Experience with 9-cis retinoic acid in patients with relapsed and refractory non-Hodgkin's lymphoma

We conducted a phase II study to determine the efficacy and toxicity of 9-c is-retinoic acid (9-cis RA), a pan-retinoid receptor agonist. in the treatm ent of patients with relapsed and refractory NHL, Patients were eligible if they had histologically documented relapsed refractory T cell or indolent B cell NHL. The first three patients enrolled received 70 mg/m(2) of 9-cis RA orally twice a day, but the remaining patients received a single oral da ily dose of 100 mg/m(2). After 6 weeks of therapy, tumor response was asses sed objectively. Response rate and toxicity were determined in all 29 eligi ble patients based on an intent-to-treat analysis. Four patients (14%) resp onded (3 PRs and 1 CR; 95% CI 4%- 33%). One patient had a minor response, a nd eight had stable disease. Responses were observed in two (11%) of 19 pat ients with B-cell lymphoma and in two (20%) of 10 patients with T-cell lymp homa. The median time-to-treatment failure for the 29 eligible patients was 8 weeks. The most frequent toxic effects were dry skin. headache, hypertri glyceridemia and hypercalcemia. Five patients discontinued therapy due to t oxic side effects, but no toxic deaths occurred during the study. We conclu de that 9-cis RA has a modest activity in relapsed and refractory NHL. In t his study, responses were observed in patients with B-cell lymphomas and th ose with T-cell lymphomas.