The purpose of this study is to determine wether activated and expanded autologous Natural Killer cells (NKAEs) are effective in the treatment of patients with multiple myeloma on second or later relapse. NKAEs are used in combination with anti-myeloma drugs such as lenalidomide or bortezomib.

It is expected to enroll 10 to 15 patients within 18 months. Patients have to achieve stable disease after induction therapy. Peripheral blood from patients will be collected every cycle (n=4) to produce NKAEs under Good Manufacturing Practice (GMP) conditions peripheral blood mononuclear cell (PBMCs) will be co-cultured with a genetically modified cell line (K562-mb15-41BBL) and 100 IU/ml interleukin-2.

Treatment consists of 4 cycles of anti-myeloma consolidation treatment with two infusions of NKAEs every day 1 and 8 of each cycle. Usually, chosen treatment regime will be bortezomib (Velcade) or lenalidomide (Revlimid). These treatments are used to be combined with corticosteroid medications which needs to be suspended before NKAEs infusions. A washout period of 2 weeks is required.

NKAEs dose of cells will be constant, 7.5x106/kg. There will be an interim analysis intra-cohort one week after the first batch of two infusions. If at the analysis no grade IV adverse effect is observed we will proceed to the second cycle and the inclusion of other patients.

Inclusion Criteria:

• Subjects between 20 and 80 years old
• With multiple myeloma in 2nd or later relapse or showing resistance after 2 treatment lines
• Eastern Cooperative Oncology Group (ECOG) ≤ 2
• Life expectancy greater than six months
• Creatinine clearance rate more than 30 ml / min
• Subjects who have received at least 4 cycles of rescue treatment under the procedures of the 12 de Octubre Hospital (rescue treatment will vary depending on previous anti-myeloma treatment). After treatment, patients must have shown chemosensitivity and disease stabilization.
• Will be included subjects with partial response or stable disease (for at least 2 cycles) after 75% of planned rescue treatment or patients at subclinical progression (defined as an increase of monoclonal component ≥ 25%) at any time of rescue treatment. Subjects have to show tolerance to rescue treatment, without G3/4 adverse effects, if G1/2 adverse effects exist they must be analyzed immediately before starting reinfusion program.
• Subjects have to agree to participate in the trial and they have to sign informed consent.

Exclusion Criteria:

• Subjects with clinical progression or complete response will not be included.
• Any of the following abnormal laboratory results:

Absolute Neutrophil Count < 1000/ µL Platelets Count < 50000/ µL in those patients with bone marrow infiltration lower than 50% Measured creatinine clearance <30 ml/min Hemoglobin level ≤ 8 g/dL Peripheral neuropathy ≥ Grade 2

• Subjects have received allogeneic stem cell transplant.
• Subjects with heart disease which compromises patient's life or protocol accomplishment.
• Subjects with past clinical history of malignant disease within 3 years (exceptions are squamous or basal cell carcinoma).
• Subjects receiving another investigational drug or having received investigational drug within 30 days before screening.
• Subjects who require chronic steroid or immunosuppressive treatment.
• Any condition, including abnormally laboratory results, that might compromise the patient´s life if he participate in this study.
• Any concurrent medical condition, abnormally laboratory results or any psychological disorder that prevent the patient to sign the informed consent.
• Pregnant or fertile women.
• Patients known to be seropositive for human immunodeficiency virus (VIH) or having active hepatitis A, B or C.

The number of participants was directly related with the cost of expanded and activated NK cells production.

4 months during treatment with NKAE cells.

Volume of the peripheral blood from patients was limiting in order to perform different cohorts with more NKAE cells infusions.