Table 7.

Difference in Toxicity Needed To Get Below 10% or 20% Power With U_t = 0.3 and 10% Toxicity in One Arm^a

N Per Group	10% Power		20% Power
	HR = 0.50	HR = 0.75	HR = 0.50	HR = 0.75
50	56	16	47	4
100	60	23	54	13
150	61	25	56	18
200	62	26	58	20
300	63	28	60	23
500	64	28	61	26
1000	65	31	64	29

HR = hazard rate.

For n = 100 per group, if one arm has 10% of days with toxicity and the other arm has a lower hazard rate of 0.50 but 60% more days with toxicity (a total of 70% of days with toxicity), then there is only a 10% chance that the results will be significantly different. Therefore, the study will likely report no difference in QALYs although the overall survival rate is lower in one arm.

^aLikely to report no significant difference between groups even with one arm having a lower hazard rate because it also has more toxicity.