International Consensus Reached on Methotrexate Dosing for Psoriasis

NEW YORK (Reuters Health) – Dermatologists worldwide reached consensus on 20 of 21 proposals involving methotrexate (MTX) dosing in patients with psoriasis, with the intent of harmonizing treatment across global psoriasis patient populations.

“The variability in treatment regimens might contribute to suboptimal treatment with MTX or can lead to early discontinuation of treatment due to limited efficacy or side effects,” Dr. Astrid van Huizen of the University of Amsterdam told Reuters Health by email. “With the publication of this consensus study, we hope to raise awareness on the different MTX dosages used in daily practice and the need for a more uniform dosing regimen.”

“We discussed many aspects of MTX dosing in this consensus study,” she added, “including test dose, start dose, the increase or decrease of the dose, administration form, maximum dose, administration and the use of folic acid specified for specific populations – adults, children and vulnerable patients.”

As reported in JAMA Dermatology, Amsterdam University developed and distributed an online survey between September 2020 and March 2021. The survey included 180 participants worldwide (30.6% in non-Western countries). Participants worked mainly at university hospitals (53.9%) and were experienced in treating psoriasis patients with methotrexate; 91.6% had more than 10 years of experience.

The survey was conducted in three rounds. Proposals on which no consensus was reached were discussed in a conference meeting.

Participants voted on 21 proposals with a 9-point scale (1-3 disagree, 4-6 neither agree nor disagree, 7-9 agree). Consensus was defined as less than 15% voting disagree (1-3). For the consensus meeting, consensus was defined as less than 30% voting disagree.

All 180 participants completed the three survey rounds, and 58 (23.1%) joined the conference meeting. Consensus was achieved on 11 proposals in round 1, three proposals in round 2, and two proposals in round 3. In the consensus meeting, consensus was achieved on four proposals.

Dr. van Huizen summarized the key dosing regimen proposals for Reuters Health:

– No test dose of MTX is needed in adults, children or vulnerable patients.

– MTX can be started with 15 mg/week in adults and 7.5 – 10 mg/week in vulnerable patients.

– In children, dosing should be based on square meter.

– Folic acid should be supplemented once a week, 24 hours after MTX intake.

“No consensus was reached on whether the dosage of folic acid should be increased when increasing the dosage of MTX,” she said. “Furthermore, the evidence for the use of folic acid is controversial and dosing regimens strongly depend on availability.”

“It is challenging to define a vulnerable population,” she added. “We discussed elderly patients or patients with an impaired kidney function in our study group. In future research, we need to define which subpopulation needs a specific dosing schedule.”

The authors write in the paper, “This consensus may help clinicians to optimize treatment for patients with psoriasis with MTX worldwide because MTX is an important drug, being affordable and globally accessible. This consensus can be used in current practice and guidelines. The identified knowledge gaps can potentially be the basis for future research.”

Dr. John Barbieri, Director, Advanced Acne Therapeutics Clinic at Brigham and Women’s Hospital in Boston commented by email, “I think their findings largely coincide with current practice. I think there is a need for additional research on optimal lab monitoring practices for MTX, including how to monitor for the development of chronic hepatotoxicity.”

SOURCE: https://bit.ly/3v3I2RS JAMA Dermatology, online March 30, 2022.

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