Safety and tolerability of an anti-CD19 monoclonal antibody, MEDI-551, in subjects with systemic sclerosis: a phase I, randomized, placebo-controlled, escalating single-dose study

Table 4 Summary of B cell depletion activity of MEDI-551

MEDI-551 Dose	Subjects, n	Subjects achieving depletion,^a n (%)	Time to depletion,^b,c median (range), days	Duration of depletion,^b,d median (range), days	Maximum B cell reduction,^e mean % (SD)
0.3 mg/kg	4	2 (50.0)	43.5 (30–57)	13.5 (0–27)	89.7 (3.9)
1.0 mg/kg	6	5 (83.3)	57.0 (29–67)	29.0 (0–209)	93.0 (10.2)
3.0 mg/kg	6	5 (83.3)	29.0 (7–85)	119 (0–154)	93.4 (10.9)
10.0 mg/kg	7	7 (100.0)	28.0 (3–86)	231 (30–264)	98.3 (3.2)

^aDefined as ≥ 90 % reduction in B cell counts from the day 1 value
^bAmong subjects who achieved B cell depletion
^cDefined as the time to the first observation of ≥90 % reduction from the day 1 value
^dDefined as the interval between the first and last observation of ≥90 % reduction in B cell count from the day 1 value. Subjects with B cell depletion at only a single assessment had a duration of depletion of zero
^eValues represent mean of the maximum degree of B cell reduction for subjects in the group, at any time after dosing, expressed as % reduction of day 1 values

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