatchers Clinic to our offerings, and for her unwavering commitment to our mission," said Thilo Semmelbauer, Chairman of the WeightWatchers Board of Directors.