A Phase I Open Label Dose Escalation Study To Evaluate MEDI-507 in Patients with CD2-Positive T-Cell Lymphoma/Leukemia.

This ongoing multicenter study is a Phase I trial with MEDI-507 (Siplizumab) [a humanized IgG1k class monoclonal antibody that binds to the CD2 receptor on human T- and NK-cells] to determine the maximum tolerated dose (MTD) or the optimum biologic dose (OBD) in patients with relapsed/refractory CD2-positive T-cell lymphoma/leukemia [CD2-positive adult T-cell leukemia (ATL), cutaneous T-cell lymphoma (CTCL), peripheral T-cell lymphoma (PTCL), and large granular lymphocytic leukemia (LGL).] Open label 3+3 dose escalation was conducted in which patients receive bi-weekly infusions of MEDI-507 over 3 consecutive days at total doses of 0.7 mg/kg, 3.4 mg/kg or 4.8 mg/kg. Predose and serial MEDI-507 pharmacokinetics (ELISA) at Visit 2 and anti MEDI-507 antibodies (ELISA), peripheral blood total T-Cell and CD2-positive T-cells (flow cytometry), and C3 and C4 complement are obtained for each patient. Patients are followed for one year after their last dose of MEDI-507 for tumor assessment and CD2-positive T-cell recovery. 16 patients have been enrolled: 3 (0.7 mg/kg); 9 (3.4); 4 (4.8). Three additional patients were added to the 3.4 mg/kg cohort to replace patients who progressed early and one patient with tumor lysis syndrome. Diagnoses of the 16 patients: PTCL (9), CTCL (6) and NK-LGL (1). Frequent adverse events reported, to date, are infusion reaction (7/16) patients; hypertension (4/16); lymphopenia (4/16); fatigue (4/16) and leukopenia (3/16). Two DLT’s have been observed. The first, erythematous confluent dermatitis, occurred in one patient at 3.4 mg/kg and the cohort was expanded with eventual dose escalation. The second, pulmonary edema, occurred in one patient at 4.8 mg/kg and the cohort is currently being expanded without further DLT identified to date. Two responses have been observed, one PR in an NK-LGL patient at 3.4 mg/kg and one CR in a PTCL patient at 3.4 mg/kg. MEDI-507 has been well tolerated and shown anti-tumor activity. Dosing will change to weekly dosing with dose escalation (3+3) starting at 1.2 mg/kg as 0.8 mg/kg was seen to be safe in the single center study. MTD and/or OBD have not been determined.