Mikalai
★

Belarus,
2019-12-14 14:39

Posting: # 20975
Views: 1,198

## NTI drug but with high CV [Power / Sample Size]

Dear all.
What would be a sample size for a BE study when the CV of the drug is 30% but bioequivalence should be in range 90_110%? Our assumption is around 400 subject if the design is standard, and 200 if the design is replicative
Best regards.
Helmut
★★★

Vienna, Austria,
2019-12-14 15:11

@ Mikalai
Posting: # 20976
Views: 806

## NTI drug with high CV?

Hi Mikalai,

» What would be a sample size for a BE study when the CV of the drug is 30% but bioequivalence should be in range 90_110%?

Unless the drug belongs to the last generation anticoagulants (dabigatran, rivaroxaban) that's a contradiction. NTIDs show low variability. Otherwise, there would have been serious problems in phase III: toxicity, lacking efficacy – no approval – end of story.
BTW, the acceptance limits for NTIDs in the EEA are 90.00–111.11%.

» Our assumption is around 400 subject if the design is standard, and 200 if the design is replicative

library(PowerTOST) sampleN.TOST(CV = 0.3, theta1 = 0.9, design = "2x2x2") sampleN.TOST(CV = 0.3, theta1 = 0.9, design = "2x2x4")

Dif-tor heh smusma 🖖
Helmut Schütz

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