Bexarotene (Targretin) is a retinoid analogue that selectively binds and activates retinoid X receptor (RXR) subtypes. In the context of lymphoma management, it is primarily utilized for Cutaneous T-cell lymphoma (CTCL), specifically Mycosis Fungoides (MF) and Sezary Syndrome (SS).
I. Indications and Usage in CTCL
- Topical Therapy: Bexarotene is used as a topical retinoid for localized skin involvement (Stage IA) to improve symptoms and quality of life while avoiding systemic toxicities.
- Systemic Therapy: It is a Category A preferred systemic regimen for various stages of MF/SS, including Stage IB–IV and Sezary Syndrome.
- Place in Therapy: It can be administered as a single agent or in combination with skin-directed therapies like phototherapy. Clinical response rates are approximately 50%.
II. Dosing and Administration
- Oral Dose: The standard systemic dose is 300–400 mg/m² PO daily.
- Duration: Treatment is often continued indefinitely until the disease progresses or the side effects become intolerable, as clinical responses in CTCL are rarely durable.
III. Pharmacist Monitoring and Toxicities
Bexarotene has a unique and predictable side effect profile that requires proactive management by the oncology pharmacist:
- Hyperlipidemia: This is a very common and significant side effect.
- Monitoring: Obtain a baseline lipid panel before starting therapy and monitor periodically thereafter.
- Hypothyroidism: Specifically, it causes central hypothyroidism.
- Monitoring: Obtain baseline TSH and thyroid panels prior to initiation and monitor during treatment.
- Alternatives: If bexarotene is not tolerated or available, other systemic retinoids such as acitretin or isotretinoin may be considered.
Synonyms
Targretin