Tuesday, May 17, 2011
CLINICAL TRIAL FOR GENE THERAPY: THE STEPS OF THE PROTOCOL
Randomized Phase IIb safety and the ability to mobilize CD34 + hematopoietic stem cells by the use of G-CSF vs. G-CSF vs. Plerixafor + Plerixafor in patients with ß-Thalassemia Major "
The beta-thalassemia represents a group of congenital anemias caused by the absence or insufficient production of hemoglobin beta chains. The only chance of a cure, actually, is given by the "allogeneic bone marrow transplantation from HLA-compliant." However, only a limited number of patients is an HLA-compatible and can therefore undergo this procedure. Transplantation is also burdened by a certain percentage of mortality (~ 6%) and peri-and post-transplant. The majority of patients (who can not find a donor HLA-compatible) undergo transfusion therapy associated with chelation therapy .
GENE THERAPY
An attractive alternative, in place at the experimental stage, is the "gene therapy" : is the insertion of the ß-globin gene of hemoglobin in human hematopoietic stem cells harvested from patients with thalassemia, and reinfusion of these cells genetically modified in the same patient undergoing conditioning therapy. To do this recombinant lentiviral vectors were created for the β-globin gene of human (tested successfully in vitro and in animal models of thalassemic mice), one of these carriers has recently been used in two patients in a French trial a second carrier ( Thalagen ) will soon be tested on humans in a clinical trial of gene therapy to be held in collaboration with our group at Memorial Sloan-Kettering Cancer Center (MSKCC) in New York (USA) .
The phases of this protocol include :
- Mobilization of CD34 + stem cells with G-CSF;
- Apheresis CD34 + stem cells;
- Transduction of CD34 + selected with the same lentiviral vector Thalagen;
- The conditioning therapy followed by reinfusion of stem cells transduced.
This protocol has been approved by the RAC (Recombinant Advisory Committed), because there are no data in the literature on the feasibility of the procedure for mobilization of stem cells in thalassemia patients, the Food and Drug Administration has requested a "Phase I study of mobilization and apheresis in patients with thalassemia " , before giving final approval to the gene therapy protocol. It 'was therefore carried out a pilot study (N ° identification: NTC000658385 on clinicaltrials.gov) to assess the feasibility and safety of using G-CSF mobilization of CD34 + stem cells of 5 patients with β-thalassemia (4 patients enrolled at Hematology Unit of the Hospital of the Company II. Reunited Villa Sofia - Brain of Palermo and 1 at the MSKCC, New York), with the aim to obtain: 2-8 x-purified CD34 + PBSC 106/Kg transduction ex- Live, 2 x 106/Kg PBSC CD34 + as a possible back-up. The inclusion and exclusion criteria are listed in Table 1. Inclusion criteria: Exclusion criteria: Age ≥ 18 y Pcs of any gender or ethnic origin Patient with a confirmed diagnosis of ß-thalassemia major under ipertrasfusionale (≥ 100 mL / kg of blood transfusion of ≥ 8 and a minimum of 2 yr ). Patient with Karnofsky performance> 70. Pcs splenectomized or spleen is not palpable Patients must have discontinued HU or EPO at least 3 months before study entry must have a pc I echocardiographic (EF> 50%) and chest X-ray normal. Negative pregnancy test active infections, including hepatitis B and C, HTLV 1 and 2, and HIV 1 and 2 Diabetes Mellitus Patients with uncontrolled seizure disorders Patients with severe pulmonary hypertension or allergy to G-CSF produced from E. History of thrombosis or thrombophilia coli known. Table 1
The protocol was found to be safe , because the side effects that occurred were mild (bone pain, headache and fatigue in 4 / 5 patients in the last 2 days of treatment, pain at the insertion of central venous catheter in the patient 3 ° - the only one to require a central street for collection).
Results
The results have shown the ability to mobilize and collect this protocol with a quantity of CD34 + cells sufficient for subsequent clinical application of gene therapy: ( 8-12x106/Kg CD34 + ). The cells were transduced with an average of 0.8-1 copies per cell of vector (values that fall within the range suggested by the FDA for approval of gene therapy protocol). It awaits final approval by the FDA for the continuation of the study.
Meanwhile, it has been approved by the Ethics Committee of the Hospital Villa Sofia-V. Brain, a study aimed at assessing, in addition to the safety, efficacy of mobilization of different protocols for administration schedule and mechanism of action. This protocol is the result of a collaboration between the Hematology I, II and Hematology Transfusion Medicine of the Hospital Vincent Brain.
OBJECTIVES OF THE PROTOCOL
The protocol provides a Randomized Phase IIb on the capacity and safety of mobilization of hematopoietic stem cells CD34 + by the use of G-CSF vs. Plerixafor vs. G-CSF + Plerixafor in patients with beta-Thalassemia Major " has as main objectives the evaluation of 'effectiveness of mobilization with G-CSF vs. G-CSF vs. Plerixafor + Plerixafor in patients with β-Thalassemia Major and to evaluate side effects among the three arms of the protocol.
The secondary objectives are to evaluate the potential of clonogenic cells mobilized in the three study groups and the efficiency of cross-infection in CD34 + cells collected with a vector encoding the gene for human ß-globin (Thalagen).
The 54 patients for the study will be selected from the pool of subjects with a confirmed diagnosis of thalassemia ß-Thalassemia Major and will be recruited from the Hematology Unit II of the Hospital "Ospedali Riuniti Villa Sofia-Brain". Each participant (chosen on the basis of the criteria listed in Table No. 2 ) will sign consents for the study (Consent to Privacy, Informed Consent and Consent to search) and, if after making appropriate counseling and testing pre-treatment, will randomized into one of three mobilization groups: group A (G-CSF), group B (Plerixafor) or group C (G-CSF + Plerixafor). The patient will then undergo therapy followed by mobilization of CD34 + stem cell collection by apheresis sessions 1-2.
Cells collected are then performed the counting flow cytometry of CD34 + and CD3 + T lymphocytes, assessment of the degree of stem cell / cell differentiation (by testing, flow cytometry and essays clonogenic in vitro) and assessing the ability to be transduced by Thalagen ( with evaluation of proviral DNA and determination of the number of copies of vector per cell).
Participated in the study :
UOC for Hematology and Blood Diseases Rare-forming organs : Santina Acuto, Rita Barone, Aurelio Maggio, Gaetano Restivo;
UOC Haematology with Bone Marrow Transplantation : Alessandro Indovina, Alessandra Santoro, Rosanna Scimè;
Transfusion Medicine : Gaetano Lucania, Renato Messina.
Centres that wish to receive more information may contact the Foundation Franco Cutino and Piera , who has supported the development of the protocol and followed patients for pre-clinical testing, by sending an e-mail at info@pieracutinpo.it . The Foundation will send the request for information to the physician who led the study.