Table 2. Variable regions used in the cynomolgus monkey PK study.

Variable region	KD at pH 7.4 (M)	KD at pH 5.8 (M)	kd at pH 5.8 (s-1)	Charge engineering
305LO1	5.97 × 10−9	3.31 × 10−5	4.00 × 10−2	not performed
305LO5	4.81 × 10−10	1.92 × 10−7	1.21 × 10−2	not performed
305LO8	1.01 × 10−9	5.12 × 10−7	3.58 × 10−2	performed

Each of three variable regions, 305LO1, 305LO5, 305LO8, was fused with a human IgG₁ constant region, and the binding kinetics against recombinant cynomolgus C5 were measured by Biacore. 305LO8 was engineered to have an optimal surface charge.