Day One Biopharmaceuticals (NASDAQ:DAWN), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for patients of all ages with genomically-defined cancers, today announced that the first patient has been dosed in a Phase 2 clinical trial evaluating DAY101 as a monotherapy in patients with RAF-altered solid tumors. DAY101 is an investigational, oral, brain-penetrant, highly-selective type II pan-RAF kinase inhibitor designed to target a key enzyme in the MAPK signaling pathway.
“DAY101 has demonstrated encouraging anti-tumor activity as a monotherapy in patient populations where MAPK pathway alterations are believed to play an important role in driving disease progression,” said Samuel Blackman, M.D., Ph.D., co-founder and chief medical officer of Day One. “Expanding the development of DAY101 beyond pediatric low-grade glioma represents an important step in our overall development strategy for this promising program, and we look forward to enrolling additional RAF-altered solid tumor patients in this Phase 2 monotherapy study.”
The multi-center, open-label umbrella study, FIRELIGHT-1, will evaluate the safety and efficacy of DAY101 in patients with recurrent or progressive solid tumors with activating RAF alterations. This study will accrue adults as well as adolescent patients as young as 12 years of age. In the Phase 2 monotherapy portion, patients will be enrolled either into a melanoma cohort or a “tissue agnostic” cohort, and will receive oral DAY101 at a dose of 600mg once weekly. The primary endpoint will be overall response rate (ORR) as assessed by RECIST version 1.1 criteria. Secondary and exploratory endpoints include safety, duration of response, progression-free survival, and time to response. Additional information may be found at ClinicalTrials.gov, using Identifier NCT04985604.
Day One expects to initiate a Phase 1b combination portion of the study with the Company’s oral MEK inhibitor, pimasertib, in the first quarter of 2022. Day One also continues to enroll patients in a pivotal Phase 2 clinical trial (FIREFLY-1) of DAY101 in pediatric, adolescent and young adults with recurrent or progressive low-grade glioma (pLGG) harboring a known BRAF alteration (NCT04775485), with initial data expected in the first half of 2022.