XmAb819

August 2026: Xencor (NASDAQ: XNCR) provided a multi-program catalyst update. XmAb819 (ENPP3 x CD3) in advanced clear cell renal cell carcinoma had Phase 1 results accepted for a proffered oral presentation at ESMO 2026 (October 23-27, Madrid), focused on IV expansion cohorts at doses being evaluated as recommended Phase 3 doses; a registration-enabling monotherapy study in advanced ccRCC is on track for 2027. Subcutaneous dose escalation is ongoing, a post-nivolumab/ipilimumab ccRCC sub-study is planned to open in 3Q26, an anti-PD1 combination sub-study is planned, and an ENPP3+ colorectal cancer/NSCLC/papillary RCC sub-study began enrollment in 2Q26.

XmAb541 (CLDN6 x CD3) monotherapy showed approximate ORR of 14% in ovarian cancer and 28% in germ cell tumors at the putative RP3D (60 mg every 3 weeks); higher doses showed possible added activity but reversible hearing impairment limited exposure. Grade 1/2 CRS at the putative RP3D was about 14%/17%, with no Grade 3+ CRS. FDA granted Fast Track in July 2026 for relapsed/refractory germ cell tumors after platinum therapy. Development is being prioritized in combination with XmAb808 (B7-H3 x CD28); combination dose escalation is ongoing and expected to reach target dose range in 2027.

XmAb942’s Phase 2b XENITH-UC in ulcerative colitis remains on track for a blinded interim analysis around year-end 2026 and the 12-week primary endpoint in 2H27. XmAb412 (TL1A x IL23p19) entered first-in-human Phase 1 in 3Q26, with initial data planned in 1H27. Plamotamab in RA and XmAb657 in autoimmune indications are each expected to have Phase 1 updates in 2H26. Separately, Xencor said Alexion will pay $105 million under a July 2026 Ultomiris royalty settlement, and Zenas’ May 2026 BLA submission for obexelimab in IgG4-related disease triggered a $10 million milestone.