Which Antipsoriatic Drug Has the Fastest Onset of Action?: Systematic Review on the Rapidity of the Onset of Action

The time necessary for a treatment to become effective is crucial for patients and physicians but has been largely neglected in the reporting and comparison of clinical trials in dermatology. The aim of this systematic review is to determine the time until the onset of action (TOA) of systemic agents approved for moderate-to-severe psoriasis. Primary outcome is the TOA defined as the weighted mean time until 25% of the patients achieved a psoriasis area and severity index (PASI) 75 response. Among the biologics, infliximab has the shortest TOA (3.5 weeks), followed by ustekinumab (high dose 4.6/low dose 5.1 weeks/not weight adapted), adalimumab (4.6 weeks), etanercept (high dose 6.6/low dose 9.5 weeks), and alefacept (high dose 15.4 weeks/low dose: no data). Among the conventional treatments, good data are available for cyclosporine A (CsA; TOA: 6.0 weeks) and limited data are found for methotrexate (MTX; TOA: high dose 3.2/low dose 9.9 weeks). No data are available for fumaric acid esters and retinoids. This systematic review provides clinically relevant information on the onset of action of antipsoriatic agents, although the data currently available allow only a limited assessment. Psoriasis trials should consider including TOA as an additional outcome measure.