RE: [NMusers] General question on modeling

nce we wish to draw from it. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com

RE: [NMusers] General question on modeling

Mark > But, I have to admit that I'm uncomfortable with the concept > of the "art" of modeling. I agree - I like to think of it as a science of modelling - but I have heard (at conferences) the "science" of modelling referred to as the "art" of modelling. > decisions on art? Shouldn't we be

RE: [NMusers] General question on modeling

tinuous and in oncology BSA is considered continuous. Certainly my approach to the clinical sciences is very much based on renal function being continuous - this is after all what we teach our students (future providers). Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharm

RE: [NMusers] Questions about identifiability

nds on what you are developing the model for... I'll leave the other questions for the time being. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 5044 F: +64 3 4

[NMusers] Academic position available

Stephen Duffull ([EMAIL PROTECTED]) or Professor Ian Tucker ([EMAIL PROTECTED]) Reference Number: A07/82 Closing Date: 20 July 2007. http://pharmacy.otago.ac.nz/pages/vacancies.html Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913

[NMusers] academic position available

Stephen Duffull ([EMAIL PROTECTED]) or Professor Ian Tucker ([EMAIL PROTECTED]) Reference Number: A07/82 Closing Date: 20 July 2007. http://pharmacy.otago.ac.nz/pages/vacancies.html Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin

RE: [NMusers] Minimization terminated ?

s with respect to convergence? I believe that the SAEM algorithm is proven to converge if run long enough - but of course how long is long enough is for the experts. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New

RE: [NMusers] Assigning occasions to sparse data

rval (e.g. 1 dose interval). [i.e. To be (perhaps inappropriately) provocative, if large estimated BOV is bad for your drug then all you need to do is make the occasion duration to be very long :-)] Just some thoughts. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy Un

[NMusers] Population Optimal Design ListServer (PopDesign)

Queensland, Australia Aris Dokoumetzidis, The University of Manchester, UK Stephen Duffull, University of Otago, NZ Steven Gilmour, Queen Mary, University of London, UK Gordon Graham, Pharmacometrics, Pfizer, UK Heiko Grossmann, Queen Mary, University of London, UK Iva Gueorguieva, Global

[NMusers] PAGANZ Meeting in Dunedin (NZ) 13-15 Feb 2008

: Bruce Charles, University of Queensland, Australia Stephen Duffull, University of Otago, New Zealand Bruce Green, University of Queensland, Australia Nick Holford, University of Auckland, New Zealand Carl Kirkpatrick, University of Queensland, Australia Diane Mould

[NMusers] Reminder: PAGANZ Meeting in Dunedin (NZ) 13-15 Feb 2008

abstracts: 11th January 2008 Note: registration, payment and abstract submission can all be done on-line at the PAGANZ web-site. *** Numbers are capped at 50 participants! *** Presenters include: == * Chuanpu Hu * Andrew Hooker * Nick Denman * Stephen Duffull * Nick Holford * Pavan

RE: [NMusers] Reporting Modeling Results

ut question that industry, regulatory and academia all play equally important roles in improving patient care. Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 50

RE: [NMusers] Reporting Modeling Results

calculate CLCR (based on LBM). Otherwise limited impact on already busy clinical pharmacy services. There are other examples (but I'm marking exams right now) but I'm sure others can comment here too. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmac

RE: [NMusers] Reporting Modeling Results

ote Einstein) - "the dosing regimen should be as simple as possible but not simpler..." Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com

RE: [NMusers] Reporting Modeling Results

se in academic settings that improve patient care [to respond to Mark's comments] and b) that simplifying the dosing on the drug label to make the drug "easier to use" doesn't necessarily result in better patient outcomes. Regards Steve -- Professor Stephen Duffull Ch

[NMusers] PAGANZ - register now

aces available in the Introduction to NONMEM workshop Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com

[NMusers] PAGANZ meeting

at: http://www.paganz.org/default.asp?id=42&keuze=meeting Kind regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com

RE: [NMusers] Body weight distribution

wever, e.g. general medical etc. It would depend on what population you wanted. However if you're interested in a multivariate distribution (e.g. the joint distribution of weight and height) then your choices are more limited. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy Sch

Re: [NMusers] Visual predictive check!

d concentration. And observed concentration perhaps should be termed "assay predicted concentration" while predicted concentration should be "PK model predicted concentration", but this is a bit of a mouthful. Regards Steve -- Professor Stephen Duffull School of Pharmacy Unive

RE: [NMusers] Sparse (pediatric) and rich (adult) data

rds Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com > -Original Message- > From: [EMAIL PROTECTED] > [mail

RE: [NMusers] Sparse (pediatric) and rich (adult) data

g a model that allows me to draw appropriately accurate conclusions. Optimal design is a way that allows investigators to improve the informativeness of data. Obviously, no data = no information. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago

RE: [NMusers] Sparse (pediatric) and rich (adult) data

Leonid > The original question was whether it is beneficial to add > adult data to the pediatric (in the specific case under > study). Your previous e-mail could be interpreted as the > suggestion that one can estimate model parameters with the > pediatric data alone if the pediatric study des

[NMusers] Lecturer/Senior Lecturer - Clinical Pharmacy/Pharmacokinetics

conducive to a high quality lifestyle. Specific enquiries may be directed to Professor Stephen Duffull, Chair in Clinical Pharmacy, School of Pharmacy, Tel 03 479 5044, Email [EMAIL PROTECTED] -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913

RE: [NMusers] Sparse (pediatric) and rich (adult) data

simultaneous analysis with sequential Bayesian analysis. I can't recall where it was published - but it's worth a read. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [EMAIL PROTECTED] P: +64 3 479 504

RE: [NMusers] Your suggestions/thoughts needed on allometric base or final model

Atul > It is always a good idea to estimate the allometric > coefficient if you have adequate (weight ranges, PK sampling > etc) data collected. An interesting point. If you estimate the allometric coefficient then it will almost always give a better fit to your data as your model has more d

RE: [NMusers] Your suggestions/thoughts needed on allometric base or final model

s statistically better ... At what stage you consider a covariate to be "fundamental" meaning it should never be excluded will depend on the circumstance. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: [

[NMusers] RE: VPC, NPC or PPC?

aditional VPCs don't work well (note we did this in WinBUGS). Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: stephen.duff...@otago.ac.nz P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com

RE: [NMusers] OMEGA BLOCK with mixture model?

dvantages of application of DIAG(3) as an alternative to BLOCK(2). Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: stephen.duff...@otago.ac.nz P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com

RE: [NMusers] OMEGA BLOCK with mixture model?

.karls...@farmbio.uu.se] > Sent: Thursday, 16 April 2009 11:07 p.m. > To: Stephen Duffull; drmo...@pri-home.net; > nele.pl...@nycomed.com; nmusers@globomaxnm.com > Subject: RE: [NMusers] OMEGA BLOCK with mixture model? > > Hi Steve, > > For a one-compartment model I think these are diffe

RE: [NMusers] estimating Ka from dataset combining rich sample study and sparse sampling study

e the differences between the two data sets would be to analyse them sequentially, perhaps with consideration for using the analysis from the Rich data as an informative prior for the analysis of the Sparse data and see where this leads you. Kind regards Steve -- Professor Stephen Duffull Cha

RE: [NMusers] Modeling of two time-to-event outcomes

Nick Your approach is an important first step. However, there remains the possibility of co-dependence in the marginal distribution of the data once you have included a common fixed effect in your models. I'm not sure that this can be specifically implemented in NONMEM for odd-type data. If

RE: [NMusers] Modeling of two time-to-event outcomes

gt; Sent: Wednesday, 22 July 2009 5:31 p.m. > To: Stephen Duffull > Cc: Nick Holford; nmusers > Subject: Re: [NMusers] Modeling of two time-to-event outcomes > > For 2 event-time responses, without regression, copula models are the > common way of handling bivariate event time mod

RE: [NMusers] Modeling of two time-to-event outcomes

ent? Yes. I would expect that the degree of co-dependence would decrease. > It would be helpful to me and perhaps to others if you could give some > specific example of what copulas contribute. I haven't seen a PKPD estimation application (yet). Steve -- Professor Stephen Duffull Chai

RE: [NMusers] Modeling of two time-to-event outcomes

t hope to account for co-dependence structure based on fixed effects only. Steve -- > > Stephen Duffull wrote: > > Hi Nick > > > > > >> I've been hearing about copulas for a couple of years now but > haven't > >> seen anything which r

RE: [NMusers] Modeling of two time-to-event outcomes

Nick > I still don't understand what this has to do with 'interval data'. Read "continuous data". Steve --

RE: [NMusers] Linear VS LTBS

Mats Just a comment on your comments below: "All models are wrong and I see no reason why the exponential error model would be different although I think it is better than the proportional error for most situations. " "Why would you not be able to get sensible information from models that don

RE: [NMusers] Linear VS LTBS

Mats > I think you're missing an important point. As I wrote to Nick, you will > never get concentrations reported regardless of their value. At some > point, > you will only get the information that concentration is below a limit > (LOQ,LOD,LO?). This you should take into account in your design.

RE: [NMusers] Honest measurements

Mats I agree with Nick. Negative "observed" concns do occur for assays, even in my limited time working with HPLC I have seen them, however due to LOD/LOQ they are never really looked for and certainly never reported... Steve > -Original Message- > From: owner-nmus...@globomaxnm.com [

[NMusers] THE SHEINER/ROWLAND ADVANCED COURSE IN PHARMACOKINETICS/PHARMACODYNAMICS

d and converse in English is essential. A limited number of places, at a reduced fee, are available to academic persons. Further details are available upon request to irene.s...@pkworkshops.com<mailto:irene.s...@pkworkshops.com>. -- Professor Stephen Duffull Chair of Clinical Pharmacy Schoo

[NMusers] RE: post-ACoP: How to train future pharmacometricians

knowledge, and factoring in some growth and applying an equilibrium model, we can predict the required training rate... Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: stephen.duff...@otago.ac.nz P: +6

[NMusers] RE: post-ACoP: How to train future pharmacometricians

pline is the total number of young faculty in pharmacometrics across the world. They say (at least Stephen Pinker does) that a language is officially dead when less than 6000 children speak it... Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy Universit

RE: [NMusers] advan8 vs. advan13 (CORRECTION)

Juergen (Bob, Nick, Leonid) FYI: In WinBUGS I also don't get problems with: > MU_1=THETA(1) > EXPP=MU_1+ETA(1) > EXPW=EXP(-EXPP) > BIO=1/(1.0+EXPW) Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dune

RE: [NMusers] installation problem for NONMEM7 G95 on server

t it will deactivate this endearing Win7 feature. Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 Dunedin New Zealand E: stephen.duff...@otago.ac.nz<mailto:stephen.duff...@otago.ac.nz> P: +64 3 479 5044 F: +64 3 479 70

RE: [NMusers] pfim

related to the various software (incl. pfim). Kind regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 Dunedin New Zealand E: stephen.duff...@otago.ac.nz P: +64 3 479 5044 F: +64 3 479 7034 W: http://pharmacy.otago.ac.nz/profiles

RE: [NMusers] Very big NONMEM

n to do simulation ... You can easily call NONMEM (for estimation) from S, R and MATLAB. Hence simulating the complex data sets and then calling NONMEM for the estimation process (once the data sets have been reduced to an appropriate size) is relatively simple. Regards Steve -- Professor Steph

RE: [NMusers] which fortran compiler works under windows 7

to install NM (at least I can't do it). There was a thread about this recently which gave details on how to disable this feature of Win7. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 Dunedin New Zealand E: stephen.duff

RE: [NMusers] Rational of using IOV

e. to reduce bias in estimates of the population mean parameter values). Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 Dunedin New Zealand E: stephen.duff...@otago.ac.nz<mailto:stephen.duff...@otago.ac.nz> P: +64 3 479 5044 F: +64

RE: [NMusers] Rational of using IOV

mbio.uu.se]<mailto:[mailto:mats.karls...@farmbio.uu.se]> Sent: Tuesday, 2 November 2010 3:11 p.m. To: Stephen Duffull; 'Nick Holford'; nmusers@globomaxnm.com<mailto:nmusers@globomaxnm.com> Subject: RE: [NMusers] Rational of using IOV Hi Steve, I think we can apply some mechanisti

RE: [NMusers] [Fwd: occasions during pregnancy]

nce routes. Once you have something that you think describes the biology then I think it would be important and interesting to explore inclusion of hierarchical random effects. Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 D

[NMusers] RE: Limited Sampling with Enterohepatic Recirculation

this nature (you need to join up at http://lists.otago.ac.nz/listinfo/popdesign to use it). I am not aware of any limited sampling software. Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 Dunedin New Zealand E: s

RE: [NMusers] question about shinkage

Hi Li I’m not aware of specific interpretations for negative shrinkage other than the evaluation of the SD of the ETAs is greater than the estimate of the sqrt of OMEGA for the same parameter. Since OMEGA itself is an estimate then ETA shrinkage may occur due to either the EBEs being underdisp

RE: [NMusers] Confidence intervals of PsN bootstrap output

rbitrary cut-off. But the devil here lies with the non-regulatory work where you may not have defined these boundaries a priori. Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 Dunedin New Zealand E: stephen.duff...@otago.ac.nz P: +64

RE: [NMusers] Confidence intervals of PsN bootstrap output

the results you're stuck. Would not a pragmatic view be appropriate? Report the outcomes of the BS runs as they occurred but then select those runs that terminated appropriately? Otherwise BS is too risky... Steve PS All models are wrong :-) -- > > > On 7/10/2011 2:57 P

RE: [NMusers] PRIORS

Hi Charles The choice of the df of the Wishart should be based on what your prior information provides not on what the posterior distribution tells you. I suspect, if your data is relatively uninformative then a sensitivity analysis will show that the posterior is sensitive to the prior. It w

RE: [NMusers] PRIORS

le 8256 Union Centre Blvd, IP-351 West Chester, OH 45069 johnson.r...@pg.com<mailto:johnson.r...@pg.com> (513) 634-9827 From: owner-nmus...@globomaxnm.com<mailto:owner-nmus...@globomaxnm.com> [mailto:owner-nmus...@globomaxnm.com] On Behalf Of Stephen Duffull Sent: Monday, January 30, 20

RE: [NMusers] OMEGA priors using modes of inverse Wishart matrix

Hi An appropriate value for dof of the IW is difficult to determine. While it can be set at n-1 from a prior this is somewhat arbitrary. It is not in this sense like a t-distn where we calculate dof in this manner. You would have to get a feeling for the degree of spread in your deviates give

[NMusers] RE: Dual inhibitor synergy model

the system. Regards Steve -- Professor Stephen Duffull<http://pharmacy.otago.ac.nz/our-people/academic-staff/stephen-duffull> Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 56 Dunedin New Zealand E: stephen.duff...@otago.ac.nz<mailto:stephen.duff...@otago.ac.nz&

RE: [NMusers] omega matrix - friendly suggestion

It turns out that there are many symmetric matrices where off-diagonals are between -1 and 1 that have negative determinants. Just to add my 2c there are also non-positive definite symmetric matrices that have positive determinants. Some are obvious and some are not. So if you were to paramete

[NMusers] 2 Day Introductory Workshop on NONMEM, Canberra, Australia, 6th & 7th December 2012 [Correct dates]

l of Pharmacy and Pharmaceutical Sciences, University of Manchester, UK. His research interests are in population and physiologically based pharmacokinetics. Stephen Duffull is Professor of Clinical Pharmacy at the University of Otago, Dunedin, New Zealand. He runs a modelling and simulation lab within

[NMusers] 2 Day Introductory Workshop on Pharmacokinetics and Pharmacodynamics,Canberra, Australia, 4th & 5th December 2012 [correct dates]

ysis. Faculty Leon Aarons is a Professor in the School of Pharmacy and Pharmaceutical Sciences, University of Manchester, UK. His research interests are in population and physiologically based pharmacokinetics. Stephen Duffull is Professor of Clinical Pharmacy at the University of Otago, Dunedin, New Zea

[NMusers] 2 Day Inroductory Workshop on Pharmacokinetics and Pharmacodynamics,Canberra, Australia, 9th & 10th February 2012

ysis. Faculty Leon Aarons is a Professor in the School of Pharmacy and Pharmaceutical Sciences, University of Manchester, UK. His research interests are in population and physiologically based pharmacokinetics. Stephen Duffull is Professor of Clinical Pharmacy at the University of Otago, Dunedin,

[NMusers] 2 Day Introductory Workshop on NONMEM, Canberra, Australia, 9th & 10th February 2012

l of Pharmacy and Pharmaceutical Sciences, University of Manchester, UK. His research interests are in population and physiologically based pharmacokinetics. Stephen Duffull is Professor of Clinical Pharmacy at the University of Otago, Dunedin, New Zealand. He runs a modelling and simulation lab wi

RE: [NMusers] Sample size calculation using PopDes

Hi Bernard There is an email listserver set up specifically for optimal design questions. See: http://lists.otago.ac.nz/listinfo/popdesign The software developers for PopDes are also members of this list. Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of

[NMusers] 16th Annual Scientific Meeting PAGANZ 2014 Jan 29-31 Dunedin New Zealand -- Registrations will open soon

d to seeing you next January! Regards, Steve Duffull On Behalf of the PAGANZ Organising Committee -- Professor Stephen Duffull, School of Pharmacy, University of Otago, PO Box 56, Dunedin 9054, New Zealand. Email: stephen.duff...@otago.ac.nz

[NMusers] Postdoctoral position

...@otago.ac.nz) Best regards Steve …....……… Stephen Duffull I Professor of Clinical Pharmacy | Dean Otago Pharmacometrics Group New Zealand’s National School of Pharmacy | Te Kura Mātauraka Wai-whakaora University of Otago | Te Whare

RE: [NMusers] Calculation of half life

Santosh Perhaps a more pertinent question is – Why do you want to know half-life? Steve …....……… Stephen Duffull I Professor of Clinical Pharmacy | Dean Otago Pharmacometrics Group New Zealand’s National School of Pharmacy | Te Kura

RE: [NMusers] Using evid 0 before dosing

, since this is generally not the case (i.e. the assay result is not reported exactly) then I agree it will not provide useful information to the estimation process. Cheers Steve …....……… Stephen Duffull<http://www.otago.ac

RE: [NMusers] OFV by endpoint of joint models?

Stephen Duffull | Professor Otago Pharmacometrics Group School of Pharmacy | He Rau Kawakawa University of Otago | Te Whare Wānanga o Otāgo Dunedin | Ōtepoti Aotearoa New Zealand Ph: 64 3 479 5099 -Original Message- From: owner-nmus...@globomaxnm.com On Behalf Of Jeroen Elassaiss

RE: [NMusers] OFV by endpoint of joint models?

multiple response model and thought that a quick way of doing this was to grab the relative contribution from CIWRES. Cheers Steve From: Jeroen Elassaiss-Schaap (PD-value) Sent: Tuesday, 11 October 2022 8:36 am To: Stephen Duffull Cc: Matts Kågedal ; nmusers@globomaxnm.com Subject: Re: [NMusers

[NMusers] Certara workshops at PAGE 2023: Effective Visualisations for Pharmacometrics models & CAR-T Population Kinetic Analysis

Certara is pleased to be offering two workshops prior to the PAGE 2023 meeting in A Coruña, Spain. Effective Visualizations for Pharmacometrics Models (VACHETTE) Effectively visualizing pharmacometrics models and data is crucial to inform high-quality drug discovery and development decision

RE: [External email][NMusers] Sad news about Dr. Ludden

I agree. While I only met Tom in person a few times we interacted quite a bit in my early days of PMx and NONMEM. Tom was immensely clever, kind, unassuming, understanding and supportive. A pleasure to chat with and to learn from. Steve Stephen Duffull Senior Scientific Advisor, Certara