TRAFIC: statistical design and analysis plan for a pragmatic early phase 1/2 Bayesian adaptive dose escalation trial in rheumatoid arthritis

Table 1 Prior probability that each Dose Level is the MTD for differing σ_β, δ=0.06

Dose level	Prior SD of slope parameter β, σ_β
Dose level	0.1	σ_β^LI *= 0.265*	√1.34 =1.16
1 (200 mg)	0.01	0.20	0.42
2 (400 mg)	0.22	0.19	0.05
3 (600 mg)	0.54	0.22	0.05
4 (800 mg)	0.22	0.19	0.05
5 (1000 mg)	0.01	0.20	0.42

Note: a large σ_β does not necessarily correspond to an uninformative prior for MTD level; √1.34 is often chosen as the default value for CRM models. The least informative value of σ_β is one where there are almost equal prior probabilities (chance) that each dose level is the MTD across the 5 dose levels

ISSN: 1745-6215