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Table 3 Statistical power assuming various event rates and treatment effects

From: Design and rationale for the prospective treatment efficacy in IPF using genotype for NAC selection (PRECISIONS) clinical trial

Placebo event rate (%)

NAC event rate* (%)

Event rate reduction (%)

Power** (%)

24

6.0

75

97.5

30

7.5

75

99.3

36

9.0

75

99.8

24

8.0

66.7

90.1

30

10.0

66.7

96.0

36

12.0

66.7

98.7

24

12.0

50

62.3

30

15.0

50

73.1

36

18.0

50

80.6

  1. *12-month event rates for the 35% of patients not taking concomitant IPF medication. The remaining 65% are assumed to have half the shown event rate in each arm based on taking IPF concomitant medication
  2. **Power estimates assume censorship/dropout rate of 10% for the NAC vs placebo comparison in 200 randomized participants. Calculations assume a 2-sided Type-I error rate of 0.05. Follow-up is planned to be 24 months for all patients. Power calculations were based on a log-rank test with assumed event rates following an exponential distribution