Thalidomide maintenance following high-dose therapy in multiple myeloma: a UK myeloma forum phase 2 study.

Thalidomide maintenance has unresolved issues regarding dosage and toxicity. We evaluated this in five dose cohorts in 100 patients. At a median follow-up of 32.3 months, 23 patients had stopped thalidomide for disease progression, 54 for side effects. 3-year overall and progression-free survival was 76% and 41% respectively. Dosage did not influence disease outcome but greatly affected toxicity. Fifteen patients converted from partial remission to complete remission on thalidomide at a median of 13.5 months. Maintenance doses >200 mg were largely unachievable and peripheral neuropathy was the main toxicity. Lower doses enabled more patients to stay on the drug for a useful period of time.