RE: Phase III trail popPK sample size

From: "Stephen Duffull" stephen.duffull@stonebow.otago.ac.nz Subject: RE: [NMusers] Phase III trail popPK sample size Date: Fri, 17 Nov 2006 18:18:36 +1300 Mei >> impossible to collect samples from all patients ($$?). We >> want to randomly select a subpopulation to collect PK >> samples. I was wondering what is the "typical" number of PK >> samples and subjects reported in phase III PopPK study? It depends on 1) the structure and complexity of your PKPD model 2) study visit times 3) the maximum number of samples allowable per patient 4) and the goals you have for doing popPKPD modelling in phase III. >> We have already developed the Pop PK/PD model based on the >> Phase I and II study. According to FDA popPK guidance, the >> sample scheme can be multiple trough points or optimal sample >> points. I was wondering which one is better. Optimal samples are always better than non-optimal samples. You could frame the problem as "what is the minimum number of patients that you have to include in your PKPD study and how many clinic visits do I need to take samples for PKPD analysis?". This fits very nicely within the framework of optimal design - and you could consider using a program such as WinPOPT (www.winpopt.com) to help answer this question. Regards Steve -- Professor Stephen Duffull Chair of Clinical Pharmacy School of Pharmacy University of Otago PO Box 913 Dunedin New Zealand E: stephen.duffull@otago.ac.nz P: +64 3 479 5044 F: +64 3 479 7034 Design software: www.winpopt.com _______________________________________________________