Lung Cancer Vaccine Demonstrates Enhanced Antitumor Immunity

Ravi Salgia, MD, PhD, and colleagues at Dana-Farber Cancer Center presented an encouraging follow-up report on an initial clinical trial of Cell Genesys’ GVAX lung cancer vaccine at the Ninth World Conference on Lung Cancer in Tokyo, Japan. The trial was conducted in patients with advanced non-small-cell lung cancer, the majority of whom had failed prior treatment with surgery, radiation, and/or chemotherapy.

Of 25 patients who received the complete course of vaccinations, 18 demonstrated enhanced antitumor immunity as measured by delayed-type hypersensitivity skin reactions. In addition, 2 patients continued to experience disease-free survival for more than 2 years after treatment and 3 other patients were reported to have stable disease without evidence of tumor progression after 15, 8, and 4 months, respectively. Treatment with the GVAX vaccine was safe and well tolerated in the outpatient setting, the investigators noted.

This initial clinical trial of the GVAX vaccine in lung cancer is evaluating a patient-specific product format in which the vaccine is prepared from the patient’s own tumor cells. The feasibility of this approach was demonstrated by the successful preparation of the vaccine for over 90% of patients enrolled in the study.

Phase I/II Trial Initiated

Based on the results of the initial trial, Cell Genesys initiated a multicenter phase I/II trial of the GVAX lung cancer vaccine in patients with both early-stage and advanced non-small-cell lung cancer. More than 35 patients have been enrolled in this trial to date. In addition, Cell Genesys plans to develop a non-patient-specific GVAX product for lung cancer, because other non-patient-specific GVAX vaccines have previously been reported to demonstrate encouraging results in initial clinical trials in prostate cancer and pancreatic cancer.

"We are encouraged by the longer-term follow-up report on this initial GVAX lung cancer vaccine trial, particularly since lung cancer has been largely unresponsive to other immunotherapies to date," said Joseph J. Vallner, PhD, executive vice-president and chief operating officer at Cell Genesys. "GVAX cancer vaccines have now demonstrated antitumor activity in all five cancers tested to date, including prostate cancer, lung cancer, pancreatic cancer, kidney cancer, and melanoma."

Tumor Cell Modified and Irradiated

GVAX cancer vaccines are comprised of tumor cells that have been genetically modified to secrete granulocyte-macrophage colony-stimulating factor. The genetically modified tumor cells are then irradiated for safety and used to vaccinate patients to stimulate an immune response against their tumor. The company’s lead GVAX cancer vaccine program targets patients with recurrent prostate cancer and is currently being evaluated in two multicenter phase II trials. Additionally, a phase II trial of the GVAX pancreatic cancer vaccine and phase I trials of the GVAX vaccine for myeloma and leukemia are expected to begin by early 2001.

At the American Society of Clinical Oncology meeting in May 2000, Cell Genesys announced encouraging data from a phase I trial of a GVAX pancreatic cancer vaccine and a preclinical trial of a GVAX vaccine for leukemia. In a human clinical trial in 14 pancreatic cancer patients conducted at the Johns Hopkins Oncology Center, 3 of 8 patients who received the two highest doses of the vaccine are alive and free of disease more than 2 years later, whereas all 6 patients receiving the two lowest doses have relapsed. These patients received the vaccine following surgery and adjuvant radiation and chemotherapy.