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

Study Type – Therapy (RCT) Level of Evidence 1b What’s known on the subject? and What does the study add? Both dutasteride and finasteride inhibit type 2 5α-reductase, the dominant form of 5α-reductase in benign prostatic tissue, making these effective treatments for BPH. In comparison with finasteride, dutasteride has a longer half-life and leads to a greater and more consistent suppression of serum and intraprostatic DHT. EPICS is currently the only prospective, randomized, double-blind study of finasteride vs dutasteride for BPH endpoints conducted for longer than a few months. Over a one-year period, treatment with dutasteride and finasteride led to similar reductions in prostate volume, and improvements in peak urine flow and urinary symptoms associated with BPH in men with an enlarged prostate. Men treated with finasteride and dutasteride also experienced similar rates of adverse events over the course of one year, which suggests that inhibition of both type 1 and type 2 5α-reductase, resulting in greater DHT suppression than type 2 inhibition alone, does not confer an increase in adverse events. Given the long-term, progressive nature of BPH, the one-year duration of EPICS may limit the potential to observe major differences between dutasteride and finasteride treatment. OBJECTIVE • To assess the efficacy and safety of dutasteride compared with finasteride in treating men with symptomatic benign prostatic hyperplasia (BPH) for 12 months. PATIENTS AND METHODS • The Enlarged Prostate International Comparator Study was a multicentre, randomized, double-blind, 12-month, parallel-group study. • Men aged ≥50 years with a clinical diagnosis of BPH received once-daily treatment with dutasteride 0.5 mg (n= 813) or finasteride 5 mg (n= 817). After a 4-week placebo run-in period, patients were randomized to receive dutasteride or finasteride for 48 weeks, followed by an optional 24-month, open-label phase, during which patients received dutasteride 0.5 mg once daily. • The primary endpoint was change in prostate volume, and the secondary endpoints included improvement in American Urological Association Symptom Index (AUA-SI) scores, improvement in maximum urinary flow rate (Qmax) and long-term safety in the 24-month open-label phase. RESULTS • Both dutasteride and finasteride were effective at reducing prostate volume with no significant difference between the two treatments during the study. • Similar reductions in mean AUA-SI scores and Qmax were also observed for men in both treatment groups. • A similar percentage of adverse events was experienced by patients of both treatment groups, and no new adverse events were reported in the open-label phase. CONCLUSION • Dutasteride and finasteride, when administered for 12 months, were similarly effective in reducing prostate volume and improving Qmax and urinary symptoms associated with BPH in men with an enlarged prostate.