;Intravenous Administration
The pharmacokinetics characterized in healthy subjects and RA patients suggested that PK is similar between the two populations. The clearance (CL) of tocilizumab decreased with increased doses. At the 10 mg per kg single dose in RA patients, mean CL was 0.29 ± 0.10 mL per hr per kg and mean apparent terminal t1/2 was 151 ± 59 hours (6.3 days).
The pharmacokinetics of tocilizumab were determined using a population pharmacokinetic analysis of 1793 rheumatoid arthritis patients treated with ACTEMRA 4 and 8 mg per kg every 4 weeks for 24 weeks.
The pharmacokinetic parameters of tocilizumab did not change with time. A more than dose-proportional increase in area under the curve (AUC) and trough concentration (Cmin) was observed for doses of 4 and 8 mg per kg every 4 weeks. Maximum concentration (Cmax) increased dose-proportionally. At steady-state, estimated AUC and Cmin were 2.7 and 6.5-fold higher at 8 mg per kg as compared to 4 mg per kg, respectively. In a long-term study with dosing for 104 weeks, observed Cmin was sustained over time.
For doses of ACTEMRA 4 mg per kg given every 4 weeks, the estimated mean (± SD) steady-state AUC, Cmin and Cmax of tocilizumab were 13000 ± 5800 mcg∙h per mL, 1.49 ± 2.13 mcg per mL, and 88.3 ± 41.4 mcg per mL, respectively. The accumulation ratios for AUC and Cmax were 1.11 and 1.02, respectively. The accumulation ratio was higher for Cmin (1.96). Steady-state was reached following the first administration for Cmax and AUC, respectively, and after 16 weeks Cmin. For doses of ACTEMRA 8 mg per kg given every 4 weeks, the estimated mean (± SD) steady-state AUC, Cmin and Cmax of tocilizumab were 35000 ± 15500 mcg∙h per mL, 9.74 ± 10.5 mcg per mL, and 183 ± 85.6 mcg per mL, respectively. The accumulation ratios for AUC and Cmax were 1.22 and 1.06, respectively. The accumulation ratio was higher for Cmin (2.35). Steady-state was reached following the first administration and after 8 and 20 weeks for Cmax, AUC, and Cmin, respectively. Tocilizumab AUC, Cmin and Cmax increased with increase of body weight. At body weight at or above 100 kg, the estimated mean (± SD) steady-state AUC, Cmin and Cmax of tocilizumab were 55500 ± 14100 mcg∙h per mL, 19.0 ± 12.0 mcg per mL, and 269 ± 57 mcg per mL, respectively, which are higher than mean exposure values for the patient population. Therefore, ACTEMRA doses exceeding 800 mg per infusion are not recommended [see DOSAGE AND ADMINISTRATION (2.1)].
Rheumatoid Arthritis—Subcutaneous Administration
The pharmacokinetics of tocilizumab was characterized using a population pharmacokinetic analysis using a database composed of 1759 rheumatoid arthritis patients treated with 162 mg SC every week, 162 mg SC every other week, and 8 mg/kg every 4 weeks for 24 weeks.
The pharmacokinetic parameters of tocilizumab did not change with time. For the 162 mg every week dose, the estimated mean (±SD) steady-state AUC1week, Cmin and Cmax of tocilizumab were 8200 ± 3600 mcg∙h/mL, 44.6 ± 20.6 mcg/mL, and 50.9 ± 21.8 mcg/mL, respectively. The accumulation ratios for AUC, Cmin, and Cmax were 6.83, 6.37, and 5.47, respectively. Steady state was reached after 12 weeks for AUC, Cmin, and Cmax.
For the 162 mg every other week dose, the estimated mean (±SD) steady-state AUC2week, Cmin, and Cmax of tocilizumab were 3200 ± 2700 mcg∙h/mL |
