Day One Biopharmaceuticals (DAWN) investor relations material

Strategic focus and portfolio overview

• Emphasis on developing transformative targeted therapies for life-threatening diseases, especially cancer, with a strong commitment to pediatric and adult populations.

• OJEMDA, approved in April 2024 for relapsed/refractory pediatric low-grade glioma (PLGG), has exceeded launch expectations and driven significant growth.

• Pipeline includes Day 301, a PTK7-targeted ADC in phase I, and the planned acquisition of Mersana Therapeutics for the Emi-Le ADC program targeting adenoid cystic carcinoma (ACC).

OJEMDA launch and market evolution

• OJEMDA addresses a major unmet need in relapsed PLGG, where no clear standard of care existed post-chemotherapy.

• Approved for BRAF-altered tumors, aiming to become the standard in second-line and beyond; MEK inhibitors are used off-label but lack robust data.

• Launch success attributed to strong reimbursement access and positive physician experiences, with additional data sets driving adoption.

Clinical data and physician adoption

• Two-year and three-year follow-up data highlight OJEMDA’s efficacy, safety, and positive impact on growth velocity, addressing key concerns.

• Three-year data show 77% of patients completing 24 months of treatment did not require further systemic therapy a year after stopping.

• Retreatment with OJEMDA is effective, and real-world treatment durations align with clinical trial results.

• Physician conviction correlates with experience; high-volume prescribers are strong advocates, while less experienced physicians rely on personal benchmarks.