A GenVec Inc. drug designed to enhance the effects of radiation therapy in cancer patients showed promise in an early-stage clinical trial, according to results presented yesterday at a scientific conference in San Francisco.
Tumors injected before radiation with the gene-therapy drug TNFerade shrank in all seven patients in the trial, with tumors treated in two patients disappearing entirely, the company said.
Meanwhile, "control" tumors did not shrink when treated with the same doses of radiation alone in some of the same patients.
The test results, however, do not mean the patients, all of whom were not helped by other therapies and were extremely sick by the time they enrolled in the Phase I trial, were cured, the company cautioned.
The drug did not appear to cause any serious side effects.
Executives of Gaithersburg-based GenVec said yesterday that they are excited about the results, and Chief Executive Officer Paul Fischer said the company is laying plans for a series of more definitive human tests next year. One of the diseases the company is exploring: pancreatic cancer, a disease that kills 28,000 Americans a year and has no truly effective treatment.
"GenVec expects to do several Phase II trials," Fischer said. "We'll start one in the middle of the year, one in the fourth quarter and one" in 2003.
TNFerade contains a gene that directs the production of the anti-cancer protein TNF-alpha. Once inside the tumor, TNFerade is designed to begin production of TNF-alpha when hit by radiation.
Eight patients have been treated in the trial, with one dropping out before completing it. The trial called for patients to get TNFerade injections directly into accessible tumors one to two times a week for up to six weeks while getting their standard doses of radiation therapy.
Results presented yesterday at the American Society of Therapeutic Radiology and Oncology meeting in San Francisco were for the two lowest dose levels.
The trial is continuing, with up to five dose levels planned. Three to six patients are enrolled at each dose.
At the two lowest dose levels, two out of seven patients completing the trial had a complete response, meaning the tumors treated shrank 100 percent. Two showed a partial response, meaning tumors treated with TNFerade shrank more than 50 percent after radiation. Three patients demonstrated stable disease, meaning that - while their tumors shrank - they did not shrink by more than 25 percent.
"An objective tumor response rate of four of seven patients at the lowest dose levels is highly unusual in a Phase I cancer trial," said Dr. Henrik Rasmussen, GenVec's vice president for clinical and regulatory affairs.