Re: seeking help on NONMEM code for simulation of Repeated Time to Event Data

From: Leonid Gibiansky Date: April 03, 2013 technical Source: mail-archive.com
Yaming Could you, please, add some more details about the procedure to determine the time of the event/dose. Is it some numerical integral of hazard, and when it reaches some value (integral from 0 to T0) then the dose is given at T0 ? Or you can determine it earlier, say by time T1 < T0 (where T1 is known in advance)? Leonid -------------------------------------- Leonid Gibiansky, Ph.D. President, QuantPharm LLC web: www.quantpharm.com e-mail: LGibiansky at quantpharm.com tel: (301) 767 5566
Quoted reply history
On 4/3/2013 4:35 PM, Yaming Hang wrote: > Dear NONMEM Users, > > I have some questions about how to accomplish the following tasks in > NONMEM, would you kindly share your experience with me or provide some > suggestions? I’m trying to make a simulation that involves dynamic > dosing. Here is the algorithm of simulation: at time 0, a dose is given, > then the time to the first event will be simulated based on a certain > survival function which depends on the drug exposure. Next, conditioning > on that simulated first event time, a second dose will be introduced, > and again time to the second event will be simulated. This will be > repeated until a certain cut off time point. > > My specific questions are: > > 1. since the dosing history will be depending on the simulated event > time, I cannot construct the dosing history in NONMEM data set a prior, > how can this be done? > > 2. The survival function is a function of the time-varying drug > exposure, therefore I need to inverse an integral which does not have a > closed form (i.e. only expressed in differential equation), how can I do > that? > > Your help will be much appreciated! > > Yaming Hang