Richard C. Yocum

Bexarotene Is Effective and Safe for Treatment of Refractory Advanced-Stage Cutaneous T-Cell Lymphoma: Multinational Phase II-III Trial Results

PURPOSE Cutaneous T-cell lymphomas (CTCL) are malignancies of T cells appearing as skin lesions and are responsive to retinoid therapy. Safety and efficacy of a novel RXR-selective retinoid (rexinoid) bexarotene (Targretin, LGD1069; Ligand Pharmaceuticals Inc, San Diego, CA) was evaluated as a single-agent oral therapy administered once daily in an open-label study in patients with refractory advanced-stage CTCL. PATIENTS AND METHODS Ninety-four patients with biopsy-confirmed CTCL in advanced stages (IIB-IVB) were enrolled at 26 centers. Fifty-six patients received an initial dose of 300 mg/m2/d oral bexarotene and 38 started at more than 300 mg/m2/d. RESULTS Clinical complete and partial responses were reported by Primary End point Classification for the study in 45% (25 of 56) of patients enrolled at 300 mg/m2/d dosing. At more than 300 mg/m2/d, 55% (21 of 38) of patients responded, including 13% (five of 38) clinical complete. For the 300 mg/m2/d initial dose group, the rate of relapse after response was 36% and the projected median duration of response was 299 days. Improvements were also seen in overall body-surface area involvement, median index lesion surface area, adenopathy, cutaneous tumors, pruritus, and CTCL-specific quality of life. The most frequent drug-related adverse events included hypertriglyceridemia (associated rarely with pancreatitis), hypercholesterolemia, hypothyroidism, and headache. CONCLUSION Bexarotene is the first in a novel class of pharmacologic agents, the RXR-selective retinoids, or rexinoids. Bexarotene is orally administered, safe, and generally well tolerated with reversible side effects, and is effective for the treatment of advanced, refractory CTCL.

Multicenter Phase II Study of Oral Bexarotene for Patients With Metastatic Breast Cancer

PURPOSE Bexarotene is a retinoid X receptor-selective retinoid that has preclinical antitumor activity in breast cancer. We evaluated the efficacy and safety of oral bexarotene in the treatment of patients with metastatic breast cancer. PATIENTS AND METHODS The following three groups of patients were treated: hormone-refractory, chemotherapy-refractory, and tamoxifen-resistant patients. Patients in the first two groups were treated with bexarotene alone, whereas the tamoxifen-resistant patients received both tamoxifen and bexarotene. Patients in all groups were randomly assigned to receive bexarotene at either 200 or 500 mg/m(2)/d. RESULTS One hundred forty-eight patients were randomized; 145 patients were treated. Of 48 hormone-refractory patients, there were two partial responses (6%) and 10 patients with stable disease lasting more than 6 months; of 47 chemotherapy-refractory patients, there were two partial responses (6%) and five patients with stable disease; and of 51 tamoxifen-resistant patients, there was one partial response (3%) and 11 patients with stable disease. All partial responses occurred at the 200-mg/m(2)/d dose. The projected median time to progression across all of the arms was 8 to 10 weeks. There were no drug-related deaths, and only two patients had drug-related serious adverse events. The most common drug-related adverse events were hypertriglyceridemia (84%), dry skin (34%), asthenia (30%), and headache (27%). There were no cases of pancreatitis. CONCLUSION The efficacy of bexarotene in patients with refractory metastatic breast cancer is limited. However, it is an oral agent with minimal toxicity and a unique mechanism of action, which produced clinical benefit in approximately 20% of patients. Future efforts should define populations likely to benefit from this agent.

Topical bexarotene therapy for patients with refractory or persistent early-stage cutaneous T-cell lymphoma: results of the phase III clinical trial

OBJECTIVES We sought to determine the safety and efficacy of topical bexarotene (Targretin; Ligand Pharmaceuticals, La Jolla, Calif) gel 1% in patients with refractory or persistent early-stage cutaneous T-cell lymphoma. METHODS We conducted a multinational, open-label, phase III study of 50 patients with stage IA to IIA cutaneous T-cell lymphoma. The primary end point classification was the overall complete and partial response rate by the higher of 2 measures: the Physicians Global Assessment of Clinical Condition or the Composite Assessment of Index Lesion Disease Severity. RESULTS The overall response rates for the Physicians Global Assessment of Clinical Condition, Composite Assessment of Index Lesion Disease Severity, and primary end point classification were 44%, 46%, and 54%, respectively. The most common adverse events possibly related to study medication were mild to moderate irritant dermatitis, pruritus, pain (ie, primarily burning at application site), and skin disorder (eg, skin inflammation, excoriation, and new lesions). There were no serious treatment-related adverse events. CONCLUSIONS Topical bexarotene gel was generally well tolerated and demonstrated substantial efficacy in patients with refractory or persistent early-stage cutaneous T-cell lymphoma.