Ing. Helmut Schütz

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Articles

This series of articles was inspired by recurrent discussions at the Bio­equi­va­lence and Bio­avail­ability Forum and questions I received from regulatory assessors or my clients.

The content expressed in the articles presents my sole personal opinion. Although regulatory requirements are incorporated to a high degree, some strong views are strictly scientifically based on my 40 years of experience in the field and do not represent any type of “cookbook approach” which should be followed unreflecting.
I do not make any representations or warranties regarding the accuracy of such content.

To the right articles are listed in chronological order. Below are articles arranged by topic.

• 🃏 Related to questions commonly asked by regulatory assessors.
• 🆕 Published within the last two weeks.
• 🚧 Article under construction.

To reproduce the articles’ examples is required.

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Power Calculation and Sample Size Estimation

Equivalence

• Parallel Design 291 KB (update 2022-01-14)
• 2×2×2 Design 353 KB (update 2022-01-14)
• Higher-Order Crossover Designs 219 KB (update 2021-12-15)
• Replicate Designs
  • Average Bioequivalence 177 KB (update 2022-01-23)
  • Scaled Average Bioequivalence
    • Highly Variable Drugs / Drug Products
      • RSABE (FDA, China’s CDE) 152 KB (update 2022-01-01)
      • ABEL (all others) 163 KB (update 2022-01-01)
    • Narrow Therapeutic Index Drugs (FDA) 156 KB (update 2022-01-25)
    • Highly Variable Narrow Therapeutic Index Drugs (FDA) 🚧
  • ABE, RSABE, ABEL – A Comparison 279 KB (update 2022-01-22)
• Two-Stage Designs
  • Group sequential (fixed sample design) 🚧
  • Adaptive (sample size re-estimation) 🃏 🚧

Non-Inferiority, Non-Superiority

• Non-Inferiority 🚧
• Non-Superiority 🚧

Dose Proportionality 🚧

Prospective Power

• Power Analysis 52 KB (update 2021-12-05)
• Sensitivity Analysis 239 KB (update 2022-01-02)
• Overall Power of Multiple Studies 🚧

Noncompartmental Analysis

• Trapezoidal Rules 174 KB (update 2021-12-23)
• Estimation of λ_z 🚧
• Demonstration of Steady State Achievement? 🆕 148 KB (update 2022-01-22)
• Partial AUC 🚧
• Cut-off Times for Biphasic Release Products 🚧
• C_min and C_τ 🚧

Miscellaneous

Statistics

• A Short History of Bioequivalence 🚧
• Carryover – A Never Ending Story 251 KB (update 2022-01-02) 🃏
• Significant Treatment Effect 121 KB (update 2021-11-27) 🃏
• Fixed or mixed effects? 🚧
• Group ‘Effect’: To Pool or Not to Pool? 🃏 🚧
• Post hoc Power 149 KB (update 2021-12-05) 🃏
• ‘Apparent’ Difference in t_max? 129 KB (update 2021-04-22)
• Inflation of the Type I Error in SABE 🚧
• Simulations 101 192 KB (update 2022-01-23)
• ‘Nice Numbers’ – A Rant 99 KB (update 2022-01-05)
• ‘Precise’ Numbers in Reports 🚧
• Subgroup Analyses 🚧
• Adjusted Indirect Comparisons 🚧

Design Issues

• Washout Phase – Tricks and Traps 🃏 🚧
• Pilot → Pivotal Studies 🚧
• SABE planned based on the CV_w of a 2×2×2 Crossover Design 🚧
• Stratified Randomization – Why? 🚧

Software

• Representing Numbers in Computers – A Wonderland 113 KB (update 2022-01-12)
• 🇷 on Windows 101 46 KB (update 2022-01-12)
• Software Validation 🚧

All articles are licensed under Creative Commons Attribution 4.0 Helmut Schütz 2022.