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Back to the forum  Query: 2017-12-13 08:32 CET (UTC+1h)
 
MaggieSantos
Junior

Portugal,
2017-09-20 13:05

Posting: # 17821
Views: 777
 

 Fampridine [Design Issues]

Good morning,

We have been asked to perform a BE study on Fampridine.

I would like to confirm two informations. Does Fampridine is considered a NTI drug for EMA?

Considering a CI limit of 90-111% whats the recomende sample size for fampridine.

Do you know any good and free calculation site for BE?

Kind Regards

mMrgarida Barreto
DavidManteigas
Regular

Portugal,
2017-09-26 10:55

@ MaggieSantos
Posting: # 17827
Views: 521
 

 Fampridine

Hi Margarida,

To calculate the sample size, you have the R package PowerTOST developed and mantained by some known members of this forum ;-)

Regarding the NTI status of Fampridine I can't help. If there is no information available, maybe you can ask directly to the agency you are targetting your submission?

Regards,
David Manteigas
ElMaestro
Hero

Denmark,
2017-09-26 11:23

@ MaggieSantos
Posting: # 17828
Views: 505
 

 Fampridine

Hi MaggieSantos,

» I would like to confirm two informations. Does Fampridine is considered a NTI drug for EMA?

Not known.

» Considering a CI limit of 90-111% whats the recomende sample size for fampridine.

You need a guess of your match (T/R) and your CV's. The latter can perhaps be guesstimated from this link.

» Do you know any good and free calculation site for BE?

Free? As in "free and unvalidated"? Do you mean Calculation of BE = calculation of confidence intervals or sample sizes or CV's? Or somehting else? At any rate forum.bebac.at is a good place to start for free services, ideas and pretty bad jokes.:-D:ok:

I agree with Manteigas - you really need dialogue with regulators on this type of substance; the profile is tricky and easily leads to safety concerns. When safety (and convulsions) is a manifest issue as worded in the SPC then some regulators may automatically default to NTI thinking.

But also note that originator did some equivalence trials and from the wording of FDA's review indicates that 80.00%-125.00% was acceptable for (some of) those applications; this might be argumentation you could use in your future scientific advices or presub meetings with regulators?

Having said that, considering the safety profile of the drug and the fact that you sound like you are developing or testing your own new formulation I think you should go for a phase I / pilot where subjects are monitored a bit more intensely than usual, and then define the dual purpose as:
a. ensuring that your formulation is associated with a relevant safety profile
b. extracting relevant CV's that will allow you to do a sample size calculation for your own formulation.

Good luck.

I could be wrong, but…


Best regards,
ElMaestro

A potentially biased estimator may be a relevant estimator. The case of REML speaks volumes.
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