Recommendations for authors of manuscripts reporting inhibitor cases developed in previously treated patients with hemophilia: communication from the SSC of the ISTH

Summary Aim The scope of this recommendation is to provide guidance for reporting of inhibitor cases in previously treated patients ( PTP s) with hemophilia A. This guidance is intended to improve transparency and completeness of reporting of observed events; it does not cover planning, executing or analyzing original studies aimed at the assessment of inhibitor rates. Recommendation We recommend that for each case of inhibitor development reported in a published paper, a paragraph or a table is included in the main publication reporting as a minimum the underlined data fields in Table [Table 1. Data elements to be reported for inhibitor cases in PTPs]. We recommend transparent reporting when any of the suggested information is not available. We recommend that particular care is used in reporting the timeline of events by clearly identifying a reference time‐point. We suggest that journals in the field adopt this guidance as instructions for the authors and as a guide for reviewers. Conclusion Development of inhibitors in PTP s is a very rare event. Standardized reporting of inhibitor characteristics will contribute to generating a body of evidence otherwise not available. Case by case reporting of the recommended data elements may shed light on the natural history and risk factors of inhibitor development in PTP s and be useful for tailoring care in similar future cases.