Table 1.

Illustrating how the "Intention to treat" approach ascribing indeterminate treatment outcomes as failures overestimates the true failure rate. High failure rate:

Follow-up	A (%)	R = F(%)	FITT (%)	Overestimation of failure rate (%)
6 weeks	6	15	15.3	2%
8 weeks	20	25	26	4%
10 weeks	45	25	27.25	9%
12 weeks	68	25	28.4	14%
20 weeks	75	25	28.75	15%

Assume that the entomological inoculation rate is 1/month (Figure 4), the true failure rate (F) is 25%, and 5% of PCR pairs are indeterminate. The patients are censored when a recurrent infection occurs.

Then at 4 weeks follow-up in the trial, the recurrence rate = 3.5% (2.5% true recrudescence, 1% true recurrence)

True failure rate = 2.5%, ITT analysis failure rate = 2.55%, overestimation 1.275%. F_ITT (%) = A + 0.05 R

A – cumulative probability of developing a patent new infection

R – cumulative probability of developing a patent recrudescence