However, the drug has yet to prove itself against solid tumors, which are far more common than blood cancers. For those, the most popular apoptosis target is the p53 gene, which plays a role in purging defective cells. P53 is inactivated in more than 50% of solid tumors, and at least four biotech outfits are developing drugs that would turn it back on. Advexin, for example, from Introgen Therapeutics Inc. (INGN ), uses a deactivated virus to deliver a working p53 gene to the patient. Advexin is in phase-3 trials against head and neck cancer and in early tests against lung cancer.
LIFELONG PROTECTION.Cancer patients know all too well that they are never out of the woods. Cancer cells can reappear years after "successful" treatment, and recurrence usually kills. When John L. Willey, 57, was diagnosed with prostate cancer at age 40, he had his entire prostate and surrounding tissue removed, but 12 years later the cancer was back. The father of two sons, now 16 and 10, Willey decided to try buying time with a vaccine that would train his immune system to take out the tumor cells. He enrolled in a clinical trial at Johns Hopkins for GVAX, from Cell Genesys Inc. (CEGE ), and got two shots a week for eight weeks. So far, the cancer has not resumed its spread. "I know I have a disease that is incurable," says Willey. So he is lobbying for enrollment in a trial for a new, stronger version of GVAX.
Immunotherapy is the great hope of many cancer specialists, and the most elusive: It is devilishly hard to get the body to defend itself against a homegrown enemy. Plenty of biotech startups are determined to find a way, and are responsible for some 70 vaccines in development. New York's tiny Antigenics (AGEN ) is a case in point: Its skin cancer vaccine, HSPPC-96, generated considerable buzz in October when data from a phase-1 trial showed that it eliminated tumors in 2 of 28 patients with advanced skin cancer, and stabilized the disease in three.
These drugs have more safety hurdles to overcome than other treatments, however. Because cancer cells so closely resemble normal ones, there is a danger that a stimulated immune system will go after both. It doesn't help that many of the early candidates failed clinical trials. This year, however, 29 cancer vaccines are in late-stage trials. "I think several of these have a good chance of success," says Monane.
Of course, all of these initial targeted therapies could wash out. But researchers insist that early failures should not discredit the entire field. "There could be a problem with the design of the clinical trial, or a drug may need to be tweaked to improve its effectiveness," says Dr. Geoffrey Duyk, chief scientific officer of Exelixis Inc., which has several drugs in preclinical development. "I think the biggest threat to the whole field of cancer research is people giving up too soon." One need only listen to patients to realize this truth.
Perry Colmore, a 60-year-old former newspaper editor in Massachusetts, was diagnosed with breast cancer in 1987. She had one breast removed, and the second one in 1995 when the cancer returned. By then, the disease had spread to her lymph nodes. "I figured I was dying and was ready to give up," she says, "but a wonderful social worker convinced me to keep going." Colmore went through a brutal chemo regimen at Boston's Beth Israel Deaconess Medical Center, 35 rounds of radiation, and took tamoxifen, a hormone- based treatment, for six years. She also started meditating, gave up drinking, changed her diet, and moved from a Boston suburb to Martha's Vineyard. Six months ago, she started a clinical trial for Femara, a promising breast cancer drug from Novartis. She has suffered from multiple side effects from all these treatments, among them pleurisy, asthma, arthritis, and weight gain. Still, "asthma's a lot better than being dead," she says flatly. "It's pretty annoying that we don't have a a cure and we don't even know why we're getting cancer," Colmore admits. Nevertheless, "I have a feeling a lot of miracles are being worked."
Copyright 2002, Bloomberg L.P.
Printer-Friendly Version
