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Planned versus attained design in phase II clinical trials
Author(s) -
Green Stephanie J.,
Dahlberg Steve
Publication year - 1992
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4780110703
Subject(s) - sample size determination , variety (cybernetics) , phase (matter) , computer science , null hypothesis , statistics , multi stage , multiple comparisons problem , mathematics , chemistry , organic chemistry , process engineering , engineering
The standard phase II trial problem is to decide whether or not to continue the testing of a new agent (or combination). Typically, one tests the null hypothesis H o : p = p o against the alternative H A : p = p A , where p is the probability of response. There is available a variety of two‐stage phase II designs, including optimal designs according to various criteria. Practical considerations in the conduct of multicentre trials, however, make it difficult to follow designs precisely. We investigate several approaches to adapting stopping rules when the attained sample size is not the planned size. We find that a simple approach of testing H A : p = p A at the 0·02 level at the first stage and H o : p = p o at the 0·055 level at the second stage works well across a variety of powers, p o s and p A s .