Log in
RegisterNTIDs # HVDs (or not?) [Design Issues]
posted by Helmut 
– Vienna, Austria, 2010-06-07 16:18 (5339 d 05:55 ago) – Posting: # 5453
Views: 8,999
Dear Jo!
This is strange. NTIDs are generally not highly variable – otherwise they wouldn’t have ‘survived’ the MA in the first place.
Oops?! Can you give us the name of the drug?
Well…
If we are talking about immunosuppressants, we are talking about a study in patients, right? Steady state too. Likely parallel design – it’s unethical to interrupt treatment by a washout. The disease state may change between periods which will prevent a cross-over anyhow.
Even if you opt for a cross-over, a replicate design doesn’t help in the reducing the numbers of treatments applied (or in other words, the number of biosamples and study costs). If the 2×2 study size is 300, the size for a 4-period replicate is still 150, but expect more drop-outs and problems with the increased number of blood samples / subject.
❝ Which is the most appropriate design for a narrow therapeutic index drug with very high intra-subject variability?
This is strange. NTIDs are generally not highly variable – otherwise they wouldn’t have ‘survived’ the MA in the first place.
❝ For example, we have an immunosuppressive agent with an intra-subject CV% > 45%.
Oops?! Can you give us the name of the drug?
❝ Using a standard two – way crossover design with acceptance interval tightened (90.00 – 111.11%), we will have a sample size of more than 300 subjects 
.
Well…
❝ It is possible to use a replicate design in this situation?
If we are talking about immunosuppressants, we are talking about a study in patients, right? Steady state too. Likely parallel design – it’s unethical to interrupt treatment by a washout. The disease state may change between periods which will prevent a cross-over anyhow.
Even if you opt for a cross-over, a replicate design doesn’t help in the reducing the numbers of treatments applied (or in other words, the number of biosamples and study costs). If the 2×2 study size is 300, the size for a 4-period replicate is still 150, but expect more drop-outs and problems with the increased number of blood samples / subject.
—
Dif-tor heh smusma 🖖🏼 Довге життя Україна!![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
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
Complete thread:
- NTIDs with high variability ioanam 2010-06-07 13:52 [Design Issues]
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- NTIDs # HVDs (or not?)Helmut 2010-06-07 14:18
- NTIDs # HVDs (or not?) ioanam 2010-06-07 18:17
- Complicated ElMaestro 2010-06-07 18:28
- NTIDs # HVDs (or not?) Dr_Dan 2010-06-08 12:24
- Switch over Helmut 2010-06-08 12:34
- NTIDs # HVDs (or not?) Relaxation 2010-06-09 22:38
- FDA scaling for NTIDs krishna 2013-01-07 14:01
- FDA scaling for NTIDs Helmut 2013-01-12 20:06
- FDA scaling for NTIDs krishna 2013-01-18 10:04
- FDA scaling for NTIDs Helmut 2013-01-20 12:46
- FDA scaling for NTIDs krishna 2013-02-01 12:20
- FDA scaling for NTIDs Helmut 2013-01-20 12:46
- FDA scaling for NTIDs krishna 2013-01-18 10:04
- FDA scaling for NTIDs Helmut 2013-01-12 20:06
- FDA scaling for NTIDs krishna 2013-01-07 14:01
- NTIDs # HVDs (or not?) Relaxation 2010-06-09 22:38
- Switch over Helmut 2010-06-08 12:34
- NTIDs # HVDs (or not?) ioanam 2010-06-07 18:17
- NTIDs # HVDs (or not?)Helmut 2010-06-07 14:18
Ing. Helmut Schütz