3 + 3 designs are very popular in phase I clinical trials. Given the assumed probabiliy of toxicity reactions at each dose level, this program computes the probability of each dose being the maximum tolerable dose (MTD), and the expected numbers of total patients and toxicity reactions. In addition, it gives the distributions of sample size and number of toxicity reactions.

This is not a simulation; the numbers are based on exhaustive computation of all possible sample paths according to binomial probabilities.

Up to 6 dose levels and 5 scenarios (assumed probabilities at each dose level) may be specified.

  dose 1dose 2dose 3dose 4 dose 5dose 6
scenario 1
scenario 2
scenario 3
scenario 4
scenario 5
  Starting dose level  


• This program is written in R (r-project.org).
    The "brew" package is used to integrate R and HTML.