*! version 1.0 14 Jul 2020

Title

mtpi -- A command for the modified Toxicity Probability Interval design

Syntax

mtpi
[varlist]
[,
options]

Optional
ep1(#) specifies the lower bound of the interval around the TTL that is safe.

ep2(#) specifies the upper bound of the interval around the TTL that is safe.

safe1(#) specifies the safety cutoff for declaring the lowest dose to be safe.

safe2(#) specifies the safety cutoff for declating the dose to be safe.

ttl(#) specifies the target toxicity level that defines the maximum tolerated dose.

simn(#) specifes the number of simulations used

sampsize(#) specifies the sample size of each trial in the simulations.

csize(#) specifies the cohort size used in the trial.

startdose(#) specifies the starting dose.

priora(#) specifies the a parameter of the prior Beta distribution.

priorb(#) specifies the a parameter of the prior Beta distribution.

truep(numlist ascending >=0 <=1) specifies a vector of true probabilities of DLT for each dose level.

decisiontable specifies that the single cohort decision rules be displayed as a lookup table.

Description

The modified Toxicity Probability Interval design is an attempt to implement a method
that is as simple as a 3+3 decision but based on statistical distributions rather
than a pure rule-based approach. This method produces decision making tables for the fully
trial so a statistician need not be involved in all the dose escalation decisions.

The command mtpi performs simulations to find the operating characteristics alongside
the decision matrix given a sample size and number of DLTs.

Options

Main

ep1(#) specifies the lower bound of the interval around the TTL that is safe.

ep2(#) specifies the upper bound of the interval around the TTL that is safe.

safe1(#) specifies the safety cutoff for declaring the lowest dose to be safe.

safe2(#) specifies the safety cutoff for declating the dose to be safe.

ttl(#) specifies the target toxicity level that defines the maximum tolerated dose.

simn(#) specifes the number of simulations used

sampsize(#) specifies the sample size of each trial in the simulations.

csize(#) specifies the cohort size used in the trial.

startdose(#) specifies the starting dose.

priora(#) specifies the a parameter of the prior Beta distribution.

priorb(#) specifies the a parameter of the prior Beta distribution.

truep(numlist ascending >=0 <=1) specifies a vector of true probabilities of DLT for each dose level.

decisiontable specifies that the single cohort decision rules be displayed as a lookup table.

Examples

The basic command will do a simulation

mtpi

The results show a table of each dose level with the true probabilities of a DLTs
and the proportion of time those doses are recommended, experimented
on and how many DLTs were observed on average.

References

Yuan Ji, Ping Liu, Yisheng Li and NB Bekele (2010) A modified toxicity probability
interval method for dose-finding trials. Clin. Trials 7(6) 653-663.

Author

Prof Adrian Mander, Cardiff University.

Email mandera@cardiff.ac.uk

See Also

Related commands:

crm (if installed) ssc install crm (to install this command)