Study costs: Replicate vs. 2×2×2 [Regulatives / Guidelines]
❝ ❝ My concensus still would be to proceed with RSABE approach since the it is a mixed approach which allows both RSABE(if Ref SD<0.294) and ABE analysis(if Ref SD>0.294)
❝ That's valid, but if you are not really sure if you are just "borderline" then the additional overhead associated with the replicated design may not be worth it. You find an intra-CVR of 31%, and you scale the limits a wee bit etc. But the price you paid for this moderate scaling option could be much higher than you'd be paying for a conventional 222BE trial with a few extra volunteers.
I lean towards John’s idea. Say you estimated the 31% from a previous 2×2×2 study in 40 subjects and assume that CVwR=CVwT=CVw. The 95% CI of the CV is 25.1–40.6%. Hence, in the best case (high CVwR) the FDA’s implied BE-limits would be 70.58–141.69%. That’s rather substantial.
❝ Would be interesting to discuss an objective function here
Some ideas: The number of treatments in a 2×2×4 study is roughly the same as in a 2×2×2 study – if we don’t plan for reference-scaling (which I likely would do in a borderline case).
- Equal costs
- Design & logistics,
- Ethics committee,
- Medical writing,
- Consumables (clinics, bioanalytics),
- Sample shipment if applicable,
- Biostatistics.
- Screenings & post-study exams,
- Subjects’ remuneration (though higher for the individuals due to more samples, extended hospitalization).
- Clinics,
- Analytics (not necessarily: Roughly the same number of samples but might take longer if a batch size exceeds a working day).
Calculation of costs is complicated (fixed & variable costs, blahblah). In my CRO we had a spreadsheet with 100 rows… Had a quick look (19 samples / period, last sampling 16 hours; 2×2×2 in 42 subjects vs. 2×2×4 in 22). The replicate design would be ~4% cheaper.

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
Complete thread:
- Highly Variable Drug BE Justification jag009 2017-03-20 04:42 [Regulatives / Guidelines]
- Highly Variable Drug BE Justification ElMaestro 2017-03-20 06:55
- Study costs: Replicate vs. 2×2×2Helmut 2017-03-20 13:12
- Study costs: Replicate seems to be cheaper VStus 2017-03-21 12:49
- Study costs: Replicate seems to be cheaper Dr_Dan 2017-03-21 13:06
- Study costs: Replicate seems to be cheaper Helmut 2017-03-21 14:50
- expected power d_labes 2017-03-21 15:16
- Doesn't hurt! VStus 2017-03-23 14:24
- Study costs: Replicate seems to be cheaper Helmut 2017-03-21 14:50
- Study costs: Replicate seems to be cheaper Dr_Dan 2017-03-21 13:06
- Study costs: Replicate vs. 2×2×2 mahmoud-teaima 2017-03-23 08:17
- Study costs: Replicate vs. 2×2×2 M.tareq 2017-05-07 21:21
- Replicate vs. 2×2×2 (ethics?) Helmut 2017-05-08 14:21
- Replicate vs. 2×2×2 (ethics?) nobody 2017-05-08 14:52
- Applicability of reference-scaling Helmut 2017-05-10 14:10
- Replicate vs. 2×2×2 M.tareq 2017-05-14 23:04
- Replicate vs. 2×2×2 Helmut 2017-05-15 19:07
- Replicate vs. 2×2×2 M.tareq 2017-05-15 21:02
- Regulators view of HVD drugs DavidManteigas 2017-05-16 12:41
- Regulators view of HVD drugs Helmut 2017-05-16 15:01
- What's the problem? ElMaestro 2017-05-17 03:30
- What's the problem? nobody 2017-05-17 07:48
- What's the problem? nobody 2017-05-17 09:31
- What's the problem? DavidManteigas 2017-05-17 11:25
- What's the problem? ElMaestro 2017-05-17 12:07
- What's the problem? kumarnaidu 2017-07-11 14:43
- What's the problem? ElMaestro 2017-07-11 14:56
- What's the problem? kumarnaidu 2017-07-11 14:43
- What's the problem? ElMaestro 2017-05-17 12:07
- What's the problem? DavidManteigas 2017-05-17 11:25
- What's the problem? nobody 2017-05-17 09:31
- What's the problem? nobody 2017-05-17 07:48
- Replicate vs. 2×2×2 Helmut 2017-05-15 19:07
- Replicate vs. 2×2×2 (ethics?) nobody 2017-05-08 14:52
- Replicate vs. 2×2×2 (ethics?) Helmut 2017-05-08 14:21
- Study costs: Replicate seems to be cheaper VStus 2017-03-21 12:49
- Study costs: Replicate vs. 2×2×2Helmut 2017-03-20 13:12
- Highly Variable Drug BE Justification ElMaestro 2017-03-20 06:55