RE: [NMusers] RE: re: bug in NONMEM VI?

I'd also like to see how correlated COV3 and COV4 are. This may be a
collinearity issue.
 
pete bonate
 
Peter L. Bonate, PhD, FCP
Genzyme Corporation
Senior Director
Clinical Pharmacology and Pharmacokinetics
4545 Horizon Hill Blvd
San Antonio, TX 78229 USA
peter.bonate_at_genzyme.com
phone: 210-949-8662
fax: 210-949-8219
crackberry: 210-315-2713
 

________________________________

From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com]
On Behalf Of Bill Bachman
Sent: Wednesday, January 02, 2008 2:38 PM
To: 'John Lukas'; nmusers_at_globomaxnm.com
Subject: RE: [NMusers] RE: re: bug in NONMEM VI?



Have you tried both of these runs using the SLOW option on the
estimation record?

 

________________________________

From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com]
On Behalf Of John Lukas
Sent: Wednesday, January 02, 2008 2:36 PM
To: nmusers_at_globomaxnm.com
Subject: [NMusers] RE: re: bug in NONMEM VI?

 

 

 

________________________________

From: John Lukas
Sent: Mon 12/17/2007 11:51 PM
To: nmusers_at_globomaxnm.com
Subject: re: bug in NONMEM VI?

Dear Nmusers,

 

A simple LME model run using NM version VI, FO method, with 4 covariates
(5 THETA's) as,

.

.

$PRED

 

SUM1=THETA(2)*COV1+THETA(3)*COV2

SUM2=THETA(4)*COV4+THETA(5)*COV3

 

TLAU=THETA(1)+SUM1+SUM2

F=TLAU+ETA(1)

 

Y=F+EPS(1)

 

$THETA 4 .1 .1 .1 .1

$OMEGA .1

$SIGMA .1

 

$ESTIMATION MAXEVALS=1900 PRINT=5 METHOD=0

 

(let's call this FIT A) gave a different fit from another (FIT B) where
only the order of THETA( 4) and 5 was reversed, all else kept the same,
as,

.

.

SUM2=THETA(5)*COV4+THETA(4)*COV3

.

.

(even more strange, FIT B, the reversed order run, proved to be the good
run!)

 

NONMEM version V had the same result for both FITS A and B, as expected
(and same as FIT B from version 6). FOCE gave good answers always in
both NONMEM version V and version VI. But, the question remains about
that dependence on ordering of the THETAs with the FO method for version
VI.

 

Any comments? Has there been discussion on this earlier that I missed?
Thanks in advance.

 

John

PS I am aware of other *important* incosistencies between version VI and
V from university colleagues working on a PK problem with FOCE...

 

 

John C Lukas

Strategic Consulting Services

Pharsight Corp.

 

line: + 33 492 726 495

cell: + 33 626 496 777

 

 


Received on Wed Jan 02 2008 - 16:03:36 EST