Clinical Utility Of Genetic Screening For HLA-B*1301, On Susceptibility To Dapsone Hypersensitivity Syndrome

This Study is to evaluate the utility of prospective HLA-B\*1301 screening on the incidence of dapsone hypersensitivity syndrome (DHS) in 3130 previously Dapsone(DDS)-naive patients. Those patients include allergic cutaneous vasculitis, urticaria, psoriasis, acne, bullous skin diseases, sterile pustulosis, leprosy, pneumocystis pneumonia and any other patients who need dapsone administration. The study has two (co-primary) objectives: i) to determine if screening for HLA-B\*1301 prior to DDS-containing treatment results in a lower incidence of clinically-suspected DHS versus current standard of care (no genetic screening) and ii) to determine if screening for HLA-B\*1301 prior to DDS-containing treatment results in a significantly lower incidence of immunologically-confirmed DHS versus current standard of care (no genetic screening or patch testing). The study consists of up to a 5-day screening period, a randomised observation period (Day 1 through Week 6) and, for subjects experiencing a suspected DHS and a subset of DDS-tolerant subjects, an epicutaneous patch test (EPT) assessment period. Eligible subjects will be randomised to one of two study arms: a Current Standard of Care Arm (no prospective genetic screening: Control) and a Genetic Screening Arm (prospective genetic screening: Case). Subjects identified as HLA-B\*1301 positive in the prospective Genetic Screening Arm will not receive dapsone and will be excluded from further study. Subjects who experience suspected DHS during the 6-week observation would be withdrawn from dapsone and undergo EPT patch testing 6 weeks later.