ENZO TREATS FIRST PATIENT IN ANTISENSE GENE THERAPY TRIAL

Enzo Therapeutics has begun treating patients in a Phase I/II clinical trial of the company's gene therapy for HIV-1 infection.

The study is enrolling HIV-1-infected subjects with compromised CD4+ cell counts to determine whether the procedure will create sufficient HIV-1-resistant CD4+ cells to defer disease progression to AIDS. Enrollment is continuing under a modified protocol designed to increase the proportion of engineered stem cells that engraft in the patient's bone marrow.

Enzo's proprietary StealthVector HGTV43 gene construct is used to transfer into the subjects' own stem cells antisense genes designed to interfere with HIV-1 growth. These cells should engraft, replicate and differentiate within the body to produce a population of CD4+ T-cells resistant to HIV-1 infection.

The novel aspect of the current study includes a single outpatient radiation treatment to reduce each subject's total number of stem cells before infusion of the genetically engineered cells in order to increase the proportion of stem cells that contain the anti-HIV-1 antisense genes.

Enzo developed the HGTV43 vector as a proprietary retrovirus-based delivery system designed to overcome a major challenge in gene medicine, namely the safe and efficient delivery of engineered genes to the appropriate target cells. The StealthVector technology achieves efficient delivery of the genes into the patient's cells while being "silent" and unlikely to trigger an immune response, the company said. In addition, critical safety features were incorporated to minimize the possibility of turning on deleterious genes within the body.

The study endpoints are safety of the procedure and the extent of engraftment and proliferation of the engineered cell population. A secondary endpoint is the relationship between the number of antisense RNA-containing CD4+ cells, the HIV-1 viral load and the CD4+ cell count as measured monthly for six months.