Table 4.

Comparison of key attributes of 22-20, 20-22, 20-20, v-mab, rituximab (r-mab), and e-mab

Attribute	22-20	20-22	20-20	v-mab	r-mab	e-mab
Size, kDa	365	365	365	150	150	150
Valency
CD20	4	2	6	2	2	0
CD22	2	4	0	0	0	2
Rapid internalization	No	Yes	No	No	No	Yes
Off-rate* (Raji)	0.54	0.95	0.36	1.0	2.5†	ND
In vitro growth inhibition (EC50, nM)
Daudi	0.33	0.5	0.15‡	> 15 (+GAH = 1.7)	> 15	None
Raji	0.32	3.5	0.07‡	> 15 (+GAH = 1.0)	> 15	None
Ramos	0.20	1.6	0.15‡	> 15 (+GAH = 0.5)	> 15	None
B-cell depletion	Moderate	Moderate	Moderate	Strong	Strong†	Moderate
Apoptosis (Daudi, % annexin+)
−GAH	23.2	25.5	16.9	10.6	17.7	13.7
+GAH	ND	ND	ND	14.0	16.0	ND
Ca2+ mobilization
−GAH	None	None	None‡	None‡	None‡	None
+GAH	Weak	Weak	Weak‡	Moderate‡	Moderate‡	None
CDC	No	No	No‡	Yes	Yes	No
ADCC	Moderate	Strong	Strong‡	Strong	Strong	Weak
Trafficking to lipid rafts
CD22	Enhanced	Enhanced	No	No	No	Yes
CD20	Yes	Yes	Yes	Yes	Yes	No
Homotypic adhesion	Strong	Strong	Moderate	No	No	No
Serum stability§	5 days§	5 days§	11 days‖	11 days‖	ND	ND

GAH indicates goat anti–human Fc crosslinking antibody; and ND, not done.

^*Off-rate shown as the quotient of the T_1/2 of the test article divided by T_1/2 of v-mab.

^†Data from Goldenberg et al.³¹

^‡Data from Rossi et al.⁹

^§No change from day 0 by bispecific ELISA.

^‖A total of 85% compared with day 0 by ELISA.