Acelyrin Inc. said a vendor used by Fortrea Inc., a CRO the company used for its phase IIb/III study testing interleukin-17A inhibitor izokibep in psoriatic arthritis, incorrectly programmed the study’s protocol and created a dose sequencing error, resulting in some patients in two of the four dosing arms to randomly receive placebo and active treatment instead of the intended alternating pattern. The discovery has prompted a review of other studies involving the CRO, including a study that failed to reach statistical significance in September.