From Scientific Hypothesis to Clinical Practice: The Next Chapter for CLDN18.2

Biotech From Scientific Hypothesis to Clinical Practice: The Next Chapter for CLDN18.2 Oct 19, 2026 8:00am Biotech A decade ago, CLDN18.2 was a promising scientific hypothesis. Today, it is one of the most closely watched targets in cancer research, with growing interest across gastrointestinal and other solid tumors.Few organizations have had a closer view of that journey than Astellas. Over ten years, Astellas has helped move CLDN18.2 from biological potential to clinical practice, building a depth of experience and evidence that uniquely positions the company to help answer the questions shaping the treatment of solid tumors.As the CLDN18.2 field matures, the conversation is moving beyond establishing efficacy to addressing a broader set of clinical questions, including patient identification, testing, disease monitoring, treatment sequencing and implementation in practice.

CLDN18.2 – the discovery that sparked a decade of progressBefore CLDN18.2 became a validated target, it was simply an intriguing scientific observation.In the early 2010s, researchers found that, while largely hidden within the cell membrane in healthy tissues, CLDN18.2 was exposed on the surface of tumor cells in a substantial proportion of gastrointestinal cancers. This observation raised an important question: could this protein become a clinically meaningful target?Astellas saw potential not only in the biology, but also in what it might ultimately mean for people facing cancers with historically limited treatment options. This conviction led the company to acquire Ganymed in 2016 and accelerate investment in CLDN18.2 research.

What began as an emerging scientific hypothesis has since evolved into an important area of biomarker-driven oncology research and clinical practice.Turning possibility into practiceRecognizing the potential of the science was one thing. Translating that scientific potential into clinical practice was another.Progress required more than demonstrating efficacy. Physicians, pathologists and healthcare systems needed practical experience of testing, identifying eligible patients and incorporating a new biomarker-driven approach into clinical decision-making, particularly at first diagnosis.Those early experiences helped establish the foundations for CLDN18.2 biomarker-driven care, building clinical expertise, infrastructure and physician networks needed to support implementation, while identifying opportunities to strengthen care pathways.“The CLDN18.2 story shows what it takes to turn promising biology into meaningful patient impact.

The field has evolved from scientific hypothesis to clinical reality. The opportunity now is to build on those insights and broaden the reach of CLDN18.2-directed innovation to help more patients benefit,” shares Moitreyee Chatterjee-Kishore, Head of Oncology Development, Astellas Pharma Inc. Finding the right patientsPatient identification is not simply a yes-or-no exercise.

Increasingly, clinicians are looking beyond whether a biomarker is present to how testing, interpretation and clinical decision-making can work together most effectively to support patient care.Expression levels vary from patient to patient, testing needs to happen at first diagnosis and quickly enough to inform treatment decisions, results need to be understood and applied consistently, and healthcare systems need specific support to embed biomarker-driven innovation. “One of the biggest shifts in the field has been moving from understanding the biology of CLDN18.2 to understanding how it can inform clinical practice, through the adoption of a more targeted approach in managing gastric cancer. Ensuring the right information, especially real-world evidence continues to reach clinicians at the right time will remain an important part of the next phase of progress.

At the same time, continued research into CLDN18.2 across other solid tumors could help broaden its potential impact for patients,” said Emad Siddiqui, Head of Medical Affairs Global Brand Strategy, Astellas. Testing pathways have to work within the realities of clinical practice, where tissue availability, timing of testing and coordination across multidisciplinary teams to provide the results can all affect whether biomarker information is available when it is needed.Broadening the possibilitiesHow can CLDN18.2-directed innovation reach additional patient populations, treatment settings and tumor types? Could different therapeutic approaches address different clinical needs, particularly across CLDN18.2 expression levels?Astellas is exploring these questions through a broad investigational pipeline, applying different therapeutic modalities to advance understanding of CLDN18.2 across patient populations and treatment settings.

This includes investigational bispecifics and antibody-drug conjugates, with programs spanning early-stage research through to Phase 3 development.“The future of CLDN18.2 will not be defined by a single approach. Different modalities offer different ways to explore the biology and address specific unmet needs. As the landscape expands, clinicians will increasingly need evidence to help inform treatment sequencing, disease monitoring and long-term patient management.

Our ambition is to apply what we have learned to help unlock new possibilities for patients,” concluded Moitreyee. After ten years in the field, Astellas remains focused on generating the clinical, biomarker and real-world evidence needed to help answer emerging CLDN18.2 questions and support the continued evolution of biomarker-driven care. With the ambition of expanding the possibilities for patients living with some of the hardest-to-treat cancers, the company is working to help shape the next chapter of CLDN18.2-directed innovation.

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