AB.withDescalation {TrialSize}

A + B Escalation Design with Dose De-escalation

Description

The general A+B designs with dose de-escalation. There are A patients at dose level i.

(1) If less than C/A patients have dose limiting toxicity (DLTs), then the dose is escalated to the next dose level i+1.

(2)If more than D/A (D \ge C) patients have DLTs, then it will come back to dose i-1.If more than A patients have already been treated at dose level i-1, it will stop here and dose i-1 is the MTD. If there are only A patients treated at dose i-1, then Bmore patients are treated at this dose level i-1. This is dose de-escalation. The de-escalation may continue to the next dose level i-2 and so on if necessary.

(3)If no less than C/A but no more than D/A patients have DLTs, B more patients are treated at this dose level i.

(4)If no more than E (where E \ge D) of the total A+B patients have DLT, then the dose is escalated.

(5)If more than E of the total of A+B patients have DLT, and the similar procedure in (2) will be applied.

Usage

AB.withDescalation(A, B, C, D, E, DLT)

Arguments

A

number of patients for the start A

B

number of patients for the continuous B

C

number of patients for the first cut off C

D

number of patients for the second cut off D, D \ge C

E

number of patients for the third cut off D, E \ge D

DLT

dose limiting toxicity rate for each dose level.

Note

For this design, the MTD is the dose level at which no more than E/(A+B) patients experience DLTs, and more than D/A or (no less than C/A and no more than D/A) if more than E/(A+B) patients treated with the next higher dose have DLTs.

References

Chow SC, Shao J, Wang H. Sample Size Calculation in Clinical Research. New York: Marcel Dekker, 2003

Examples

DLT=c(0.01,0.014,0.025,0.056,0.177,0.594,0.963)
Example.11.6.2<-AB.withDescalation(A=3,B=3,C=1,D=1,E=1,DLT=DLT)
Example.11.6.2
# Example.11.6.2[7]=0.2