Treatment of Waldenstrom's macroglobulinemia with clarithromycin, low-dose thalidomide, and dexamethasone.
Twelve patients with Waldenstrom's macroglobulinemia (WM) underwent treatment with the nonmyelosuppressive combination regimen BLT-D: clarithomycin (Biaxin [BXN], Abbott Laboratories, Abbott Park, IL) 500 mg orally twice daily, low-dose thalidomide (THAL) 50 mg orally escalated to 200 mg daily, and dexamethasone (DXM) 40 mg orally once weekly all with modification for toxicity. Omeprazole (correction of omepraxole) 20 mgm orally twice daily for 2 days with the DXM, and enteric-coated aspirin 81 mg orally daily were also administered. Twelve patients have been evaluated. All had previously received at least one purine analogue or alkylating agent. Five had a reduction in either leukocytes and/or platelets prior to treatment, of which three were disease-related. Median age was 62 years. All patients received a minimum of 6 weeks of therapy. Of the 12 patients, 10 had a significant response (83%) consisting of three near complete, three major, four partial, and two minor responses. Four of five had restoration of reduced blood counts. Two with minor responses did not receive sufficient dose escalation due to toxicity. Median time on therapy was 7 months (range, 3 to 28 months). Patients were removed from therapy primarily due to neurotoxicity. Drug resistance occurred in three patients, with one transformation to large cell lymphoma. Toxicity was as follows: gastrointestinal (primarily constipation), 42%; neurological, 100%; endocrine, 42%, and thrombotic, 8%. Most toxicities were World Health Organization (WHO) grade 1 or 2; however, neurological toxicity was more prominent and severe in WM patients than in myeloma. BLT-D is effective in WM. Because of its toxicity, predominantly neurological, BLT-D may best serve as an induction regimen or to "rescue" patients with refractory disease or disease-related low counts.