NEW YORK (Reuters Health) – Men with benign prostatic hyperplasia experience a similar reduction in urinary symptoms whether they’re treated with dutasteride or finasteride, according to the results of the year-long EPICS trial.

Furthermore, the researchers report in BJU international online June 1, “Men treated with finasteride and dutasteride also experienced similar rates of adverse events over the course of 1 year.”

Dutasteride has a longer half-life than finasteride, and so has a greater suppressive effect on serum and intraprostatic levels of dihydrotestosterone — the primary androgen causing excessive prostate growth — explain Dr. J. Curtis Nickel, with Queen’s University in Kingston, Ontario, Canada, and colleagues.

They add that data from the Enlarged Prostate International Comparator Study (EPICS) have been published previously, but the current report is the first time the findings have been published as a peer-reviewed, primary research paper.

The study compared finasteride 5 mg/d to dutasteride 0.5 mg/d for 48 weeks in 1630 men with a clinical diagnosis of BPH. The primary endpoint was change in prostate volume; secondary endpoints were improvements in American Urological Association Symptom Index (AUA-SI) scores and in maximum urinary flow rate.

At 1 year, prostate volume decreased by 26.7% with finasteride and by 26.3% with dutasteride, according to the report.

Corresponding changes in AUA-SI were -5.5 vs. -5.8, and in maximum flow rate they were 1.7 vs 2.0 mL/sec, the results indicate.

During the 1-year trial, adverse events such as impotence, decreased libido and ejaculation disorders were reported by 50% of men on finasteride and 49% of those on dutasteride. Corresponding rates of serious adverse events were 5% vs 7%.

During an optional 24-month follow-on open-label phase, no new adverse events were reported.

“Given the long-term, progressive nature of BPH, the 1-year duration of EPICS may limit the potential to observe major differences between dutasteride and finasteride treatment,” Dr. Nickel and colleagues comment. “As seen in clinical trials of up to 4 years’ duration, BPH symptoms and (maximum urinary flow) may continue to improve over time after the initiation of finasteride or dutasteride therapy.”

EPICS was funded by GlaxoSmithKline, and three of the six authors are employees of the company

Reference:
Comparison of dutasteride and finasteride for treating benign prostatic hyperplasia: the Enlarged Prostate International Comparator Study (EPICS)
BJU Int 2011