Lenalidomide: new drug. Myeloma: many questions remain unanswered.

(1) Bortezomib prolongs survival in patients with relapsed or refractory multiple myeloma by a few months, but it provokes frequent and sometimes severe adverse effects. Thalidomide is generally used as a last resort; (2) Lenalidomide, a structural analogue of thalidomide, is licensed for the treatment of multiple myeloma, in combination with dexamethasone, after failure of the initial treatment regimen; (3) There are no comparative trials versus bortezomib or thalidomide; (4) Combined analysis of 2 randomised double-blind trials of lenalidomide + dexamethasone versus placebo + dexamethasone in a total of 704 patients showed that adding lenalidomide to dexamethasone slightly increased the one-year survival rate, from 75% to 82%. When this combination was used, the median time to tumour progression was 11 months. In clinical trials, the median time to tumour progression was about 2 years with thalidomide and 8 months with bortezomib; (5) In clinical trials, lenalidomide, like thalidomide, provoked deep venous thrombosis (9% versus 4% with placebo) and pulmonary embolism (4% versus 1%). Lenalidomide, unlike thalidomide, does not appear to cause peripheral neuropathy, but it does provoke cardiac arrhythmia such as atrial fibrillation (18% versus 11% with placebo) and severe haematological disorders, including neutropenia (35% versus 3% with placebo), thrombocytopenia (13% versus 6%) and anaemia (11% versus 6%); (6) The teratogenic effect of lenalidomide has not been adequately documented; (7) Lenalidomide costs about 40% more than bortezomib in France; (8) In patients with relapsed or refractory multiple myeloma there is no evidence that lenalidomide has a more favourable risk-benefit balance than bortezomib or even thalidomide.