Prothena Corp. plc is quitting development of its most advanced candidate, NEOD-001 for AL amyloidosis, after a phase IIb failure triggered a review of the program's phase III study, leading to its discontinuation for futility. The phase IIb study, Pronto, missed both its primary and secondary endpoints, while an independent data monitoring committee (DMC) recommended discontinuation of the phase III trial, called Vital.