Seamless phase IIa/IIb adaptive design with the same primary endpoint for proof of concept and dose finding.

This paper considers combining a proof of concept (POC) study and a dose finding (DF) study where the POC and the DF share the same primary endpoint. An example based on real study conditions shows that compared to a conventional design the proposed adaptive design tests more active doses, with a smaller sample size and a shorter overall duration leading to a budget saving of 30% in study operations.

A multicenter, randomized, double-blind, placebo controlled study of onabotulinumtoxinA 200 U to treat lower urinary tract symptoms in men with benign prostatic hyperplasia.

PURPOSE: We assessed the efficacy and tolerability of onabotulinumtoxinA 200 U vs placebo to treat lower urinary tract symptoms/benign prostatic hyperplasia in men previously treated with oral benign prostatic hyperplasia medication in a 24-week phase 2, multicenter, double-blind, randomized, placebo controlled, parallel group trial. MATERIALS AND METHODS: Patients with I-PSS (International Prostate Symptom Score) 14 or greater, peak urinary flow rate 4 to 15 ml per second and total prostate volume 30 to 80 ml were randomized 1:1 to a single intraprostatic treatment of onabotulinumtoxinA 200 U or placebo. A single-blind sham procedure followed by a 4-week run-in was included to attempt to minimize any potential placebo effect. Patients who still met eligibility criteria after the run-in entered the double-blind active treatment period. The primary end point was the change from baseline in total I-PSS at week 12. Other end points assessed at weeks 6, 12 and 24 included the change from baseline in total I-PSS, peak urinary flow rate, total prostate volume and post-void residual urine volume. RESULTS: Of 427 patients enrolled 315 were randomized and treated. Decreases from baseline in I-PSS were observed in the onabotulinumtoxinA and placebo groups (-6.3 vs -5.6 points, p <0.001) with no difference between the groups overall or in subgroups. Improvement was observed in the peak urinary flow rate, which was significant only at week 6 compared to placebo. Improvement was significant at all time points in a patient subgroup on stable concurrent α-blockers or 5α-reductase inhibitors during the study. Adverse events were similar in the 2 treatment groups. CONCLUSIONS: OnabotulinumtoxinA 200 U and placebo improved I-PSS and were well tolerated but no between group difference in efficacy was observed.

A randomized double-blind placebo-controlled phase 2 dose-ranging study of onabotulinumtoxinA in men with benign prostatic hyperplasia.

BACKGROUND: Botulinum toxin treatment has been investigated as a minimally invasive alternative to oral medications in men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (LUTS/BPH). OBJECTIVE: To explore the efficacy of onabotulinumtoxinA 100 U, 200 U, and 300 U versus placebo in men with LUTS/BPH in a phase 2 dose-ranging study. DESIGN, SETTING, AND PARTICIPANTS: A multicenter double-blind randomized, placebo-controlled 72-wk study enrolled men ≥ 50 yr of age with LUTS/BPH, International Prostate Symptom Score (IPSS) ≥ 12, total prostate volume (TPV) 30-100ml, and maximum flow rate (Q(max)) 5-15 ml/s. INTERVENTION: Single transperineal (n=63) or transrectal (n=311) administration of placebo (n=94) or onabotulinumtoxinA 100 U (n=95), 200 U (n=94), or 300 U (n=97) into the prostate transition zone. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary efficacy end point was a change from baseline in IPSS at week 12. Secondary end points were Q(max), TPV, and transition zone volume (TZV). Analysis of covariance and the Cochran-Mantel-Haenszel method assessed the efficacy and proportion of IPSS responders. Adverse events (AEs) were assessed. RESULTS AND LIMITATIONS: Significant improvements from baseline in IPSS, Q(max), TPV, and TZV were observed for all groups, including placebo, at week 12 (p<0.001), with no significant differences between onabotulinumtoxinA and placebo. However, in an exploratory post hoc analysis, a significant reduction in IPSS versus placebo was observed with onabotulinumtoxinA 200 U in prior α-blocker users (n=180) at week 12. AEs were comparable across all groups. CONCLUSIONS: Reductions in LUTS/BPH symptoms were seen in all groups, including placebo, with no significant between-group differences owing to a large placebo effect from the injectable therapy. The findings from the post hoc analysis in men previously treated with α-blockers will be further explored in an appropriately designed study. TRIAL REGISTRATION: http://www.Clinical Trials.gov; NCT00284518.