On August 7, 2023 Day One Biopharmaceuticals (Nasdaq: DAWN) ("Day One" or the "Company"), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, reported its second quarter 2023 financial results and highlighted recent corporate achievements (Press release, Day One, AUG 7, 2023, View Source [SID1234633871]).

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"Day One had a remarkable second quarter, with the initiation of the rolling submission of the tovorafenib NDA, followed by an oral presentation at ASCO (Free ASCO Whitepaper) with updated data that we anticipate will support our regulatory application to the FDA," said Jeremy Bender, Ph.D., chief executive officer of Day One. "The majority of children with relapsed or progressive pLGG need new treatment options. With a strong balance sheet, we believe we are well positioned to achieve our key milestones while working towards expanding our pipeline with other innovative therapies."

Program Highlights

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On June 4, 2023, Day One announced new clinical data from the registrational Phase 2 FIREFLY-1 trial evaluating the investigational agent tovorafenib in relapsed or progressive pLGG in an oral presentation at the 2023 ASCO (Free ASCO Whitepaper) Annual Meeting. These new data, with a data cutoff of December 22, 2022, included:

RANO-HGG (n=69) data:

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67% (n=46) ORR by RANO-HGG, the primary endpoint of the trial
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93% CBR (complete response (CR) + partial response (PR)/unconfirmed partial response (uPR) + stable disease (SD))
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6% (n=4) CR
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61% (n=42) PR, including 3 uPR
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26% (n=18) SD
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At the time of data cutoff, the median duration of response (DOR) based on RANO-HGG criteria was not yet reached (95% CI: 9.0 months, not estimable)
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Exhibit 99.1

Among a total of 77 treated patients:

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The median duration of tovorafenib treatment was 10.8 months, with 74% (n=57) of patients on treatment at the time of data cutoff

Safety data, based on the 136 patients treated in both Arm 1 and Arm 2 of FIREFLY-1, indicated monotherapy tovorafenib to be generally well-tolerated. The vast majority of adverse events were Grade 1 or Grade 2, with most common side effects reported related to tovorafenib being change in hair color (71%), fatigue (50%), vomiting (43%), maculopapular rash (41%) and headache (39%). The most commonly reported lab abnormalities were CPK elevation, anemia, hypophosphatemia and AST elevation. Nearly all of the lab abnormalities had no clinical manifestations and did not require clinical intervention or change in study treatment.

The Company also shared the evaluation of responses by Response Assessment in Pediatric Neuro-Oncology Low-Grade Glioma (RAPNO-LGG) and Response Assessment Neuro-Oncology Low-Grade Glioma (RANO-LGG). Those results include:

*RAPNO-LGG data (n=69):

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51% (n=35) ORR by RAPNO-LGG
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25% (n=17) PR including 4 uPR
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26% (n=18) minor response (MR) including 4 unconfirmed MR (uMR)
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36% (n=25) patients with SD
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The median time to response was 5.5 months for confirmed responses
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At the time of data cutoff, Independent Review Committee (IRC)-assessed median DOR based on confirmed RAPNO-LGG responses is 12 months (95% CI: 11.2, not estimable)
*Pending adjudication

RANO-LGG (n=76) data:

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49% (n=37) ORR by RANO-LGG
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26% (n= 20) PR including 8 uPR
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22% (n= 17) MR including 2 uMR
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34% (n=26) patients with SD
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The median time to response was 4.2 months for confirmed responses
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At the time of data cutoff, the IRC-assessed median DOR based on confirmed RANO-LGG responses is 14.4 months (95% CI: 8.4, not estimable)

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Two additional posters were presented on June 5, 2023 during the ASCO (Free ASCO Whitepaper) Pediatric Oncology session, including a trial-in-progress poster for the FIREFLY-2 trial and a poster describing a healthcare resource utilization study conducted for pLGG patients.

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Day One presented two posters at the 2023 American Society of Pediatric Oncology/Hematology Conference on May 10, 2023, focused on the pLGG burden of illness and healthcare utilization data.

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The pivotal Phase 3 FIREFLY-2/LOGGIC clinical trial evaluating tovorafenib as a front-line therapy in patients aged 6 months to 25 years with pLGG continues to enroll in the United States, Canada, Europe, Australia and Asia, with approximately 100 sites planned.
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Exhibit 99.1

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Patient enrollment continues in the Phase 1b/2 FIRELIGHT-1 trials evaluating tovorafenib as a monotherapy and as a combination with the Company’s investigational MEK inhibitor, pimasertib, in adults and adolescents with relapsed, progressive, or refractory solid tumors harboring MAPK pathway aberrations.

Corporate Highlights and Upcoming Milestones

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In June 2023, Day One announced the successful closing of a public offering including the full exercise of the underwriters’ option to purchase additional shares, raising gross proceeds of $172.5 million which strengthens the Company’s balance sheet and extends cash runway into 2026.

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The Company anticipates completing the rolling submission of the tovorafenib NDA by October 2023, following submission of an amended clinical study report (CSR) that will include safety and efficacy data from a planned June 2023 data cutoff.

Second Quarter 2023 Financial Highlights

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Cash Position: Cash, cash equivalents and short-term investments totaled $442.9 million on June 30, 2023. Based on Day One’s current operating plan, management believes it has sufficient capital resources to fund anticipated operations into 2026.

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R&D Expenses: Research and development expenses were $32.2 million for the second quarter of 2023 compared to $22.6 million for the second quarter of 2022. The increase was primarily due to additional employee compensation costs, as well as clinical trial and manufacturing activities related to Day One’s lead product candidate, tovorafenib.

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G&A Expenses: General and administrative expenses were $17.1 million for the second quarter of 2023 compared to $14.2 million for the second quarter of 2022. The increase was primarily due to additional employee compensation costs, as well as the ongoing build-out of commercial capabilities.

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Net Loss: Net loss totaled $45.9 million for the second quarter of 2023 with non-cash stock compensation expense of $9.5 million, compared to $36.5 million for the second quarter of 2022 with non-cash stock compensation expense of $5.6 million.

Upcoming Events

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2023 Wedbush PacGrow Healthcare Conference, August 8-9, 2023

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Morgan Stanley 21st Annual Global Healthcare Conference, September 11-13, 2023

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Exhibit 99.1

About Tovorafenib

Tovorafenib 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, which is being investigated in primary brain tumors or brain metastases of solid tumors. Tovorafenib has been studied in over 325 patients to date. Currently tovorafenib is under evaluation in a pivotal Phase 2 clinical trial (FIREFLY-1) among pediatric, adolescent and young adult patients with relapsed or progressive pLGG, which is an area of considerable unmet need with no approved therapies for the vast majority of patients. The pivotal Phase 3 FIREFLY-2/LOGGIC clinical trial is evaluating tovorafenib as a front-line therapy versus standard of care chemotherapy. Tovorafenib is also being evaluated alone or as a combination therapy for adolescent and adult patient populations with relapsed or progressive solid tumors with MAPK pathway aberrations (FIRELIGHT-1).

Tovorafenib has been granted Breakthrough Therapy and Rare Pediatric Disease designations by the U.S. Food and Drug Administration (FDA) for the treatment of patients with pLGG harboring an activating RAF alteration. Tovorafenib has also received Orphan Drug designation from the FDA for the treatment of malignant glioma, and from the European Commission for the treatment of glioma.