Lenalidomide gained Food and Drug Administration (FDA) approval for treatment of patients with relapsed or refractory multiple myeloma (MM) in combination with dexamethasone in June 2006. In April 2005, the FDA and patient advocacy groups requested an expanded access programme to both provide lenalidomide to patients likely to benefit and obtain additional safety information. Relapsed/refractory MM patients received lenalidomide 25 mg/d (days 1-21) and dexamethasone 40 mg/d (days 1-4, 9-12, and 17-20 of cycles 1-4; days 1-4 only from cycle 5 onwards), in 4-week cycles until disease progression, study drug discontinuation, or lenalidomide approval. Of the 1438 patients enrolled, approximately 60% were male, median age was 64 years, and 61.7% had Durie-Salmon stage III disease. Median time on study was 15.4 weeks (range: 0.1-49.1) and median dose was 25 mg. The most common adverse events (AEs) were haematological (49%), gastrointestinal (59%), and fatigue (55%). The most common grade > or =3 AEs were haematological (45%), fatigue (10%), and pneumonia (7%). The most common serious AEs were pneumonia (8%), pyrexia (4%), and deep-vein thrombosis (3%). Primary cause of death was disease progression (10%). Safety data confirmed known AEs of lenalidomide plus dexamethasone therapy in patients with relapsed/refractory MM.