Two-Drug Therapy is Best for Symptomatic Prostate Enlargement

Two drugs commonly used to treat benign prostatic hyperplasia (BPH) are more effective in combination than alone to prevent progression of this condition, according to results of a multi-center National Institutes of Health clinical trial being presented at the American Urological Association (AUA) meeting in Orlando on May 28.

The Medical Therapy of Prostatic Symptoms (MTOPS) Trial found that compared to placebo the 5 -reductase inhibitor finasteride (Proscar) and -1 receptor blocker doxazosin (Cardura) together reduced the risk of BPH progression by 67 percent. The risk of progression was reduced by 39 percent with doxazosin alone and by 34 percent with finasteride alone.

An estimated 9 million men suffer from BPH symptoms, and about 400,000 have surgery each year to remove some of the enlarged gland, which impairs the flow of urine through the urethra. Symptoms include urinary urgency, frequency, and nighttime urination.

"This is the kind of clear-cut result we all strive for when we launch a clinical trial," says Leroy M. Nyberg Jr., Ph.D., M.D., whose urology research program at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) funded the study. "The evidence supporting combination therapy in selected patients is so strong that I expect to see major changes in medical practice in the near future."

Physicians at 17 medical centers treated about 3,000 men age 50 and up for an average of 4.5 years. The men all had BPH and were evenly divided into four groups that took either 5 mg finasteride, 4 mg or 8 mg doxazosin, both drugs, or a placebo. The aim of the trial was to prevent BPH progression, defined primarily as either a significant worsening of symptoms, recurring urinary tract infection, urinary retention, incontinence or invasive therapy such as surgery.

Compared to placebo, the risk of urinary retention was reduced by 79 percent with combination therapy, by 67 percent with finasteride and by 31 percent with doxazosin (not significantly different from placebo), and the risk of invasive therapy was reduced by 69 percent with the combination, by 64 percent with finasteride and by 8 percent with doxazosin (not significantly different from placebo).

"Combination therapy not only provides better long-lasting symptom relief, but because finasteride reduces prostate size, patients have fewer episodes of urinary retention and invasive treatments," says MTOPS trial leader John McConnell, M.D., professor of urology and executive vice president of the University of Texas Southwestern Medical Center in Dallas. "In addition, the study clearly demonstrates which patients are at increased risk of progression and most likely to benefit from treatment, which we will discuss at the AUA meeting."

When MTOPS began, doctors were prescribing each drug individually for BPH symptoms. But some doctors were concerned that while single-drug therapy provided partial relief, symptoms might worsen over time or the prostate might continue to enlarge, blocking the flow of urine and damaging the bladder and kidneys.

"In MTOPS, the rates of urinary tract infection and urinary incontinence were low in all drug treatment groups, and no patient in any group developed kidney problems from BPH. So we are very pleased," says Nyberg.

Investigators plan to publish study data later this year. The abstract for Dr. McConnell's AUA presentation is available here.

Study Sponsors: The National Institute of Diabetes and Digestive and Kidney Diseases and National Center on Minority Health and Health Disparities funded the study, and Pfizer Inc., New York City; and Merck & Co., Rahway, New Jersey, donated products.

Interview requests for Dr. McConnell: Call Philip Schoch at (214) 648-6315.