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Sriraj ☆ India, 2010-04-12 11:39 (5910 d 21:49 ago) Posting: # 5081 Views: 7,899 |
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Dear members, --> In phase-I trials, mostly we do exploratory studies. Suppose if are doing a food-effect study for new drug say 'drug a', since we are doing the study with food-effect for the first time we will not have any information regarding the intra CV. In such cases how to consider the intra CV for sample size calculation. --> If we are doing a Drug Drug Interaction study (DDI), period-I NCE, period-II NCE+CoAd. In such cases how to consider intra CV. We may have intra CV information of NCE from different study say NCE food-effect study, and we may have CoAd intra CV with another NCE. In such case which intra CV do we need to consider. CV which is coming from CoAd study or CV from NCE study? Many thanks in advance, SriKanth (SriRaj) |
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rasheed ☆ 2010-04-13 08:21 (5910 d 01:07 ago) (edited on 2010-04-13 11:58) @ Sriraj Posting: # 5101 Views: 7,125 |
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❝ --> In phase-I trials, mostly we do exploratory studies. Suppose if are doing ❝ a food-effect study for new drug say 'drug a', since we are doing the study ❝ with food-effect for the first time we will not have any information regarding ❝ the intra CV. In such cases how to consider the intra CV for sample size ❝ calculation. According to FDA recomendations, you can get CV from previous study or performing a pilot study. So if there is no information from previous study in case that no such study has been performed so the better idea is to perform a pilot study and obtained a CV that can reasonably used for the complete study. best regards rasheed. Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe] |
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Sriraj ☆ India, 2010-04-13 11:31 (5909 d 21:56 ago) (edited on 2010-04-13 12:00) @ rasheed Posting: # 5105 Views: 6,887 |
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Dear Rasheed, Thanks for the reply. According to your mail, we need to conduct a pilot study everytime before conducting the main study, which is not possible and increases cost. If we are performing an exploratory study we dont need to consider one pilot and one main study. Two studies with same design. According to my knowledge, if we are estimating the sample size for a food-effect study for DrugA, and if have information regarding the CV from another study where DrugA is administered as tablet and capsule formulation, then we can take that CV. But my question is this estimate of CV could not be a realistic one. Thank you, SriKanth Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe] |
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rasheed ☆ 2010-04-13 13:19 (5909 d 20:08 ago) @ Sriraj Posting: # 5106 Views: 6,871 |
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Dear Srikanth I mentioned that pilot study is the secondary preference, first one is previous study if it has been done, you no need to perform pilot study agian agian for each and every new complete study, e.g., you perform a pilot study for the complete study for drug A, once this completed has ended you this study would become a pervious one for every new study in which the similar formulation of Drug A has been administrated regards Rasheed Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe] |
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Ohlbe ★★★ France, 2010-04-13 14:05 (5909 d 19:22 ago) @ rasheed Posting: # 5107 Views: 6,857 |
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Dear Rasheed and Sriraj, When answering messages, please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! I had to edit your messages, which were just getting impossible to read. Remember also to use the Preview button, just next to the OK - Submit button, to see what your post will look like. Regards Ohlbe — Regards Ohlbe |
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rasheed ☆ 2010-04-13 14:25 (5909 d 19:03 ago) @ Ohlbe Posting: # 5108 Views: 6,777 |
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OK I understand try to do my best |
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Sriraj ☆ India, 2010-04-14 11:30 (5908 d 21:58 ago) @ rasheed Posting: # 5117 Views: 6,777 |
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Dear Rasheed, I am getting confused with this. My question is, suppose if we have CV% where Drug A with x dosage administered in tablet and capsule formulations from Study-1, and now if we are conducting a study (Study-2) with different design and with different dosage, say Study-2 is of food effect study with Drug A with y-dosage then can we use the CV% information from study-1 to evaluate the sample size for Study-2. Thank you, SriKanth |
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Dr_Dan ★★ Germany, 2010-04-14 12:24 (5908 d 21:04 ago) @ Sriraj Posting: # 5119 Views: 6,802 |
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Hi all to my understanding a CV% refers to the drug substance administered in a certain state (i.e. fed or fasted). In other words: the intra-subject variability can be complete different in a fasted state compared to the fed state of the subject. I guess in most cases the CV% is less higher in the fed state, right? Regards Dan — Kind regards and have a nice day Dr_Dan |
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Sriraj ☆ India, 2010-04-14 12:40 (5908 d 20:48 ago) @ Dr_Dan Posting: # 5121 Views: 6,851 |
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Dear Dan, Obviously the CV% would differ, but my question is- can we consider the intra CV% from Study-1 to evaluate the sample size for Study-2. Thank you, SriKanth (SriRaj) |
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rasheed ☆ 2010-04-14 14:35 (5908 d 18:53 ago) @ Sriraj Posting: # 5124 Views: 6,761 |
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Dear Yes u can, but drug should be the same for both study regardless of different dosage of drug for both studies regards rasheed |
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Ohlbe ★★★ France, 2010-04-14 17:32 (5908 d 15:55 ago) @ Sriraj Posting: # 5130 Views: 6,766 |
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Dear Sriraj, ❝ Obviously the CV% would differ, but my question is- can we consider the ❝ intra CV% from Study-1 to evaluate the sample size for Study-2. How do you plan to do it ? For example if you have an intra-CV of 25 % in the first study and you expect it to be higher in the second, what are you going to do ? You only know it will be more than 25 %, but you still don't know how much more, and therefore how many extra subjects you need. Rasheed, you're saying it is possible. Can you explain what your suggestion would be ? Regards Ohlbe — Regards Ohlbe |
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statistician ☆ India, 2010-09-27 16:51 (5742 d 16:36 ago) @ Sriraj Posting: # 5939 Views: 6,447 |
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❝ Dear all, kindly help me in this issue i neeed to know what are the criteria required for calculating sample size in pilot studies since i am finding difficulty in collecting the information regarding intra subject cv or other related articles regarding the drug kindly help me especially for highly variable sustained release drugs. Thank you, RK |
Ing. Helmut Schütz