Understanding Biomarkers in Modern Oncology

In the current era of precision medicine, oncology clinicians frequently use prognostic vs predictive biomarkers to guide complex treatment decisions. For instance, circulating tumor DNA (ctDNA) helps monitor relapse risks or detect early progression. However, significant confusion persists regarding the utility of these markers at both the individual and clinical trial levels. This distinction is vital because a misunderstanding can lead to incorrect clinical inferences or misguided regulatory choices. Therefore, medical professionals must clearly differentiate between these two categories to optimize patient outcomes.

Clinical Utility of Prognostic vs Predictive Biomarkers

A prognostic biomarker provides essential information about the likely patient health outcome regardless of the therapy. Conversely, a predictive biomarker indicates the specific benefit a patient might receive from a particular treatment. Recent FDA reviews of the DESTINY-Breast11, SERENA-6, and IMvigor011 trials emphasize this complexity. While the FDA approved Enhertu based on pathological complete response (pCR) in DESTINY-Breast11, the SERENA-6 trial faced a different fate. Specifically, the Oncology Drug Advisory Committee (ODAC) voted against approval for camizestrant. They argued that the clinical benefit of switching therapy based on early ESR1 detection remained unproven. Consequently, identifying a marker as purely prognostic versus predictive is critical for validating surrogate endpoints in clinical trials.

Surrogate Endpoints and Regulatory Decisions

Surrogate markers like ctDNA are transforming trial designs. The IMvigor011 trial demonstrated that atezolizumab significantly benefits patients with detectable ctDNA after surgery. This trial successfully used a biomarker-informed approach to refine patient selection. However, the SERENA-6 results highlight that simply detecting a mutation does not always predict a superior outcome from early intervention. Furthermore, clinical practice should only change when a biomarker is strong enough to serve as a reliable surrogate for overall survival. Clinicians should remain cautious when interpreting new biomarker data to ensure they reflect true clinical benefits for their patients.

Frequently Asked Questions

How do prognostic biomarkers differ from predictive ones?

Prognostic biomarkers provide information about the natural course of a disease. In contrast, predictive biomarkers identify patients more likely to respond to a specific therapeutic intervention.

Why did the ODAC vote against the SERENA-6 trial?

The committee questioned if switching therapy upon ESR1 detection provided a clinically meaningful benefit compared to waiting for standard radiographic progression.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or a substitute for professional healthcare consultation. Refer to the latest local and national guidelines for clinical practice.

References

Pabani A et al. Critical Appraisal: Prognostic versus Predictive Surrogate Markers in Oncology. J Natl Cancer Inst. 2026 Jun 02. doi: undefined. PMID: 42226017.

U.S. Food and Drug Administration. Oncology Drug Advisory Committee Meeting Materials: SERENA-6 and Camizestrant. April 30, 2026.

AstraZeneca. Update on FDA Advisory Committee vote on camizestrant in combination with a CDK4/6 inhibitor. April 2026.