Bioequivalence and Bioavailability Forum

Power for Two stage Design [Two-Stage / GS Designs]

posted by Helmut  – Vienna, Austria, 2013-10-07 16:59 (4647 d 16:03 ago) – Posting: # 11620
Views: 23,223

Hi Karthik,

❝ How to calculate Power for Two stage Design.

Not sure what you exactly want.
In the published frameworks power is fixed (Potvin et al. and Montague et al. 80%, Fuglsang 90%). With the exception of combinations of small stage 1 sample sizes and high CVs actual power exceeds these values (see this slide for Potvin’s Method B).
Or do you want to perform your own simulations?* Tough job. Simulate at least 10⁵ BE-studies in a grid of N₁ and CV with your target GMR. Empiric power = number of studies passing / number of simulations. Depending on the software / grid size expect run-times of a couple of hours to a few weeks…

---

• If you want to use a combination of GMR and target power which is not published yet, you have to demonstrate no substantial inflation of the patient’s risk, i.e., you have to find a suitable α_adj. Simulate with a GMR = one of the borders of the acceptance range. Since the convergence is slow (see this post) you have to simulate 10⁶ studies at each grid point.
  Hints:
  Method B ⇒ Method C: α_adj ↓ (= wider CI)
  Target power ↑: α_adj ↓
  GMR moving away from 1: α_adj ↓

—
Dif-tor heh smusma 🖖🏼 Довге життя Україна! 
Helmut Schütz


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Complete thread:

• Potvin’s 2-stage adaptive design GSD 2012-08-17 20:56 [Two-Stage / GS Designs] 
  • Potvin’s 2-stage adaptive design + RSABE/ABEL Helmut 2012-08-18 00:39
    • Potvin’s 2-stage adaptive design + RSABE/ABEL GSD 2012-08-31 16:30
      • Tough job Helmut 2012-08-31 18:37
        • Tough job GSD 2012-08-31 19:23
          • C/D for EMA? Good luck! Helmut 2012-09-01 15:09
        • Surprise? d_labes 2012-09-05 12:57
          • Got it. Ages for sims to complete Helmut 2012-09-05 13:35
            • Life belt d_labes 2012-09-05 14:51
              • Life belt Helmut 2012-09-05 15:20
    • Power for Two stage Design K2K 2013-10-07 14:43
      • Power for Two stage DesignHelmut 2013-10-07 14:59
        • Power for Two stage Design K2K 2013-10-08 14:35
          • “Interim power” Helmut 2013-10-08 14:58
            • “Interim power” K2K 2013-10-09 12:39
              • Validation of PowerTOST Helmut 2013-10-09 14:10
              • Phoenix/WinNonlin - power d_labes 2013-10-09 16:11
                • Phoenix/WinNonlin - power Helmut 2013-10-09 18:19
                  • power K2K 2013-10-10 08:36