Let rho0 = p(xmin) be the probability of a DLT at the minimum dose
xmin, and let gamma be the dose with target toxicity probability theta,
i.e. \(p(gamma) = theta\). Then it can easily be shown that the logistic
regression model has intercept
$$[gamma * logit(rho0) - xmin * logit(theta)] / [gamma - xmin]$$
and slope
$$[logit(theta) - logit(rho0)] / [gamma - xmin].$$
The priors are $$gamma ~ Unif(xmin, xmax).$$ and
$$rho0 ~ Unif(0, theta).$$