Once again, combined therapy shows advantages over monotherapy.
In the previously
published MTOPS trial (Journal
Watch Jan 13 2004), combined therapy with an 
-blocker (doxazosin) and a 5-reductase inhibitor (finasteride) was
superior to monotherapy with either agent in patients with benign prostatic
hyperplasia (BPH). In this new double-blind trial, researchers randomized 4844
men with BPH and prostate volume 
30
mm3 to receive the -blocker tamsulosin (Flomax), the 5-reductase inhibitor dutasteride (Avodart), or
combined therapy. The maker of dutasteride sponsored the trial.
At 2 years, improvement on a standardized 35-point symptom score was significantly greater with combined therapy than with dutasteride or tamsulosin monotherapies (mean decrease, 6.2 vs. 4.9 and 4.3 points from a mean baseline score of 16.4). Tamsulosin has a rapid onset of action, so both tamsulosin and combined therapy outperformed dutasteride during the first 3 months, but combined therapy was superior to both monotherapies during the second year. Drug-related adverse events (most involved sexual dysfunction) were slightly more common with combined therapy then with either monotherapy, but rates of study withdrawal because of adverse events were similar in the three groups.
Comment: These findings mirror the results of the previous MTOPS trial: Combined therapy was somewhat more effective than either monotherapy in patients with symptomatic BPH. Notably, mean baseline prostate size was substantially larger in this study than in MTOPS (55 mm3 vs. 36 mm3). Whether the combination of these newer drugs (dutasteride and tamsulosin) confers any advantage over the older, cheaper, generic drugs (finasteride and doxazosin) is unclear.
Published in Journal Watch General Medicine February 7, 2008
Roehrborn CG et al. The effects of dutasteride, tamsulosin and combination therapy on lower urinary tract symptoms in men with benign prostatic hyperplasia and prostatic enlargement: 2-year results from the CombAT study. J Urol 2008 Feb; 179:616.