. 2021 Feb 2;14(3):1069–1081. doi: 10.1111/cts.12972

Table 2.

Probability of consistency (East Asian vs. overall trial population)

Parameter	EFS Scenario A	EFS Scenario B	OS	OS
Analysis timepoint	Month 35–50 (IA3) ^a	Month 35–50 (IA3) ^a	Month 35–50 (IA3) ^a	Month 63 (FA)
Treatment effect (median) ^b	Pevonedistat‐azacitidine arm: 22.2 months Azacitidine arm: 13 months	Pevonedistat‐azacitidine arm: 19.6 months Azacitidine arm: 13 months	Pevonedistat‐azacitidine arm: 36.95 months Azacitidine arm: 24.5 months	Pevonedistat‐azacitidine arm: 36.95 months Azacitidine arm: 24.5 months
Number of overall patients randomized	~450	~450	~450	~450
Number of East Asian patients randomized	30	30	30	30
Expected number of events in East Asian patients	17–21	18–22	13–17	19
Consistency probability	85.9–88.0%	80.7–82.8%	76.5–79.3%	81.3%

Abbreviations: EFS, event‐free survival; FA, final analysis; IA2, second interim analysis; IA3, third interim analysis; OS, overall survival.

^{^a}

The minimum and maximum EFS event size required for the IA3 in the overall population were specified as 147 and 249, respectively, in the study. The exact number of EFS events at IA3 depends on the IA2 results, where an event‐size re‐estimation is performed. It was projected at the start of the study that it would take 35 and 50 months to collect 147 and 249 EFS events, respectively. Expected number of events in East Asian patients and consistency probabilities were calculated and presented in intervals assuming IA3 is conducted sometime between 35 and 50 months after first patient is randomized.

^{^b}

There are two treatment effect scenarios (A and B) for EFS that were used to determine minimum and maximum planned event size. EFS and OS are assumed to be exponentially distributed.