|May 24, 2000
NEW ORLEANS (Reuters) - A prostate cancer drug that works more
quickly than existing drugs may provide patients and doctors a
little peace of mind, researchers said on Tuesday.
They said a drug developed jointly by Amgen and Praecis
Pharmaceuticals stops a characteristic ``spike'' in testosterone
levels caused by other prostate cancer treatments.
Dr. John Trachtenberg of the Princess Margaret Hospital in
Toronto said he hoped the drug, called abarelix, might also be a
more effective treatment for prostate cancer, although he stressed
it was too early to tell.
Prostate cancer is the biggest cancer killer of men in the
Western world after lung cancer. More than 180,000 cases of prostate
cancer will be diagnosed in US men this year and nearly 32,000 men
will die of it.
About 85 percent of patients have hormone-dependent prostate
cancer. They can be treated by cutting off testosterone, either by
removing the testicles, where the hormone is produced, or by using a
drug to block production. But, Trachtenberg said, using drugs to
block testosterone often first causes levels of the hormone to
surge. ``Clearly, the aim is to suppress from day one,'' he said in
He told a meeting of the American Society of Clinical Oncology
(ASCO) that abarelix can do that. His team did a phase III trial—an
advanced trial—of 235 men with hormone-dependent prostate cancer.
Half got abarelix and half got TAP Pharmaceuticals' Lupron, a
standard treatment. Both groups also got bicalutamide, another
prostate cancer drug.
Trachtenberg said 80 percent of the men who got abarelix had the
desired testosterone level—the equivalent of castration—after eight
days while none of the men on Lupron did.
After three months both groups of men had the desired
testosterone levels. ``I think it's an elegant drug because it does
what we want,'' he said. He added that more studies are needed to
see whether abarelix helps men live longer and disease-free.
Most anti-testosterone prostate drugs work to increase levels of
a hormone known as luteinizing hormone releasing hormone (LHRH)
antagonists. Abarelix actually works against LHRH, as well as
against follicle stimulating hormone (FSH), and is known as a
gonadotrophin releasing hormone antagonist.
Trachtenberg said some evidence suggests that in men, FSH can
stimulate cancer cells and eventually make them resistant to hormone
therapy. He said abarelix suppresses FSH, too, and he said that
might make these cancers more controllable over the long run.