Hi Sébastien, My understanding is that keeping all thetas additive makes mu r referencing more efficient. The underlying mu reference math is then accurate for matrix linear formulations.
My understanding is not perfect for this, so I'll defer to others if there is a different answer. Thanks, Bill On Wed, Aug 23, 2023, 8:11 AM Sébastien Bihorel < sebastien.biho...@regeneron.com> wrote: > Hi > > Training material distributed during an ICON training contains the > following verbatim statements about mu referencing > > " > Code already defined as Typical Value (TV), actual value (as recommended > by Beal) are easy to convert: > – TVCL = THETA(1)*AGE**THETA(2) > – MU_5 = LOG(TVCL) > – CL = EXP(MU_5+ETA(5)) > > Even better, linear relationship of all THETAS with MU’s: > – LTVCL = THETA(1) + THETA(2)*LOG(AGE) > – MU_5 = LTVCL > – CL = EXP(MU_5+ETA(5)) > " > > Can someone comment on why the second parameterization is "even better ? > (besides the fact that estimates don't need to be bound) > > Thanks > > Sebastien Bihorel > ******************************************************************** > This e-mail and any attachment hereto, is intended only for use by the > addressee(s) named above and may contain legally privileged and/or > confidential information. If you are not the intended recipient of this > e-mail, any dissemination, distribution or copying of this email, or any > attachment hereto, is strictly prohibited. If you receive this email in > error please immediately notify me by return electronic mail and > permanently delete this email and any attachment hereto, any copy of this > e-mail and of any such attachment, and any printout thereof. Finally, > please note that only authorized representatives of Regeneron > Pharmaceuticals, Inc. have the power and authority to enter into business > dealings with any third party. > ******************************************************************** >
