Fixed dose inappropriate

However, if the use of a placebo is impractical, or inappropriate for ethical or technical reasons, a multiple fixed-dose study without a placebo arm may be an acceptable option. This approach involves comparison of responses to a range of doses of the test drug in comparison with a standard compound. When significant differences between treatment groups are observed, some positive conclusions regarding efficacy can be derived from the data. However, a multiple fixed-dose study design also has some disadvantages ... 

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