The aim of this phase 2 study is to demonstrate that KIR-ligand mismatched haploBMT with post-transplant cyclophosphamide will improve progression free survival in poor risk multiple myeloma patients.

The goal of this study is to evaluate the effectiveness of a new treatment modality, the KIR-ligand mismatched haploidentical stem cell transplantation (haploBMT), for poor risk multiple myeloma (MM) patients. MM is a malignancy of plasma cells that usually resides in the bone marrow. Despite new treatment modalities that have been introduced in the last years, MM is still an incurable disease for most patients and median survival for the younger patients (<65) is about 5 years. MM can be treated by several disease modifiers - classical chemotherapy, high dose chemotherapy and autologous stem cell transplantation (ASCT), immunomodulators like thalidomide and lenalidomide, and drugs like bortezomib that interact with relevant intracellular pathways of malignant plasma cells. Though these treatment modalities have improved overall survival and quality of life, patients are not cured.

Inclusion Criteria:

• Patients with MM <60 years.

• Poor prognosis MM patients, permissive for KIR-ligand mismatch and with a KIR-ligand mismatched haploidentical donor. Poor prognosis is based on:

  • Patients with early disease recurrence (within 12 months after first ASCT) or
  • Patients after a minimum of three lines of chemotherapy (including high dose therapy followed by ASCT rescue therapy) or
  • Poor risk based on the cytogenetic profile.

• Written informed consent

• No HLA identical related or 10/10 matched unrelated donor

• Permissive for KIR-ligand mismatch

• Responsive after reinduction therapy

• Measurable disease

Exclusion Criteria:

• - Patients with an full matched (10/10) donor, who will enroll in the HOVON 96 study
• Active uncontrolled infections
• Uncontrolled CNS involvement by the malignant disease
• Severe cardiovascular disease (arrhythmias requiring chronic treatment, congestive heart failure or symptomatic ischemic heart disease)
• Severe pulmonary dysfunction (CTCAE grade III-IV)
• Severe neurological or psychiatric disease
• Significant hepatic dysfunction (serum bilirubin or transaminases ≥ 3 times upper limit of normal)
• Significant renal dysfunction (creatinine clearance < 30 ml/min after rehydration)
• History of active malignancy during the past 5 years with the exception of basal carcinoma of the skin or stage 0 cervical carcinoma
• Any psychological, familial, lingual, sociological and geographical condition potentially hampering compliance with the study protocol and follow-up schedule
• Breast-feeding female patients.
• Concurrent severe and/or uncontrolled medical condition (DM, hypertension, cancer).