Taking 15 mg per week of methotrexate over 9 months with targeted dosage escalation can lead to significant improvements in skin, dactylitis, enthesitis, joint, and functional domains of psoriatic arthritis (PsA), according to a study published in Rheumatology.

Researchers of this open-label, prospective study of patients with psoriatic arthritis evaluated and documented the efficacy of methotrexate, which had been shown to have limited efficacy in previously published, randomized, controlled studies. Participants received 15 mg per week doses of methotrexate over a 9-month follow-up period.

Measurements of disease activity were assessed by physician and patient global assessment, tender and swollen joint count, Minimal Disease Activity, 28-joint count disease activity score based on erythrocyte sedimentation rate (DAS28-ESR), Leeds Enthesitis Index (LEI), Leeds Dactylitis Instrument basic, Clinical Disease Activity Index for PsA (cDAPSA), Health Assessment Questionnaire (HAQ), and Psoriasis Area and Severity Index (PASI) at baseline and 3, 6, and 9 months. Response to methotrexate was assessed by cDAPSA response, European League Against Rheumatism (EULALR) DAS28-ESR , HAQ response, and Psoriasis Area and Severity Index (PASI75). Disease activity dictated escalations in dosage and use of combination disease-modifying antirheumatic drugs (DMARDS).  

Out of a total 73 participants (mean age, 44 years), only 7 received additional DMARDS, and the mean methotrexate dose used was 17.5 mg per week. After 9 months of treatment, 58.0% of participants experienced significant improvements (<.05) in swollen joint count, tender joint count, global activity, cDAPSA, DAS-28ESR, LEI, Leeds Dactylitis Index basic, HAQ, and PASI. A total of 58.9% of patients achieved major cDAPSA response, and moderate and good EULAR DAS28 response was seen in 74% and 6.8% of participants, respectively. An HAQ response was seen in 65.8% of participants, a PAS175 response was seen in 67.9%, and 63% of participants achieved Minimal Disease Activity.

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Study investigators conclude that “baseline [methotrexate] of >15mg/ week, with targeted escalation every 4-12 weeks, resulted in significant sustained improvement in the skin, joint, dactylitis, enthesitis and functional domains of psoriasis. This effect size demonstrated that using current validated instruments will provide the required data for [methotrexate] efficacy for trials that test newer drugs in PsA.”

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Reference

Appani SK, Devarasetti PK, Irlapati RVP, Rajasekhar L. Methotrexate achieves major cDAPSA response, and improvement in dactylitis and functional status in psoriatic arthritis [published online December 24, 2018]. Rheumatology (Oxford). doi:10.1093/rheumatology/key369