Trimetrexate in relapsed T-cell lymphoma with skin involvement

Methotrexate (MTX) is active against lymphomas, but transport or polyglutamylation mutations confer MTX resistance. Because trimetrexate (TMTX) enters cells by passive diffusion and is not polyglutamylated, its activity in relapsed T-cell lymphoma was investigated.

Eligible patients had histologically confirmed relapsed T-cell lymphoma involving the skin, had received more than one previous regimen, were older than 16 years, had normal organ function, and had no CNS disease or serious infections, including human immunodeficiency virus. TMTX (200 mg/m(2)) was given intravenously every 14 days without topical or systemic corticosteroids. Patients who responded received up to 12 doses.

Twenty patients were assessable for response. Median age was 59 years (range, 45 to 87 years); 13 patients were men. Three patients had anaplastic large-cell lymphoma, 15 had mycosis fungoides or Sézary syndrome (14 with large-cell transformation), and two had peripheral T-cell lymphoma. Serum lactate dehydrogenase was high in 35%, and beta-2 microglobulin was more than 3.0 mg/L in 35% of patients. The median number of previous regimens was three (range, two to 15) and included MTX in five patients. Disease was refractory to the regimen immediately preceding TMTX in 85% of patients. Responses were complete in one and partial in eight patients (overall response rate, 45%). Two of five patients previously treated with MTX responded. Grade 3 or 4 mucositis was observed after 4%, infection after 3%, neutropenic fever after 6%, neutrophils less than 100/microL after 4%, and platelets less than 10,000/microL after 3% of TMTX doses.

TMTX is active with acceptable toxicity in this population and merits further investigation.