Visilizumab pharmacokinetics and T-cell recovery.

(A) Mean ± SEM serum concentrations of visilizumab in patients treated with 7 doses of 0.25 mg/m² (□, n = 3) or 1.0 mg/m² (●, n = 3). Mean ± SEM serum concentrations of visilizumab in patients given a single dose of 3 mg/m²(■). Results are from days 0, 1 (n = 11), 2, 7, 14, 21 (n = 10), 28, 35 (n = 9), and 42 (n = 8). (B) Before therapy, absolute T-cell counts were 21 to 877/μL (median, 65/μL). After therapy, absolute T-cell counts increased as visilizumab serum levels decreased. Absolute T-cell counts were 80 to 1014/μL (median, 433/μL) at a median of 72 days (range, 42-81 days) following antibody clearance in 8 evaluable patients.