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SOUTH SAN FRANCISCO, Calif.—After learning from an independent committee of experts that its experimental therapy GVAX for prostate cancer was unlikely to deliver positive results, Cell Genesys Inc. announced Oct. 16 that it would pare its workforce of 290 employees by 75 percent and cancel work on its lead product.
In a conference call, Dr. Stephen A. Sherwin, chairman and CEO of Cell Genesys, said the company was pulling the plug on the VITAL-1 Phase III clinical trial of GVAX immunotherapy in patients with asymptomatic metastatic hormone-refractory prostate cancer.
What is next for the South San Francisco-based company is unclear.
Sherwin said the company has held discussions with Takeda Pharmaceutical Co. Ltd., its research partner on the GVAX program. He added that researchers at Johns Hopkins may still proceed with their own trials of GVAX for leukemia and pancreatic cancer. Takeda also has halted its own development of the drug candidate.
As for the VITAL-1 Phase III trial, Sherwin pointed out it was fully enrolled last year with 626 patients and compared GVAX immunotherapy to Taxotere chemotherapy plus prednisone.
By this summer, the trial seemingly began to unravel. In August, Cell Genesys announced it had requested that the Independent Data Monitoring Committee conduct a futility analysis of the VITAL-1 trial following the termination of VITAL-2, the company's other Phase III trial of GVAX immunotherapy for prostate cancer. Cell Genesys' management team decided to terminate the trial based on the committee's finding that it had less than a 30 percent chance of meeting its predefined primary endpoint of an improvement in survival.
After terminating the VITAL-1 and VITAL-2 trials, Cell Genesys also put on hold continued development of GVAX immunotherapy for prostate cancer pending a review of the program with Takeda.
"We are disappointed with the outcome of the futility analysis for the VITAL-1 Phase III clinical trial," Sherwin says. "I believe we can and will learn from these trials. I don't believe our efforts are wasted."
Despite the setback, Sherwin remains committed to immunotherapy as a potential treatment for prostate cancer.
"Personally, I have not lost my conviction about the potential of the GVAX platform or active immunotherapy in general," he says. "I believe that immunotherapy will play a role in the treatment of this disease."
The August revelation by the same expert panel led to a halt in a related trial amid safety concerns. The panel discovered that GVAX-treated prostate cancer patients in that trial were dying at a higher rate than those given a different treatment.
According to Sherwin, there was no evidence that the GVAX regimen carried any toxic effects that could explain the additional deaths. He said other factors, including the chemotherapies used on the patients, may have had an impact.
Despite the cessation of the GVAX program in prostate cancer, Cell Genesy still has other GVAX products in the pipeline for other indications including leukemia and pancreatic cancers, both in Phase II and in lung cancer, now in preclinical development.