A systematic review of Cernilton for the treatment of benign prostatic hyperplasia

Objective. To systematically review the evidence for the clinical effects and safety of the rye-grass pollen extract (Cernilton) in men with symptomatic benign prostatic hyperplasia (BPH). Methods. Trials were identified by searching Medline, specialized databases (EMBASE, Cochrane Library, Phytodok), bibliographies, and contacting relevant trialists and manufacturers. Randomized or controlled clinical trials were included if: men with symptomatic BPH were treated with Cernilton: a control group received either placebo or pharmacological therapy; the treatment duration was ≥ 30 days; and clinical outcomes were reported. Results. In all, 444 men were enrolled in two placebo-controlled and two comparative trials lasting 12-24 weeks. Three studies used a double-blind method although the concealment of treatment allocation was unclear in all. Cernilton improved 'self-rated urinary symptoms' (the proportion reporting satisfactory or improving symptoms) vs placebo and another plant product, Tadenan. The weighted mean (95% confidence interval) risk ratio (RR) for self-rated improvement vs placebo was 2.40 (1.21-4.75) and the weighted RR vs Tadenan was 1.42 (1.21-4.75). Cernilton reduced nocturia compared with placebo or Paraprost (a mixture of amino acids): against placebo, the weighted RR was 12.05 (1.41-3.00), and against Paraprost the weighted mean difference for nocturia was -0.40 times per evening (-0.73 to 0.07). Cernilton did not improve urinary flow rates, residual volume or prostate size compared with placebo or the comparative study agents. Adverse events were rare and mild: the withdrawal rate for Cernilton was 4.8%, compared with 2.7% for placebo and 5.2% for Parapost. Conclusions. The Cernilton trials analysed were limited by their short duration, limited number of enrolees, omissions in reported outcomes and the unknown quality of the preparations used. The comparative trials had no confirmed active control. The available evidence suggests that Cernilton is well tolerated and modestly improves overall urological symptoms, including nocturia. Additional randomized placebo and active-controlled trials are needed to evaluate the long-term clinical effectiveness and safety of Cernilton.