Variables of AdaptInfo

Gabriel Potvin

October 31, 2025

The variables in AdaptInfo define the sample size re-estimation design parameters. They can be used in custom scripts for the Analysis Integration Point and the Treatment Selection Integration Point. To access these parameters in your R code, use the syntax: AdaptInfo$NameOfTheVariable, replacing NameOfTheVariable with the appropriate parameter name.

The tables below describe each variable and notes any conditions under which it can or cannot be used in a project on East Horizon Explore and East Horizon Design. Availability notes are only specified when they differ from the default availability of the integration points (see the pages linked above for details).

AdaptInfo is only available for Statistical Design = Group Sequential with Sample Size Re-Estimation (for Design, Adaptation Method = Cui, Hung, and Wang (CHW) or Chen, DeMets, and Lan (CDL). Not available for Endpoint Type = Continuous with Repeated Measures or Dual Endpoint (TTE-TTE or TTE-Binary) or Study Objective = Multiple Arm COnfirmatory.

For Study Objective = Two Arm Confirmatory

For Endpoint Type = Continuous, Binary, Time-to-Event

Variable	Type	Description	Notes
AdaptMethod	Integer	Adaptation method: - 1: Cui, Hung, and Wang (CHW). - 2: Chen, DeMets, and Lan (CDL).
AdaptInterimScale	Integer	Adapt at interim analysis scale: - 1: Interim analysis number. - 2: Analysis spacing info (%).	Fixed to 1 for East Horizon Explore and for AdaptMethod = 2 (CDL).
AdaptInterimNum	Integer	Interim analysis number at which adaptation will happen.	Fixed to LookInfo$NumLooks - 1 for AdaptMethod = 2 (CDL).
AdaptInterimPerc	Integer	Analysis spacing info (%) at which adaptation will happen.	Available only for AdaptMethod = 2 (CDL).
StudyDurationUL	Numeric	Upper limit on study duration.	Not available for East Horizon Explore.
WaldCPThreshold	Numeric	Threshold beyond which Wald statistics are used.	Available only for AdaptMethod = 2 (CDL).
EnrollAdaptScale	Integer	Scale for enrollment rate after adaptation: - 0: No change. - 1: Use multiplier. - 2: Use fixed rate.	EnrollAdaptScale = 2 (fixed rate) is only applicable for East Horizon Design.
EnrollAdaptMult	Numeric	Multiplier for enrollment rate after adaptation.	Available only for EnrollAdaptScale = 1 (use multiplier).
EnrollAdaptRate	Numeric	Fixed enrollment rate after adaptation.	Available only for EnrollAdaptScale = 2 (use fixed rate).
PromZoneScale	Integer	Promising zone scale: - 0: Estimated conditional power. - 1: Arbitrary/design conditional power. - 2: Test statistic. - 3: Estimated delta/sigma.
PromZoneSigma	Numeric	Reference/design sigma for computing promising zone conditional power.	Available only when PromZoneScale = 1 (Arbitrary/design conditional power).
PromZoneDelta	Numeric	Reference/design delta for computing promising zone conditional power.	Available only when PromZoneScale = 1 (Arbitrary/design conditional power).
PromZoneMin	Numeric	Minimum threshold for promising zone.
PromZoneMax	Numeric	Maximum threshold for promising zone.
SSRFuncScale	Numeric	Sample size re-estimation function scale for promising zone: - 0: Continuous. - 1: Step. - 2: User-specified R.	SSRFuncScale = 1 (step) is available only in East Horizon Explore.
NumSteps	Integer	Number of steps.	Available only for SSRFuncScale = 1 (step).
MaxSSMultInp	Named List	Maximum sample size multiplier inputs.	If SSRFuncScale = 0 (continuous), it is a Named List of Numeric: - MaxSSMultInp[“From”] = PromZoneMin. - MaxSSMultInp[“To”] = PromZoneMax. - MaxSSMultInp[“MaxSSMult”] is a numeric specified by the user. If SSRFuncScale = 1 (step), it is a Named List of Array of Numeric: - MaxSSMultInp[“From”] is an array of size NumSteps containing the lower threshold for each step. - MaxSSMultInp[“To”] is an array of size NumSteps containing the upper threshold for each step. - MaxSSMultInp[“MaxSSMult”] is an array of size NumSteps containing the maximum sample size multiplier for each step.
TargetCP	Numeric	Target conditional power.	Available only for SSRFuncScale = 0 (continuous).
OrigCP	Numeric	Conditional power computed from the maximum number of completers/events.