Intravenous tocilizumab for the treatment of giant cell arteritis: a phase Ib dose-ranging pharmacokinetic bridging study

Table 3 Steady-state PK parameters of TCZ IV 7 and 6 mg/kg Q4W

PK parameters, mean, median (range)	7 mg/kg IV (period 1), n = 22^a	6 mg/kg IV (period 2), n = 22
C_max, μg/mL	205	182
C_max, μg/mL	197 (118–352)	178 (115–320)
AUC_τ, day•μg/mL	2150	1720
AUC_τ, day•μg/mL	2130 (1120–4300)	1610 (921–3070)
C_mean, μg/mL	76.9	61.5
C_mean, μg/mL	76.0 (40.1–154)	57.5 (32.9–110)
C_trough, μg/mL	35.3	22.7
C_trough, μg/mL	37.2 (6.59–69.0)	22.7 (3.38–54.5)
T_max, days	0.38	0.05
T_max, days	0.05 (0.04–6.97)	0.05 (0.04–0.06)
T_1/2, days^b	19.0	12.1
T_1/2, days^b	14.8 (5.86–120.0)	13.2 (4.69–21.9)

AUC_τ Area under the curve over a dosing interval (τ), C_max Maximum concentration, C_mean Mean concentration (AUC_τ/τ), C_trough Minimum (trough) concentration, IV Intravenous, PK Pharmacokinetics, Q4W Every 4 weeks, T_1/2 Half-life, TCZ Tocilizumab, T_max Time to C_max
^an = 21 for C_max
^bT_1/2 of TCZ is concentration-dependent; extrapolation from noncompartmental analysis should be made with caution

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