Objectives: To demonstrate non-inferiority of an herbal combination (horseradish root and nasturtium herb) to an antibiotic (co-trimoxazole) in acute uncomplicated cystitis.
Design: Randomized, prospective, double-blind, double-dummy, multicenter, phase III clinical study, using block randomization of 4 blocks (size 2).
Setting: Twenty-six centers in Germany, from May 2011 to June 2013.
Participants: Adult patients (median age, 38.5 years; 90% female) with acute uncomplicated cystitis confirmed via urinalysis and bacterial counts.
Interventions: Patients received the herbal combination (five tablets, four times per day) or the antibiotic (two tablets daily) for a period of 7 or 3 days, respectively, followed by a 21-days without drug treatment. Placebos ensured blinding.
Primary and secondary outcome measures: The primary endpoint was the percentage of responders, expressed as reduction of germ count from >105 to <103 CFU/mL of pathogens between visit 1 (day 0) and 3 (day 15). Secondary endpoints included change of symptom scores, duration of symptoms, efficacy assessments, relapse frequency, and safety. A sample size of 178 patients per group was estimated.
Results: Of the 96 randomized patients (intent-to-treat; 45 in the phytotherapy group, 51 in the antibiotic group), 51 were considered per-protocol patients (22 in the phytotherapy group, 29 in the antibiotic group). Responder rates were 10/22 (45.5%) for the phytotherapy group and 15/29 (51.1%) for the antibiotic group (group difference: -6.27% [95% CI: -33.90%-21.3%]). The study was terminated prematurely due to slow recruitment rates. Non-inferiority could not be assumed by predefined criteria. During the follow-up period, one relapse occurred in each group. Both treatments were well tolerated.
Conclusion: This clinical trial indicates comparable efficacy of the herbal combination and antibiotic, although non-inferiority was not proved. However, the results and lessons learned are important for the planning of future trials. Issues that led to the premature trial discontinuation were considered.
Keywords: co-trimoxazole; cystitis; herbal medicinal product; horseradish; nasturtium herb; randomized clinical trial; urinary tract infection.