BIOSAFETY MONITORING OF PATIENTS RECEIVING INTRACEREBRAL INJECTIONS OF MURINE RETROVIRAL VECTOR PRODUCER CELLS

Patients with recurrent malignant brain cancer, who were receiving gen e therapy by intracerebral injection of murine retroviral vector produ cer cells (VPCs), were monitored for the presence of replication-compe tent retrovirus (RCR), RCR sequences were not detected by polymerase c hain reaction (PCR) in any of the 608 peripheral blood leukocyte (PBL) samples analyzed, Vector DNA sequences were detected transiently in P BL samples from a subset of 34 patients. Humoral immune responses to a retroviral core protein p30 and murine VPC were detected in some pati ents, most frequently in patients receiving repeated administrations o f VPC, RCR was not detected in biological assays of PBLs from 41 patie nts who had either anti-retroviral antibodies in sera and/or vector DN A in PBLs. Our data suggest that in situ generation of RCR was not det ected following intracerebral inoculation of VPCs in any of the 128 pa tients evaluated.