Lenalidomide maintenance combined with Bortezomib following tandem autologous stem cell and non myeloablative allogeneic transplantation for patients with multiple myeloma <= 66 years.

-Age 18-66 years;
-Patients with, before start of induction therapy, a confirmed diagnosis of multiple myeloma stage II or III according to the Salmon & Durie criteria (see appendix A), included in or treated according to the HOVON 65/GMMG-HD4, HOVON 95 or treated according to the guidelines of Hovon Myeloma Study Group for patients <= 66 years group;
-Patient has received 3 cycles induction therapy, followed by stem cell mobilization and 1 cycle of high dose Melphalan with autologous stem cell reinfusion;
-Allogeneic transplantation planned between 2 and 6 months after autologous SCT;
-WHO performance status 0-2 (see appendix D);
-HLA-identical family donor;
-Disease free of prior malignancies for >= 5 years with exception of currently treated basal cell, squamous cell carcinoma of the skin, or carcinoma *in situ* of the cervix or breast.
-Written informed consent for allo SCT treatment as well as lenalidomide maintenance, preferably signed in the presence of both patient and investigator and signed on the same date.;Eligibility for Lenalidomide maintenance combined with bortezomib:
- Laboratory test results within these ranges:
*Absolute neutrophil count >= 1.0 x 109/L
*Platelet count >= 75 x 109/L
*Serum creatinine cleareance >= 50 ml/min
*Total bilirubin <= 30 µmol/l
*AST (SGOT) and ALT (SGPT) <= 3 x Upper Limit of Normal (ULN);
-Negative pregnancy test before inclusion if female of child baring potential;
-Sexually active women of child bearing potential must agree to use 1 adequate contraceptive method while on study drug (and 4 weeks before and after study drug) (for detailed information see section 9.2.2);
-Men must agree not to father a child and to use a condom if his partner is of childbearing potential.

-Creatinin clearance < 50 ml/min;
-Severe cardiac dysfunction (NYHA classification II-IV, see appendix E);
-Significant hepatic dysfunction (serum bilirubin >= 30 micromol/l or transaminases >= 2.5 times normal level), unless related to myeloma;
-Known positive for HIV;
-Patients with active, uncontrolled infections;
-Patients with brain disease with the exception of those patients whose brain disease has been treated with either radiotherapy or surgery and remains asymptomatic, with no active brain disease, as shown by CT scan or MRI, for at least 6 months;
-Progressive disease / relapse from CR / progression from MR or PR after HDM with autologous stem cell reinfusion;;Exclusion criteria for lenalidomide maintenance combined with bortezomib:
-Progressive myeloma (see appendix B)(within 3 weeks before start therapy, response must be checked and patients who developed progressive myeloma must be excluded);
-Acute Graft versus host Disease >= grade 2 (at time of registration);
-Pregnant or lactating females;
-Concurrent use since NMA Allo SCT of other anti-cancer agents or treatments or use of any other experimental drug or therapy within 28 days of planned start lenalidomide;
-Known hypersensitivity to thalidomide;
-The development of erythema nodosum if characterized by a desquamating rash while taking thalidomide or similar drugs;
-Any prior use of lenalidomide;
-Severe cardiac dysfunction (NYHA classification II-IV, see appendix E);
-Polyneuropathy >= grade 2