Retinoic acid receptor agonist as monotherapy for early-stage mycosis fungoides: does it work?

Abstract

Background: Retinoids exert their biologic effects by binding to intracellular retinoic-acid receptors (RARs) and/or retinoid X receptors (RXRs). Early-stage mycosis fungoides (MF) has been effectively treated with bexarotene, an RXR-agonist, with overall response (OR) rates 54–67% and complete response (CR) rates 7–27%. Data on RAR-agonist monotherapy are limited.

Objective: To analyze the effectiveness of RAR-agonist monotherapy for early-stage MF.

Methods: Data on patients with early-stage MF treated with acitretin/isotretinoin monotherapy at a tertiary cutaneous lymphoma clinic in 2010–2017 were collected retrospectively from the medical files.

Results: Thirty-five patients (26 males) of median age 50 years (range 8–83) with early-stage MF (IA 9, IB 26) underwent 37 treatment events: 25 acitretin and 12 isotretinoin at a median dosages of 0.3 mg/kg (range 0.2–0.9) and 0.2 mg/kg (range 0.1–0.7), respectively. Median time to maximal response was 6 months for both (range 1–10 for acitretin, 3–16 for isotretinoin); median treatment duration was 10 months (range 3–46) for acitretin, and 9 months (range 3–55) for isotretinoin. OR was 64% for acitretin and 80% for isotretinoin, and CR, 4% and 8%, respectively. Side-effect profiles were as previously reported for retinoids.

Conclusions: Early-stage MF patients may benefit from low dose RAR-agonist monotherapy, although the CR rate is low.

Keywords:

• Acitretin
• early-stage mycosis fungoides
• isotretinoin
• RAR
• retinoic acid receptor
• retinoids

Disclosure statement

The authors have no conflicts of interest to declare.