Weekly azathioprine pulse efficacious in psoriasis: study

In this randomized controlled trial, 80 patients with chronic plaque psoriasis who had persistent disease for more than 6 months, psoriasis area severity index (PASI) >10 and body surface area (BSA) more >10% were enrolled. After detailed clinical and laboratory evaluation, patients were randomized to 2 groups to receive either weekly 300 mg azathioprine (n = 40) or 15 mg methotrexate every week (n = 40) for 20 weeks or PASI 100 improvement whichever is earlier, following which the response to treatment and adverse effects were assessed.

Pre‑treatment and post‑treatment clinical photographs of the affected sites were taken. Clinical and biochemical assessments were done at baseline and then every 4 weeks. Patients were followed up at week 2 and 4, and then every 4 weeks by a single blinded observer. Follow up was done for a period of 3 months following treatment completion to determine any relapse. Relapse was defined as loss of 50% or more of PASI improvement from the baseline who has achieved a significant clinical response.

Results

Overall 48 (60%) patients achieved PASI 75 response- 17 (35.4%) patients in azathioprine group and 31 (64.9%) in methotrexate group

36 (45%) patients achieved PASI 100 response - 14 (38.9%) patients in azathioprine group 1 and 22 (61.1%) in methotrexate group

59 (73.8%) patients achieved PASI 50 response- 22 (37.3%) patients in azathioprine group 1 and 37 (62.7%) in methotrexate group

On intention to treat analysis, PASI ≥ 75 was achieved in 47.5% (19/40) patients in azathioprine group compared to 85% (34/40) patients in methotrexate group (p < 0.001)

On per protocol analysis, PASI ≥ 75 was achieved in 86% (19/22) patients in azathioprine group and 92% (34/37) patients in methotrexate group (p = 0.497)

Mean PASI at 20 weeks was 1.9 (0‑9.9) in azathioprine group while it was 0.89 (0‑5.8) in methotrexate group.

Minor clinical and biochemical adverse effects were noted in both the groups, which were comparable.

7 patients in azathioprine group and 3 patients in methotrexate group stopped the treatment

One (7.7%) patient in azathioprine group and 4 (17.4%) in methotrexate group relapsed during follow‑up.

Methotrexate remains the most frequently used drug in the treatment of psoriasis despite availability of several therapeutic agents. Azathioprine, a potent T cell inhibitor, has been sparingly used in this disease. On per protocol analysis, PASI 75 achievement was comparable in azathioprine and methotrexate groups (p = 0.497). The high dropout in azathioprine group was attributed to its slow rate of response compared to methotrexate.

In conclusion weekly azathioprine pulse appears to be beneficial in the management of chronic plaque psoriasis though less effective than weekly methotrexate. Weekly azathioprine pulse thus can be a suitable treatment option in psoriasis patients with contraindication to methotrexate or other similar agents.

Source- Verma KK, Kumar P, Bhari N, Gupta S, Kalaivani M. Azathioprine weekly pulse versus methotrexate for the treatment of chronic plaque psoriasis: A randomized controlled trial. Indian J Dermatol Venereol Leprol 2021;87:509-14