Create target object — create_target

This function helps the user define the PKPD target for a simulation. When a minimum value and maximum value are supplied, the algorithm targets the mid- point. Alternatively, a single midpoint can be supplied.

Usage

create_target_design(
  targettype = mipd_target_types(),
  targetmin = NULL,
  targetmax = NULL,
  targetvalue = NULL,
  single_point_variation = 0.2,
  time = NULL,
  when = NULL,
  offset = NULL,
  at = NULL,
  anchor = c("dose", "day")
)

Arguments

targettype: target type, one of accepted types (see mipd_target_types())
targetmin: minimum value acceptable, must be specified with targetmax. Can be a vector. In that case, length has to match length of other vector-arguments to this function, and length of regimen update occasions.
targetmax: maximum value acceptable, must be specified with targetmin. Can be a vector. In that case, length has to match length of other vector-arguments to this function, and length of regimen update occasions.
targetvalue: value for a target, overrides min and max values. Can be a vector. In that case, length has to match length of other vector-arguments to this function, and length of regimen update occasions.
single_point_variation: acceptable variation from targetvalue. By default 20%. Considered for assessment of target attainment a posteriori, not used for dose-finding logic.
time: a vector of numeric values at which to measure and optimize the target. In most cases time is not required as argument, and will be inferred from the the targettype. If at values are supplied, the target times will be calculated adaptively during the trial. The at determine which dose is used as reference anchor. and time will be relative to the specified at. If no at values are specified, the time values will be used as the fixed absolute target times in the simulated trial.
when: character vector of same length as time (or single value) determining how to interpret the provided target time. If NULL will use the dose time as offset (default). Other options are cmax or peak, which will use the end of infusion as the base for the time, or cmin or trough, which will use the time of next dose as the offset.
offset: offset from a when moment (dose, peak, or trough).
at: numeric vector of the dose or day number to "anchor" the target times to. Vector needs to be of same length as t. If anchor is set to day, then the first dose in that day is used. If later doses in the day are preferred, the anchor can also be specified fractionally, e.g. 1.5 will use the time of the first dose in the second half of the 1st day.
anchor: either day or dose. Single value required, i.e. anchor types cannot be mixed.

Examples


## Target cumulative AUC, always exactly at 72 hours:
create_target_design(
  targettype = "cum_auc",
  targetvalue = 90,
  time = 72
)
#> $type
#> [1] "cum_auc"
#> 
#> $value
#> [1] 90
#> 
#> $min
#> [1] 72
#> 
#> $max
#> [1] 108
#> 
#> $scheme
#>   base offset at anchor
#> 1 dose     72  1   dose
#> 

## Target trough concentration at trough after dose 4.
create_target_design(
  targettype = "cmin",
  targetvalue = 15,
  at = 4,
  anchor = "dose"
)
#> $type
#> [1] "cmin"
#> 
#> $value
#> [1] 15
#> 
#> $min
#> [1] 12
#> 
#> $max
#> [1] 18
#> 
#> $scheme
#>   base offset at anchor scatter
#> 1 cmin      0  4   dose       0
#> 

## Target AUC24 over day 4
create_target_design(
  targettype = "auc24",
  targetvalue = 500,
  at = 4,
  anchor = "day"
)
#> $type
#> [1] "auc24"
#> 
#> $value
#> [1] 500
#> 
#> $min
#> [1] 400
#> 
#> $max
#> [1] 600
#> 
#> $scheme
#>   base offset at anchor scatter
#> 1 dose     24  4    day       0
#> 

## Target cmin first at dose 4 (15 mg/L), then at dose 8 (25 mg/L)
create_target_design(
  targettype = "cmin",
  targetvalue = c(15, 25),
  at = c(4, 8),
  anchor = "day"
)
#> $type
#> [1] "cmin"
#> 
#> $value
#> [1] 15 25
#> 
#> $min
#> [1] 12 20
#> 
#> $max
#> [1] 18 30
#> 
#> $scheme
#>   base offset at anchor scatter
#> 1 cmin      0  4    day       0
#> 2 cmin      0  8    day       0
#>