NextBestNCRM-class: 'NextBestNCRM'

In crmPack: Object-Oriented Implementation of Dose Escalation Designs

NextBestNCRM

Description

NextBestNCRM is the class for next best dose that finds the next dose with high posterior probability to be in the target toxicity interval.

Usage

NextBestNCRM(target, overdose, max_overdose_prob)

.DefaultNextBestNCRM()

Arguments

target	(numeric) see slot definition.
overdose	(numeric) see slot definition.
max_overdose_prob	(proportion) see slot definition.

Details

To avoid numerical problems, the dose selection algorithm has been implemented as follows: First admissible doses are found, which are those with probability to fall in overdose category being below max_overdose_prob. Next, within the admissible doses, the maximum probability to fall in the target category is calculated. If that is above 5% (i.e. it is not just numerical error), then the corresponding dose is the next recommended dose. Otherwise, the highest admissible dose is the next recommended dose.

Slots

target

(numeric)
the target toxicity interval (limits included).

overdose

(numeric)
the overdose toxicity interval (lower limit excluded, upper limit included). It is used to filter probability samples.

max_overdose_prob

(proportion)
maximum overdose posterior probability that is allowed, except 0 or 1.

Note

Typically, end users will not use the .DefaultNextBestNCRM() function.

Examples

# In the example below, the target toxicity interval [0.2, 0.35] while the
# overdose interval is (0.35,1]. Finally we would like to constrain the
# probability of overdosing below 25%.
my_next_best <- NextBestNCRM(
  target = c(0.2, 0.35),
  overdose = c(0.35, 1),
  max_overdose_prob = 0.25
)

crmPack documentation built on Nov. 29, 2025, 5:07 p.m.