Bioequivalence and Bioavailability Forum • Study costs: Replicate seems to be cheaper

Study costs: Replicate seems to be cheaper [Regulatives / Guidelines]

posted by Helmut – Vienna, Austria, 2017-03-21 15:50 (3023 d 19:13 ago) – Posting: # 17176
Views: 24,623

Hi Dan,

I agree with VStus.

❝ For your calculation please keep in mind: the more study periods you have the higher the risk of drop outs.

As I wrote above:

❝ ❝ I would not be worried about the higher chance of dropouts in the replicate study. The impact on power is low (unless the drug is nasty and dropouts are caused by AEs).

Try:

library(PowerTOST) CV <- 0.31 dor <- 5 # dropout-rate (in each washout) in percent des <- "2x2x2" res <- sampleN.TOST(CV=0.31, design=des, print=FALSE) n <- res[["Sample size"]] pwr <- res[["Achieved power"]] wo <- as.integer(substr(des, nchar(des), nchar(des)))-1 el <- n # eligible subjects for (j in 1:wo) { el <- el*(1-dor/100) } cat("Study started with", n, "subjects (expected power", sprintf("%.1f%%).", 100*pwr), "\nStudy ended with", as.integer(el), "eligible subjects (expected power", sprintf("%.1f%%).", 100*power.TOST(CV=CV, design=des, n=el)), "\n") # Study started with 42 subjects (expected power 81.1%). # Study ended with 39 eligible subjects (expected power 79.2%). des <- "2x2x4" res <- sampleN.TOST(CV=0.31, design=des, print=FALSE) n <- res[["Sample size"]] pwr <- res[["Achieved power"]] wo <- as.integer(substr(des, nchar(des), nchar(des)))-1 el <- n for (j in 1:wo) { el <- el*(1-dor/100) } cat("Study started with", n, "subjects (expected power", sprintf("%.1f%%).", 100*pwr), "\nStudy ended with", as.integer(el), "eligible subjects (expected power", sprintf("%.1f%%).", 100*power.TOST(CV=CV, design=des, n=el)), "\n") # Study started with 22 subjects (expected power 83.3%). # Study ended with 18 eligible subjects (expected power 75.1%).

Does it really hurt?

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

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

Highly Variable Drug BE Justification jag009 2017-03-20 04:42 [Regulatives / Guidelines]
- Highly Variable Drug BE Justification ElMaestro 2017-03-20 06:55
  - Study costs: Replicate vs. 2×2×2 Helmut 2017-03-20 13:12
    - Study costs: Replicate seems to be cheaper VStus 2017-03-21 12:49
      - Study costs: Replicate seems to be cheaper Dr_Dan 2017-03-21 13:06
        
        Study costs: Replicate seems to be cheaperHelmut 2017-03-21 14:50
        
        expected power d_labes 2017-03-21 15:16
        Doesn't hurt! VStus 2017-03-23 14:24
    - Study costs: Replicate vs. 2×2×2 mahmoud-teaima 2017-03-23 08:17
    - Study costs: Replicate vs. 2×2×2 M.tareq 2017-05-07 21:21
      - Replicate vs. 2×2×2 (ethics?) Helmut 2017-05-08 14:21
        
        Replicate vs. 2×2×2 (ethics?) nobody 2017-05-08 14:52
        
        Applicability of reference-scaling Helmut 2017-05-10 14:10
        
        Replicate vs. 2×2×2 M.tareq 2017-05-14 23:04
        
        Replicate vs. 2×2×2 Helmut 2017-05-15 19:07
        
        Replicate vs. 2×2×2 M.tareq 2017-05-15 21:02
        Regulators view of HVD drugs DavidManteigas 2017-05-16 12:41
        
        Regulators view of HVD drugs Helmut 2017-05-16 15:01
        What's the problem? ElMaestro 2017-05-17 03:30
        
        What's the problem? nobody 2017-05-17 07:48
        
        What's the problem? nobody 2017-05-17 09:31
        
        What's the problem? DavidManteigas 2017-05-17 11:25
        
        What's the problem? ElMaestro 2017-05-17 12:07
        
        What's the problem? kumarnaidu 2017-07-11 14:43
        
        What's the problem? ElMaestro 2017-07-11 14:56