** Shares of drug developer Fulcrum Therapeutics FULC.O fall 49.7% to $3.23 premarket

** Co said late on Monday it is discontinuing development of its experimental pociredir program for the treatment of sickle cell disease, an inherited blood disorder

** Fulcrum said that FDA had expressed concerns tied to secondary blood cancers seen with Ipsen's IPN.PA cancer drug, Tazverik, which was withdrawn globally in March

** The company said it submitted information to the FDA supporting the position that mechanistic differences between the two drugs' target were relevant to the benefit-risk assessment

** The FDA, however, concluded that any drug that targets the protein PRC2 carries risk

** Fulcrum will explore options including a merger, acquisition, business combination or other transaction, and has initiated efforts to cut operating expenses and preserve cash

** Up to last close, stock down 43% YTD