Immunogenicity
Thirty-eight patients were considered evaluable for ADAs to BGB-A333 (treatment-emergent ADAs) as they had a baseline and ≥1 post-baseline ADA result. The incidence of treatment-emergent ADAs across all phases was 18.4% (7/38), with three patients (7.9%) testing positive for neutralising antibodies. No patients showed evidence of treatment-boosted ADAs. Of the seven patients with treatment-induced ADAs, four had persistent ADA responses (4/38; 10.5% of evaluable patients). There was no apparent effect of immunogenicity on the BGB-A333 PK profile (data not shown).The incidence of ADAs to tislelizumab (treatment-emergent ADAs) in Phase 1b and Phase 2 (combination dose expansion) was 21.7% (5/23 evaluable patients who had baseline and ≥1 post-baseline ADA results), with two patients (8.7%) testing positive for neutralising antibodies. No patients showed evidence of treatment-boosted ADAs. Of the five patients with treatment-induced ADAs, two had persistent ADA responses (2/23; 8.7% of evaluable patients).