For decades, cancer drug trials have failed at a rate exceeding 95%—burning through $50-60 billion annually on treatments tested in patients who were never likely to respond. On April 17, 2025, researchers from AstraZeneca and Tempus AI published results in Cancer Cell showing that the Predictive Biomarker Modeling Framework (PBMF)—a machine learning system using contrastive learning—can identify, from existing clinical data, which cancer patients will survive longer on immunotherapy versus chemotherapy. Applied retrospectively to completed phase 3 trials, the system improved survival outcomes by 15% compared to traditional patient selection.
Now nearly 10 months later, this approach gains regulatory momentum with the European Society for Medical Oncology (ESMO) releasing in December 2025 the first guidance on validation requirements for AI-based biomarkers (EBAI), establishing standards for clinical implementation and building trust among clinicians and regulators. The implications extend beyond individual drugs: widespread adoption of AI-driven biomarker discovery could fundamentally alter cancer drug economics by enabling precise patient selection before trials begin, potentially rescuing failed therapies through identified responsive subgroups.