) Our recent in vitro and preclinical studies have shown that certain human mAbs derived from the V4-34 gene are cytotoxic to normal and malignant B lymphocytes. 216, the most cytotoxic of V4-34 derived Ab from our library, has shown minimum toxicity accompanied by significant protection in a human lymphoma models developed in CB17-scid/scid and NOD/LtSz-scid/scid mice. MAb 216 meets all the criteria for an efficacious treatment. Its ligand does not down regulate and is present on majority of B cell lymphomas. It will be associated with minimal toxicity, side effects and immunogenicity. Toxicity is mediated by two independent mechanisms. The first is effector independent, temperature dependent pathway that cross-links the cytoskeletally associated B cell ligand leading to disruption of the cell membrane integrity. The second is the conventional pathway of complement fixation. Toxicity is B cell specific and will not lead to general immune suppression since stem cells are not affected. Finally this human IgM is easy to prepare and use. In this proposal phase I evaluation of human Ab 216 for treatment of recurrent of B cell lymphoma will be undertaken. Twelve patients with relapsed lymphoma who have failed a least one form of therapy will receive escalating doses of 216, with three patients at each dose level. The initial dose will be 50 mgtm2 with subsequent doses escalated as follows: 100 mg/m2, 250 mg/m2 and 400 mg/m2. The pharmacokinetics, toxicity and efficacy of a single injection will be evaluated. Pharmacokinetics of the 216, serum levels and immune response to the injected Ab will be measured. Peripheral blood B cell levels will be monitored. Patients receiving doses of 100 mg/m2 or greater will undergo fine needle lymph node biopsy on day 14 for analysis of Ah penetration. Tumor response will be assessed. Because this therapy may benefit the patient with B cell lymphoma and would have no benefit for other subjects only lymphoma patients will be studied. There will be no control subjects.
| Liedtke, Michaela; Twist, Clare J; Medeiros, Bruno C et al. (2012) Phase I trial of a novel human monoclonal antibody mAb216 in patients with relapsed or refractory B-cell acute lymphoblastic leukemia. Haematologica 97:30-7 |
