Trial of Immunomodulatory Therapy in High Risk Solitary Bone Plasmacytoma

Inclusion Criteria: * Patients with newly-diagnosed SBP * SBP treated with local radiotherapy with curative intent (see appendix 2). * Radiotherapy completed within 28 days of registration * Age ≥18 years * ECOG performance status 0-2 * Written informed consent * Willing to comply with the requirements of the Celgene pregnancy prevention programme Exclusion Criteria: * Multifocal plasmacytoma, solitary extramedullary plasmacytoma or myeloma * ≥10% bone marrow plasma cells * Clinical suspicion of failure to respond to radiotherapy * Receiving or intention to treat with systemic corticosteroid therapy (e.g. dexamethasone or prednisolone) unless otherwise agreed by the TMG * Severe hepatic impairment (bilirubin \>2xULN or AST/ALT \>2xULN) * Creatinine clearance \< 30 mL/min * Pregnant or lactating women * Non-haematological malignancy within the past 3 years (exceptions apply - see section 6.2.2) * Patients at a high risk of venous thromboembolism due to: * Treatment with erythropoietic stimulating agents (e.g. erythropoietin, epoetin alpha, epoetin beta, darbepoetin alfa, methoxy polyethylene glycol-epoetin beta) * Other risk factors not listed above and unable to receive thromboprophylaxis * Patients with untreated osteoporosis * Patients with uncontrolled diabetes * Patients with a known history of glaucoma * Any other medical or psychiatric condition likely to interfere with study participation * Receiving treatment with an experimental drug or experimental medical device. Concurrent participation in non-treatment studies is allowed, if it will not interfere with participation in this study. Any experimental drug treatments must be stopped at least 4 weeks before planned start of lenalidomide and dexamethasone. * Evidence of current or past hepatitis B infection. Patient should test negative for both surface antigen (HBsAg) and hepatitis B core antibody (HBcAb)