Endocrine Abstracts

Background and aims: Bexarotene is the first retinoid receptor X (RXR)-selective agonist approved for cutaneous T-cell lymphoma in patients resistant to at least one previus systemic treatment. However, it produces often two endocrine-metabolic alterations: central hypothyroidism and dyslipidemia. We assessed, in a group of patients with Mycosis Fungoide or Sezary syndrome treated with bexarotene, the endocrine-metabolic side effects.

Patients and methods: Descriptive and retrospective study of 13 patients (4 women) treated with bexarotene (300 mg/m²) in the department of Dermatology of our Hospital between 2003 and June of 2006 by Mycosis fungoide or Sezary syndrome. We analyzed the clinical characteristics of the patients, the efficacy of the treatment and the endocrine-metabolic side effects relationated with the drug.

Results: Patients assessed were 59,53 years old (28–79). Median period of treatment was 11,3 months but 4 patients were continuing at the end of the period of the study. 3/13 patients (23,1%) achieved partial remission, 4/13 (30.8%) achieved complete remission, 4/13 (30.8%) were stable and 2/13 (15.5%) progressed. 3/13 cases (23.1%) were treated with oral bexarotene as monotherapy and 10/13 (76.9%) in combination with other active agents (included topic steroids).

The most frequent side effects were hypertriglyceridemia in 13/13 (100%), hypercholesterolemia in 12/13 (92.3%) and central hypothyroidism in 7/13 (53.8%). Thyroid hormone replacement therapy and additional treatment with statin or fenofibrate was used in these cases. In patients who discontinued bexarotene treatment, thyroid function and lipid levels returned to baseline values.

Conclusions: Bexarotene is an effective therapeutic option in patients with cutaneous T-cell lymphoma but usually it produces central hypothyroidism and dyslipidemia which require treatment with levothyroxine and lipid-lowering agents. These frequent alterations must be in mind when bexarotene treatment is prescribed.