# Day One Biopharmaceuticals (Servier)

Source: https://onco.cc/companies/day-one-biopharmaceuticals/  
OnCo record `day-one-biopharmaceuticals` (Company). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Paediatric-first oncology company whose tovorafenib became the first targeted therapy approved for childhood low-grade glioma driven by BRAF fusions, following dabrafenib with trametinib (2023) for BRAF V600E tumours. Servier bought it in April 2026.

## Summary

Day One Biopharmaceuticals, based in Brisbane, California, and formerly listed as DAWN, is a paediatric-first oncology company whose tovorafenib became the first targeted therapy approved for childhood low-grade glioma driven by BRAF fusions, following dabrafenib with trametinib (2023) for BRAF V600E tumours. Ojemda, its brand of tovorafenib, was approved in the United States in 2024 on the FIREFLY-1 trial, Ipsen holds the rights outside the United States, the LOGGIPY-2 phase 3 tests it in the first-line setting, and pimasertib, a MEK inhibitor, is being developed in combinations. OnCo links it to glioma and paediatric low-grade glioma and to the bottleneck of rare and paediatric cancers without markets, which its model of developing drugs for children first is meant to answer. In January 2026 it completed the purchase of Mersana Therapeutics, adding the antibody-drug conjugate emiltatug ledadotin for adenoid cystic carcinoma, and on 23 April 2026 Servier completed its acquisition of Day One for 21.50 dollars a share in cash, about 2.5 billion dollars in equity value. Whether a paediatric-first programme keeps its priority inside a larger company is the open question now. Tovorafenib has its own page.

## Fields

- Kind: Company
- Last checked: 2026-10-29
- HQ: Brisbane, CA
- Type: biotech
- Website: https://www.dayonebio.com

## Notes

- Checked 29 October 2026. Servier's acquisition is from Day One's Form 8-K of 23 April 2026 (completion, 21.50 dollars a share, approximately 2.5 billion dollars equity value, Nasdaq delisting). The Mersana purchase closed on 6 January 2026 at 25 dollars a share in cash plus a contingent value right of up to 30.25 dollars, per Day One's release. dayonebio.com still resolves but refused an automated request on 29 October 2026.

## Sources

- Official website: https://www.dayonebio.com
- Completion of the Servier acquisition, Form 8-K (SEC): https://www.sec.gov/Archives/edgar/data/1845337/000119312526171997/d27888d8k.htm
- Day One completes acquisition of Mersana Therapeutics: https://www.biospace.com/press-releases/day-one-completes-acquisition-of-mersana-therapeutics

## Connected records

- cancers: [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/), [Paediatric low-grade glioma](https://onco.cc/cancers/paediatric-low-grade-glioma/)
- drugs: [Tovorafenib](https://onco.cc/drugs/tovorafenib/)
- companies: [Mersana Therapeutics](https://onco.cc/companies/mersana/), [Servier](https://onco.cc/companies/servier/)
- trials: [A Study of Emiltatug Ledadotin (Emi-Le) in Participants With Solid Tumors](https://onco.cc/trials/nct05377996/), [DAY101 vs. Standard of Care Chemotherapy in Pediatric Participants With Low-Grade Glioma Requiring First-Line Systemic Therapy (LOGGIC/FIREFLY-2)](https://onco.cc/trials/nct05566795/), [FIREFLY-1](https://onco.cc/trials/firefly-1/)
- bottlenecks: [Rare and paediatric cancers without markets](https://onco.cc/bottlenecks/b-rare-cancers/)
- roadmaps: [Paediatric oncology roadmap: cooperative-group cures → engineered immunity → drugs developed for children first](https://onco.cc/roadmaps/paediatric-oncology-roadmap/)

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