On which evidence can we rely when prescribing off-label methotrexate in dermatological practice? – a systematic review with GRADE approach

If an authorized drug is prescribed for a use that is not described in the Summary of Product Characteristics, this is defined as ‘off-label use.’ Methotrexate is often used off-label for dermatological indications. Off-label use is permitted if physicians can justify the treatment based on scientific evidence available to them. Our objective here was therefore to summarize the evidence for the effectiveness, efficacy, and safety of the dermatological off-label use of methotrexate in a systematic review. We searched MEDLINE, EMBASE, and CENTRAL for studies for evidence on the effectiveness, efficacy, and safety of the off-label use of methotrexate in dermatological indications up to November 2019. We used the GRADE system to rate the quality of the evidence. The search retrieved 34,583 hits of which 3566 were selected after the title and abstract screening. After the full-text screening, 143 studies were included, which involved 3688 patients in total. We found low-quality evidence for the effectiveness, efficacy, and safety of the off-label use of methotrexate in 31 dermatological diseases. To optimize the quality of evidence to support off-label use, we need high-quality studies in which well-characterized patients are treated with standardized treatments regimens using well-validated outcomes relevant to patients and physicians.