Bexarotene gel was evaluated for the treatment of patients with early stage (Stage IA-IIA) CTCL in one multicenter, open-label, clinical trial as well as in a Phase I-II program (dose-seeking trials with different response criteria than the multicenter trial). These clinical studies enrolled a total of 117 patients.

In the multicenter, open-label clinical trial, Bexarotene gel was evaluated for the treatment of patients with early stage CTCL who were refractory to, intolerant to, or reached a response plateau for at least six months on at least two prior therapies. The study was conducted in the U.S., Canada, Europe, and Australia and enrolled a total of 50 patients; 46% of these patients were male, 80% were Caucasian, and the median age was 64 years (range 13 to 85).

Bexarotene gel was also evaluated for the treatment of patients with CTCL in a U.S. Phase I-II program involving patients with early stage CTCL. This program enrolled a total of 67 patients; 55% of these patients were male, 85% were Caucasian, and the median age was 61 years (range 30 to 87).

In the multicenter, open-label clinical trial, considering prior systemic, irradiation, and topical treatments, patients had been exposed to a median of three prior therapies (range 2-7). All patients failed at least two treatments; the majority (68%) of patients were either refractory to two or more therapies or were refractory to one therapy and intolerant to at least one therapy.

Patients were treated with Bexarotene gel 1% for a planned 16-week period with an option to continue provided that no unacceptable toxicity was occurring.

Tumor response was assessed in the multicenter study by observation of up to five baseline-defined index lesions using a Composite Assessment of Index Lesion Disease Severity (CA). This endpoint was based on a summation of the grades, for all index lesions, of erythema, scaling, plaque elevation, hypopigmentation or hyperpigmentation, and area of involvement. New cutaneous lesions or tumors and extracutaneous disease manifestations were not considered in response or disease progression assessments.

All tumor responses required confirmation over at least two assessments separated by at least four weeks. A partial response was defined as an improvement of at least 50% in the index lesions. A complete clinical response required complete disappearance of the index lesions, but did not require confirmation by biopsy.

Bexarotene gel produced an overall response rate of 26% (13/50) with a corresponding exact 95% confidence interval from 14.6% to 40.3% by the Composite Assessment of Index Lesion Severity. For the Stage IA and IB patients, the response rate was 28% (13/47) with a corresponding exact 95% confidence interval from 15.6% to 42.6%. For the Stage II patients the response rate was 0% (0/3). Two percent of patients (1/50) had a clinical complete response. The median time to best response on the Composite Assessment of Index Lesion Severity (n=13) was 85 days (range: 36-154).

The rate of relapse in responding patients by the Composite Assessment of Index Lesion Severity was 23% (3/13) over a median observation period of 149 days (range 56-342). Fourteen patients developed new lesions in untreated areas (14/50; 28%). Four patients developed clinically abnormal lymph nodes (≥1 cm diam) (4/50; 8%). One patient developed a cutaneous tumor (1/50; 2%).

The Phase I-II program (dose-seeking trials with different response criteria than the multicenter trial) was supportive of the multicenter study results.