Dipesh Jayswal ● 2007-03-13 11:38 (6226 d 04:52 ago) Posting: # 573 Views: 6,589 |
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Dear HS, I have two questions regarding sample size determination for BE study: 1. is it possible to estimate sample size for 2way crossover from parallel BE study???? 2. Assume that we have a data for 3way crossover(3 period - 6 sequence) pilot - BE study in which two test products(T1 and T2) were compared with RLD. Now we want to go ahead with either of the test formulation (i.e. either T1 or T2) to be compared with RLD in 2way crossover(2 period - 2 sequence) pivotal study, then how to estimate the correct Sample Size for it??? please suggest me way out or some reading on it???? Thanks in advance. Dipesh |
Helmut ★★★ Vienna, Austria, 2007-03-13 13:50 (6226 d 02:40 ago) @ Dipesh Jayswal Posting: # 574 Views: 5,444 |
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Dear Dipesh! ❝ 1. is it possible to estimate sample size for 2way crossover from parallel ❝ BE study???? No! From a parallel study you only get information on the total variability (= between and within, or inter- and intra- subject); there is no way to extract the intra-subject CV from this kind of study. One thing is granted: CV-intra < CV-total For some drugs CV-total is >50%, but CV-intra <10%... ❝ 2. Assume that we have a data for 3way crossover(3 period - 6 sequence) ❝ pilot - BE study in which two test products(T1 and T2) were compared with ❝ RLD. Now we want to go ahead with either of the test formulation (i.e. ❝ either T1 or T2) to be compared with RLD in 2way crossover(2 period - 2 ❝ sequence) pivotal study, then how to estimate the correct Sample Size for ❝ it??? It's quite reasonable to apply the CV-intra from the 3×6 study in sample size estimation for the pivotal 2×2. ❝ please suggest me way out or some reading on it???? S-C Chow and J-p Liu Design and Analysis of Bioavailability and Bioequivalence Studies Marcel Dekker, New York, 2nd Ed. (2000) S Patterson and B Jones Bioequivalence and Statistics in Clinical Pharmacology Chapman & Hall, Boca Raton (2006) D Hauschke, V Steinijans and I Pigeot Bioequivalence Studies in Drug Development - Methods and Applications John Wiley & Sons, Chichester (2007) — Dif-tor heh smusma 🖖🏼 Довге життя Україна! Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
Dipesh Jayswal ● 2007-03-13 14:31 (6226 d 01:59 ago) @ Helmut Posting: # 575 Views: 5,323 |
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Thanks a lot HS for ur reply.. i know that from total variability it is not possible to separate out the intra CV as u suggested. Thanks for ur confirmation. regarding intra CV% from 3way crossover BE study, it is the mixture of all the the three formulations. I wanted to know that is it possible to estimate intra CV for RLD and either T1 or T2. thak u again for ur prompt reply. Regards, Dipesh Edit: Full quote removed. [HS] |
Helmut ★★★ Vienna, Austria, 2007-03-13 14:43 (6226 d 01:47 ago) @ Dipesh Jayswal Posting: # 576 Views: 5,457 |
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Dear Dipesh! ❝ regarding intra CV% from 3way crossover BE study, it is the mixture of all ❝ the the three formulations. I wanted to know that is it possible to ❝ estimate intra CV for RLD and either T1 or T2. It's not possible to obtain the variability of treatments for a 3×6 design (as it's not possible for a 2×2 design), since you have administered each of the 3 formulations only once. In order to get information on the variability of formulations, a replicate design is needed. — Dif-tor heh smusma 🖖🏼 Довге життя Україна! Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
Dipesh Jayswal ● 2007-03-14 09:08 (6225 d 07:22 ago) (edited by HS on 2007-03-14 11:47) @ Helmut Posting: # 577 Views: 5,261 |
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Dear HS, Thanks for ur clarification. -- Edit: Full quote removed. [HS] |