Selective CD4+ Lymphopenia in Melanoma Patients Treated With Temozolomide: A Toxicity With Therapeutic Implications

Purpose Standard schedule temozolomide (TMZ; daily for 5 days every 4 weeks) is often used in melanoma patients, but phase III data show that it is no more effective than standard dacarbazine. Extended TMZ dosing regimens may be superior by delivering the drug continuously at a higher dose over time. Using an extended dosing schedule, we noted a high incidence of lymphopenia and occasional opportunistic infections (OIs). Here we report our retrospective experience in the first 97 patients. Materials and Methods TMZ was administered at 75 mg/m2/d orally for 6 weeks every 8 weeks, although nine patients were treated continuously without a break. Seventeen patients were treated with TMZ alone; 73 patients received TMZ with thalidomide; seven patients received TMZ with low-dose interferon alfa. Results Median duration of TMZ treatment was 113 days; 29% received ≥ 24 weeks of therapy. Lymphopenia was seen in 60% of patients (absolute lymphocyte count < 800/μL) with a median of 101 days to lymphopenia. TMZ did ...