An FDA complete response letter (CRL) for the experimental familial chylomicronemia syndrome (FCS) drug Waylivra (volanesorsen) left the team at Ionis Pharmaceuticals Inc. subsidiary Akcea Therapeutics Inc. disappointed and possibly surprised following a qualified endorsement of the candidate by an agency advisory committee last spring. Akcea relayed nothing about the agency's reasons for the response, but concerns over the drug's safety, clinical benefit and trial population arose in the adcom meeting last May.