At ESMO 2026, BeOne Medicines presented first-in-human data for BG-C477, an antibody-drug conjugate targeting CEACAM5 in non-small cell lung cancer. The dataset focused on monotherapy during dose escalation, using retrospective assessment of tumor CEACAM5 expression via a central lab. The company reported 43 patients treated as of April 9, 2026, with a median follow-up of 4.2 months and a median of three prior lines. The confirmed response rate was 56.0% in CEACAM5-high patients versus 5.6% in CEACAM5-low patients, with grade 3 or higher adverse events in 44.2% and no treatment-related deaths. CEACAM5 is a tumor marker tested routinely in clinical settings, and BG-C477 uses an anti-CEACAM5 antibody carrying a topoisomerase I inhibitor payload. BeOne framed the presentation as a new target first-in-human signal at the meeting.