Doctors say drug slows prostate cancer

A drug commonly used to treat prostate cancer in the late stages shows great promise when used in earlier stages in a triple dose say two Canadian doctors in charge of a large world medical trial. 

Eight thousand men with prostate cancer took part in a trial using the anti-hormonal drug bicalumatide. Its trade name is Casodex. The random double blind trial was sponsored by the drug’s maker, AstraZeneca.

The study results showed that 150 mg. of Casodex per day reduced the disease progression by 42 per cent and the spreading of the cancer to the bones by 33 per cent, said Dr. Yves Fradet.  He’s a urology surgeon and chairman of the Department of Surgery at Laval University. He led the two-year drug trial.

He emphasized that bicalumatide was used along with standard treatment for prostate cancer. This involves surgery, radiation therapy and monitoring of the blood for prostate cancer indicators.

New hope
“These results add a whole new hope to the quality of treatment for prostate cancer. The risk of disease progression was significantly less in the control group,” says Dr. Jack Barkin chief urologist at Humber River Region Hospital in Toronto. He and Dr. Fradet presented the Casodex results at a media conference in Toronto on June 20th.

“Every urologist in the world knows this drug. It has been out there and used as an anti-hormonal drug. What’s different here is the dose, and it’s use in conjunction with standard treatment,” said Dr. Barkin.

Dr. Fradet says Casodex is already approved for use in 50 mg. doses in the late stages of prostate cancer. Now, the 150-mg. dose for early stage use has been submitted to Health Canada. It usually takes about six months for approval, he says.

Survival rate
“We will follow the eight thousand men to see if the two-year treatment has an impact on survival”-but until more time has passed, he says doctors won’t know if this treatment is useful for preventing more deaths from prostate cancer.

Prostate cancer is the number two cancer killer, after lung cancer, for men. In Canada, it’s expected that 18,000 men will be diagnosed with prostate cancer this year. It’s also a cancer seen most commonly in men age 50plus.

“We can’t comment on survival-but a 42 per cent decrease in disease progression is very dramatic results. For me, as a clinician, this adds new hope for the treatment of cancer patients. We now have an effective drug therapy to add to the primary therapy,” said Dr. Barkin.

Dr. Barkin says this is the first analysis of this world trial of Casodex. The eight thousand men taking part came from 23 countries. Participants included 318 men in 14 cities across Canada. The men were selected at random to take either Casodex or a placebo.

It was also a double blind trial, meaning neither doctor nor patient knew who had the drug or the placebo. In medical circles, randomized double blind trials are the highest standard. The two doctors say the results have been presented to medical conferences in Europe and the U.S. and will appear in medical journals in the fall.

Bone loss
Bicalumatide is a drug which works on the hormonal system. It blocks the uptake of the male hormone testosterone in the cancer cell. It’s testosterone which makes prostate cancer grow, according to both doctors.

Other recent tests of testosterone reducing drugs have shown an alarming loss of bone density for men on these types of drugs. A study published in the June 2001 issue of the Journal of Clinical Endocrinology and Metabolism compared bone loss of 60 men with prostate cancer compared to 197 healthy men. A third of the men with cancer were taking hormone therapy and 60 per cent of these had brittle bones or osteoporosis.

But Dr. Barkin says this was not the case with Casodex: “We have tremendous knowledge of the side effects. We know what to expect. We expected to have loss of bone mineralization. That was not the case.”

“This is one way of doing hormone treatment with fewer side effects. We are seeing the same bone levels in patients on this drug,” added Dr. Fradet.

Side effects
The doctors say the only side effects known so far are breast tenderness and enlargement, which they called “cosmetic problems.”

Dr. Barkin also says another significant result is the 60 per cent reduction in the progression of PSA, the prostate specific antigen or protein which shows up in the blood as a indicator of prostate cancer. He says doctors use the PSA test plus rectal examination to detect prostate cancer. The early symptoms are bladder irritation, frequency of urination or blood in the urine.

When there is some presence of PSA in the blood, many doctors will use a treatment of “watchful waiting” as prostate cancer develops slowly.  If the PSA count rises, then they’ll go to the next treatment levels of radical surgery and radiation, according to Dr. Barkin.

“These are encouraging results-but any treatment is a decision between a patient and his doctor,” he said.

According to AstraZeneca, Casodex costs $6.44 per 50-mg. dose. A package of 30 tabs sells for $193.20 plus dispensing fee.