Table 3.

Stopping Eculizumab Treatment Safely in aHUS trial stopping boundaries

Number of patients (in complete cohorts of 5)	Stop the trial for superiority if there are these many TMA events (inclusive)	Continue the trial if there are these many TMA events (inclusive)	Stop the trial for inferiority if there are these many TMA events (inclusive)
5	Never stop for superiority with these many patients	0–1	2–5
10 or 15	Never stop for superiority with these many patients	0–2	3–15
20	Never stop for superiority with these many patients	0–3	4–20
25 or 30	Never stop for superiority with these many patients	0–4 (the trial always stops at 30 patients, which is the maximum)	5–30