The Medical Therapy of Prostatic Symptoms (MTOPS) study was a multi-center, randomized, double-blind placebo controlled clinical trial that tested whether the oral drugs finasteride (Proscar) and doxazosin (Cardura), alone or in combination, could delay or prevent the worsening of symptoms in men with benign prostatic hyperplasia (BPH). Doxazosin is an α-adrenergic receptor agonist (α-blocker) that reduces muscle tone of the prostate and bladder neck, and finasteride is a 5-α-reductase inhibitor that reduces prostate volume by inducing epithelial atrophy. The MTOPS study hypothesized that these two classes of drugs may act synergistically to delay or prevent the clinical progression of BPH.

Participants were randomly assigned, in a double-blind fashion, to one of the following 4 treatment groups: placebo, doxazosin, finasteride, or combination therapy. The primary outcome measure was time to overall clinical progression of BPH, defined as either a confirmed 4 point or greater increase from baseline in the American Urological Association (AUA) symptom score, acute urinary retention, incontinence, renal insufficiency, or recurrent urinary tract infection. The progression of BPH was also assessed using digital rectal examination, serum PSA measurement, urinalysis, transrectal ultrasound, biopsies, urinary flow, and change in the AUA score. The study found that combination therapy with doxazosin and finasteride was more effective than either therapy alone in the preventing the clinical progression of BPH.

The MTOPS study sought to determine whether therapy with finasteride, doxazosin, or a combination of the two agents, prevents or delays the clinical progression of BPH.

The primary outcome measure was time to overall clinical progression of BPH, defined as either a confirmed 4 point or greater increase from baseline in the American Urological Association (AUA) symptom score, acute urinary retention, incontinence, renal insufficiency, or recurrent urinary tract infection. Secondary outcome measures included the need for invasive therapy for BPH and changes in the maximum urinary flow rate, prostate volume and prostate specific antigen (PSA).

Men aged 50 years or older were eligible for the study if they had an AUA symptom score in the range of 8 to 30 during the full-scale study, and had a peak urinary flow rate of 4 mL/s to 15 mL/s. Exclusion criteria included a prior medical or surgical intervention for BPH or a serum prostate-specific antigen (PSA) level higher than 10 ng/mL.

The study found that combination therapy with doxazosin and finasteride was more effective than either therapy alone in the preventing the progression of BPH; the risk of clinical progression was reduced by 39%, 34%, and 67%, in the doxazosin, finasteride, and combination therapy groups, respectively, compared with placebo.

Additionally, both combination therapy and finasteride as a single agent significantly reduced the risk of acute urinary retention (AUR) and BPH-related invasive therapy. Although doxazosin reduced the risk of AUR in the initial 2.5 years of the study, it did not reduce the long-term incidence compared with placebo. In addition, doxazosin did not reduce the long-term incidence of BPH-related invasive therapy.