Xencor, Inc. reported updated results from the Phase 1 study of its candidate XmAb819, an ENPP3 x CD3 T-cell engaging bispecific antibody, in patients with advanced clear cell renal cell carcinoma (ccRCC). The company filed an 8-K on October 25, 2026, which included a presentation and press release detailing the findings.
The presentation highlighted that XmAb819 is an XmAb® 2+1 format designed to selectively bind and kill high-density ENPP3 tumor cells while sparing normal tissues. Preclinical data showed strong in vivo activity in a PD1-refractory model of ccRCC. The company also noted that XmAb819 has a well-characterized pharmacokinetic profile with a terminal half-life of approximately 8 days, supporting a dosing schedule of every two weeks.
Regarding the clinical trial, the Phase 1 study (NCT05433142) enrolled patients with relapsed or refractory ccRCC who had previously received immune checkpoint inhibitors and tyrosine kinase inhibitors. The study evaluated eight dose levels below the expansion cohort, with a total of 51 patients in the dose escalation phase. The patient characteristics included a median age of 61 years, with 81.5% of patients being male. The majority of patients had an intermediate risk score according to the IMDC criteria, and 13.4% of patients had sarcomatoid features.
In terms of financial outlook, Xencor stated that, based on current operating plans, it expects to have sufficient cash to fund research and development programs and operations through 2029. The company also outlined its development strategy for XmAb819, which includes initiating a potential registration-enabling study in 2027 for advanced ccRCC and ENPP3+ tumors.
Xencor’s oncology pipeline includes three late-stage programs: Xaluritamig (STEAP1 x CD3) in prostate cancer and Ewing sarcoma, ASP2138 (CLDN18.2 x CD3) in gastric and pancreatic cancer, and XmAb819 (ENPP3 x CD3) in ccRCC. The company emphasized its focus on clinical excellence to realize value from its XmAb® platform.
