Viagene Inc. has begun a gene therapy study to determine if itsretroviral vector can deliver an interferon-gamma gene in vivo tocancer tumor cells in an effort to trigger an immune response againstthe malignancy.
James Merritt, Viagene's vice president of medical affairs, said thePhase I studies will involve 24 cancer patients at the Hoag Hospitalin Newport Beach, Calif., and the Texas Oncology PhysiciansAssociation in Dallas.
Viagene, of San Diego, uses a retroviral vector based on Moloney'svirus, a lymphoid leukemia virus of mice. By transducing the genefor interferon-gamma to the cancer cells, the intention is to trigger animmune system assault on the tumor by lymphocytes andmacrophages.
In the current Phase I studies, the vectors with the interferon-gammagenes are injected directly into a tumor. Following the treatments,patients' tumors will be removed and analyzed to determine if thegenes were transferred to the cancer cells.
Subsequent studies, Merritt said, will evaluate the immune responseand determine if it attacks tumors throughout the body.
Viagene has four other Phase I cancer studies under way where thesame vector is used to insert the interferon-gamma gene into tumorcells ex vivo. Those modified cells are then reinfused in the patient inthe hopes of generating an immune response. One trial is completeand the data are being evaluated.
Merritt said the retroviral vector being used is the same one involvedin its Phase II HIV gene therapy studies. To date, he added that thevector has been injected in about 200 patients and has not generatedany safety problems.
In April, Viagene agreed to a buyout proposal from Chiron Corp., ofEmeryville, Calif. Chiron, which owned 17 percent of Viagene,agreed to pay $95 million in cash and stock to acquire the remainingshares of the company. _ Charles Craig
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