CEACAM5 May Become a New Targetable Biomarker in Lung Cancer

CEA, also known as CEACAM5, has long been used in lung cancer as a serum monitoring and prognostic marker, but had not previously been successfully targeted as a therapeutic biomarker until an initial clinical disclosure of BG-C477, a novel antibody drug conjugate.¹

Matthew Lee, MD, an assistant professor of medical oncology at City of Hope in Duarte, California, who presented findings on a first-in-human phase 1a trial (NCT06596473) assessing BG-C477 in NSCLC at the 2026 European Society for Medical Oncology (ESMO) Congress, spoke with CancerNetwork^® about what he wants practicing oncologists to take away from this first disclosure of BG-C477 data.

The confirmed overall response rate (ORR) with BG-C477 among 43 evaluable patients in the overall NSCLC population was 37.2% (95% CI, 23.0%-53.3%), which included 16 partial responses. Among patients with high CEA expression per central laboratory evaluation, the confirmed ORR was 60.0% (95% CI, 38.7%-78.9%), which included 15 partial responses across different histological subtypes and EGFR mutation status. Data showed that the median progression-free survival was not reached at the time of analysis.

Transcript:

CancerNetwork: What should practicing oncologists to take away from this first disclosure of BG-C477 data, given how early and hypothesis-generating a dose-escalation cohort is?

Lee: One of the key points is that CEA has been looked at historically in lung cancer, but it hasn’t really been targeted in a successful, efficacious, and safe way until this point. This is promising in terms of the design of the drug, its safety and tolerability, and even the preliminary efficacy, which really does hold some promise that CEACAM5 can be a potential new biomarker in lung cancer.

We knew about MET and HER2 in the past, and we’ve had some familiarity with CEA, but mainly in the serum, not as a way of targeting. We’ve been using it as a monitoring and prognostic [marker]. This is the first time we can try to target through protein expression by IHC and see some actual efficacious benefit.

Reference

Lee M, Gong Y, Fu S, et al. BG-C477, a CEA (CEACAM5)-targeting antibody-drug conjugate, in patients with advanced non-small cell lung cancer: results from a phase 1a dose-escalation and safety-expansion study. Presented at: European Society for Medical Oncology (ESMO) Congress 2026; October 23-27, 2026; Madrid, Spain. Abstract 2567P.