Company: DAWN
Filing Date: 2025-02-25
Form Type: 10-K
Source: 0000950170-25-026654
Chunk: 60

Company: Day One Biopharmaceuticals, Inc.
Filing Date: 2025-02-25
Form: 10-K
Item: Item 1
Chunk 60
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 of OJEMDA in the United States. OJEMDA is the only systemic therapy for pLGG that offers once-weekly dosing, with or without food, as a tablet or oral suspension.

The accelerated approval of OJEMDA is based on data from the Company’s pivotal open-label Phase 2 trial, or FIREFLY-1, which enrolled a total of 137 relapsed or refractory BRAF-altered pLGG patients across two study arms. Arm 1, which accrued 77 patients, was used for the efficacy analyses. Arm 2 provided additional safety data from an incremental 60 patients and was initiated to enable access to OJEMDA once Arm 1 had fully accrued. Details of this trial were presented in November 2023 at the Society for Neuro-Oncology meeting through two oral plenary presentations and in parallel through a publication in Nature Medicine.

The approval of OJEMDA was based, in part, on the major efficacy outcome measure of overall response rate, or ORR, defined as the proportion of patients with complete response, partial response, or PR, or minor response, or MR, by independent review based on Response Assessment in Pediatric Neuro-Oncology Low-Grade Glioma, or RAPNO LGG.

In Arm 1, data from the 76 RAPNO LGG evaluable patients include:

•A best ORR of 51% (95% CI: 40 - 63), which included 28% PRs and 11% MRs.

•The ORR for OJEMDA was 52% among the 64 patients with BRAF fusions or rearrangements and 50% for the 12 patients with a BRAF V600 mutation.

•The ORR was 49% among the 45 patients who had received a prior MAPK-targeted therapy, and 55% among the 31 patients who had not received a prior MAPK-targeted therapy.  

•As of the June 5, 2023 data cutoff, the median duration of response by RAPNO LGG was 13.8 months (95% CI: 11.3, not estimable). In addition, 66% of patients remained on study and continue on treatment as of the cutoff date.

1

•The median time to response, following initiation of treatment, with OJEMDA was 5.3 months (range 1.6 months, 11.2 months).

•