Conflict of interest

The following authors served as clinical investigators for one or more studies, including this trial, sponsored by Ultragenyx Pharmaceutical Inc. in partnership with Kyowa Kirin International plc: MLB, SJdB, KB, TOC, HIC, MC-S, RKC, RE, YI, EAI, KI, SI, NI, MKJ, PK, RK, TK, RHL, FP, PP, AAP, SHR, HT, TJW, H-WY, YT. SJdB, TOC, EAI, RHL, FP, AAP, and TJW have also received honoraria from Ultragenyx Pharmaceutical Inc. for serving as an advisory board member or for delivering lectures and AAP and TJW have received travel reimbursement. TOC, YI, MJK, RK, TK, and YT have received honoraria for serving as an advisory board member or for speaker fees from Kyowa Kirin International plc. During the past 3 years, the following authors have received grants outside of the submitted work: RE from Alexion Pharmaceuticals, Amgen, Immunodiagnostic Systems Holdings plc, Nittobo Medical Co., Ltd., and Roche; SI from Alexion Pharmaceuticals, Radius Health, and Takeda Pharmaceutical Company; NI, MJK, and RHL from Kyowa Kirin International plc; TK from Teijin Pharma; PP from Ultragenyx Pharmaceutical Inc.; and SHR from Amgen, UCB, and AstraZeneca. PP is currently an employee of Ascendis Pharma Inc. AW is an employee of Kyowa Kirin International plc and WS is an employee of Kyowa Kirin Pharmaceutical Development, Inc. AN and MN are employees of Chilli Consultancy and have received consultancy fees from Kyowa Kirin International plc to support the development of this manuscript and for projects outside this submitted work.

Human and Animal Rights and Informed Consent statements

As stated in the abstract, this study is a post hoc subgroup analysis from an approved phase 3 Clinical Trial (ClinicalTrials.gov NCT02526160) for which informed consent was obtained from all participants in the study.