Study Compares Azathioprine, Mycophenolate Mofetil for Chronic Actinic Dermatitis

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Azathioprine and mycophenolate mofetil are effective and safe in the treatment of chronic actinic dermatitis, new findings suggest, though mysophenolate mofetil may lead to superior outcomes.¹

These conclusions were the result of new research led by Sanjeev Handa, from the department of dermatology, venereology and leprology at the Postgraduate Institute of Medical Education and Research in Chandigarh, India. The immunologically-mediated photodermatosis has, in uncontrolled studies, been treated efficaciously with azathioprine and with mycophenolate mofetil.²

“Despite the promising potential of both drugs, there is limited standardized data on their comparison,” Handa and colleagues wrote. “This RCT aimed to fill this gap by assessing effectiveness, adverse effects, quality of life impact, and treatment response factors in (chronic actinic dermatitis) patients treated with both drugs.”¹

Study Design

At the Postgraduate Institute of Medical Education and Research (PGIMER) in Chandigarh, India, the investigators carried out their prospective randomized controlled trial between January 2022 - December 2023. The study included subjects over the age of 18 years with chronic actinic dermatitis, specifically those who had been unresponsive to topical therapies.

In the research team’s initial assessment, they recorded subjects’ disease history, covering the disease's severity and duration, occupation, any history of atopy, average daily exposure to sunlight, and sunscreen implementation. The team evaluated the severity of chronic actinic dermatitis among participants using the Eczema Area and Severity Index (EASI), with the findings noted in a structured case record form.

Subjects also were assessed using the Dermatology Life Quality Index (DLQI) in either English or Hindi. The investigators’ conducted baseline examinations to determine eligibility, later randomly assigning them to 1 of 2 treatment cohorts of 25 individuals.

The research team gave Group A azathioprine, beginning at a dose of 50 mg once-per-day for 2 weeks and followed by an increase to 50 mg twice-per-day. The team treated Group B with mycophenolate mofetil, beginning at a 500 mg dose twice-per-day for 2 weeks and increasing to 1 g twice-per-day.

Concomitant topicals were allowed by the investigators, but the implementation of other immunosuppressants or anti-inflammatories were generally not allowed. They required a 4-week washout period for any prior systemic options, though a 1-week washout period was observed for previous topical steroids and tacrolimus use.

Their research took place over the course of 12 weeks, with follow-up assessments scheduled at the 2, 4, 8, and 12-week marks for all subjects. Subjects in both arms of the study were assessed using EASI in each follow-up interaction, and the DLQI was reassessed at the point of baseline and at the 12-week mark.

Follow-up laboratory tests were conducted by the investigators alongside their physical assessments, safety, and clinical photography at Weeks 2, 4, 8, and 12. They determined their primary aim would be to compare the proportion of individuals achieving a 75% EASI score reduction (EASI75) from baseline by the conclusion of the 12-week treatment period.

Findings

Overall, the investigators found that the median percentage EASI reduction at 12 weeks was far greater in Group B versus Group A. They reported that Group B had a reduction of 78.3% (IQR: 75.0–83.30%), adding that Group A had a 68.3% reduction (IQR: 31.2–80.10%; P = .034).

At first, the research team found that DLQI scores indicated moderate quality of life impact among both cohorts. They found by the 12-week mark that significant reductions in these scores appeared, though no significant differences were observed between either arm of the study at baseline (P = .291) or at the 12-week mark (P = .599).

A total of 23 of the participants were shown by the team to be non-responders, and these individuals tended to have illness durations which were longer (P = .026). They were also were more likely to report having outdoor occupations (P = .042), and both factors were linked with less favorable treatment responses.

The investigators found that the adverse effects they observed in their research were in line with known safety profiles. Despite this fact, a single subject had to stop taking azathioprine due to a hypersensitivity reaction.

“Moving forward, there is a pressing need for RCTs to compare the efficacy of these treatments, identify prognostic factors, and establish a treatment ladder for (chronic actinic dermatitis) management, addressing a crucial gap in the current understanding of the disease,” they wrote.

References

1. ^{Handa, S., Mehta, H., Bishnoi, A., Raj, D. and De, D. (2024), Efficacy and safety of azathioprine versus mycophenolate mofetil in chronic actinic dermatitis in skin of color: results of a randomized controlled trial. Int J Dermatol. https://doi.org/10.1111/ijd.17412.}
2. ^{Bär M, Schmitt J, Bauer A, Wozel G, Meurer M. Successful treatment of an elderly patient with refractory ultraviolet-A-sensitive atopic eczema with mycophenolic acid. Acta Derm Venereol. 2008; 88(4): 404–405.}