Table 4.

In vitro profile of 4 sequenced optimized variants. Clinical candidate, BI 655066, showed highest affinity and functional potency against human and cynomolgus IL23 induced IL17 production in the mouse splenocytes assay. To evaluate non-specific binding to irrelevant serum proteins an interference assay was performed demonstrating no change in the on-rate of the antibodies binding to IL23 in the presence of serum, indicating no non-specific binding

Parameter / Assay	BI 655066	BI 655067	BI 655068	BI 655069
Kd human IL23 (pM)	< 10	< 10	15	36
Kd cynomolgus IL23 (pM)	< 10	< 10	<10	16
Serum Interference [kon(serum)/kon(buffer)]	1.2	1.2	1.0	1.2
Inhibition of endogenous (THP-1 cell generated) human IL23-induced IL17 production (IC50, pM)	2	7	43	216
Inhibition of recombinant cynomolgus IL23-induced IL17 production (IC50, pM)	17	54	145	665