Lung Cancer Vaccine Demonstrates Enhanced Antitumor Immunity

Ravi Salgia, MD, PhD, and colleagues at Dana-FarberCancer Center presented an encouraging follow-upreport on an initial clinical trial of Cell Genesys’ GVAX lung cancer vaccineat the Ninth World Conference on Lung Cancer in Tokyo, Japan. The trial wasconducted in patients with advanced non-small-cell lung cancer, the majorityof 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-typehypersensitivity skin reactions. In addition, 2 patients continued to experiencedisease-free survival for more than 2 years after treatment and 3 other patientswere reported to have stable disease without evidence of tumor progression after15, 8, and 4 months, respectively. Treatment with the GVAX vaccine was safe andwell tolerated in the outpatient setting, the investigators noted.

This initial clinical trial of the GVAX vaccine in lung canceris evaluating a patient-specific product format in which the vaccine is preparedfrom the patient’s own tumor cells. The feasibility of this approach wasdemonstrated by the successful preparation of the vaccine for over 90% ofpatients enrolled in the study.

Phase I/II Trial Initiated

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

"We are encouraged by the longer-term follow-up report onthis initial GVAX lung cancer vaccine trial, particularly since lung cancer hasbeen largely unresponsive to other immunotherapies to date," said Joseph J.Vallner, PhD, executive vice-president and chief operating officer at CellGenesys. "GVAX cancer vaccines have now demonstrated antitumor activity inall 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 beengenetically modified to secrete granulocyte-macrophage colony-stimulatingfactor. The genetically modified tumor cells are then irradiated for safety andused to vaccinate patients to stimulate an immune response against their tumor.The company’s lead GVAX cancer vaccine program targets patients with recurrentprostate cancer and is currently being evaluated in two multicenter phase IItrials. Additionally, a phase II trial of the GVAX pancreatic cancer vaccine andphase I trials of the GVAX vaccine for myeloma and leukemia are expected tobegin by early 2001.

At the American Society of Clinical Oncology meeting in May2000, Cell Genesys announced encouraging data from a phase I trial of a GVAXpancreatic cancer vaccine and a preclinical trial of a GVAX vaccine forleukemia. In a human clinical trial in 14 pancreatic cancer patients conductedat the Johns Hopkins Oncology Center, 3 of 8 patients who received the twohighest doses of the vaccine are alive and free of disease more than 2 yearslater, whereas all 6 patients receiving the two lowest doses have relapsed.These patients received the vaccine following surgery and adjuvant radiation andchemotherapy.