Phase I HIV Gene Therapy Trial Shows Promising Results
Four of five subjects show improved immune response without adverse side effects
WEDNESDAY, Nov. 8 (HealthDay News) -- A phase I trial in which five HIV-infected patients were treated with a conditionally replicating, therapeutic lentiviral vector targeting HIV suggests that the treatment is safe and has not caused insertional mutagenesis or emergence of replication-competent lentivirus, according to results published online Nov. 7 in the Proceedings of the National Academy of Sciences Early Edition.
After approval by multiple clinical review boards, Carl June, M.D., of the University of Pennsylvania in Philadelphia, and colleagues gave five HIV-infected patients who were previously unresponsive to two antiviral regimens a single infusion of gene-modified autologous T-cells containing antisense sequence targeting the HIV envelope.
The infusion was well tolerated in all five subjects, the authors note. Viral loads remained stable and even decreased in one subject while CD4 counts remained steady and increased in four subjects. Immune function improved in four subjects as well. No insertional mutagenesis or replication competent lentivirus was noted after 21-36 months of observation.
Because the therapeutic lentivirus is a modified form of the AIDS virus, it acts like a Trojan horse, the authors suggest. The virus replicates and shuts viral production only in HIV-infected cells. "The results support the clinical promise of gene transfer using lentiviral vector technology," the authors write.
Several of the authors were employees of VIRxSys Corporation, the manufacturer of the lentiviral vector used in this report, at the time the study was performed.