Proposed changes [Two-Stage / GS Designs]

posted by Helmut Homepage – Vienna, Austria, 2020-02-17 14:16 (824 d 19:20 ago) – Posting: # 21178
Views: 4,406

Hi Mauricio,

» Instead of: "Type I error must be preserved and adjusted, and to demonstrate bioequivalence the level of confidence is 94.12%;"
»
» I will only propose that: It must be demonstrated that the type I error of the study is controlled.

OK in principle. It’s always a good idea not only to propose a change but give a justification. Maybe refer to the EMA’s and the WHO’s guidelines stating that the adjusted α has to be specified in the protocol and the choice is at the company’s discretion. α 0.0294 (i.e., the 94.12% CI) is definitely not the only possible one.

» Instead of: "This second group must have at least 50% of the previous group"
»
» I will propose that: The number of participants in the second stage must be calculated based on the data extracted from the first stage. The calculation must be justified considering possible losses and / or dropouts observed in the first stage.

OK. Do me a favor: Use estimated/estimation instead of calculated/calculation. ;-)
Of course, n2 is always based on the eligible subjects in the interim (n1), not on the subjects randomized.
Justification: A minimum stage 2 sample size is not covered by the published methods; any minimum n2 might inflate the Type I Error. If that sounds too statistical write “the patient’s risk” instead.

Dif-tor heh smusma 🖖 [image]
Helmut Schütz
[image]

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

Complete thread:

UA Flag
Activity
 Admin contact
22,091 posts in 4,630 threads, 1,566 registered users;
online 11 (0 registered, 11 guests [including 8 identified bots]).
Forum time: Sunday 10:36 CEST (Europe/Vienna)

Competence, like truth, beauty and contact lenses,
is in the eye of the beholder.    Laurence J. Peter

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5