Day One Appoints Michael Vasconcelles, M.D., as Head of Research and Development

Dr. Michael Vasconcelles brings more than 25 years of extensive oncology research, development and health technology expertise and corporate executive leadership to Day One

Dr. Vasconcelles to drive pipeline creation and execution

BRISBANE, Calif., June 10, 2025 (GLOBE NEWSWIRE) -- Day One Biopharmaceuticals, Inc. (Nasdaq: DAWN) (“Day One” or the “Company”), a biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced that Michael Vasconcelles, M.D., has joined the Company as Head of Research & Development (R&D).

“We are thrilled to welcome Mike during this pivotal time at Day One. As an accomplished biopharmaceutical executive with more than 25 years of experience in building businesses and leading teams in oncology therapeutic development, commercialization and health technology, Mike will be an outstanding addition to our leadership team,” said Jeremy Bender, Ph.D., chief executive officer of Day One. “Mike will be instrumental in supporting our ongoing medical and scientific strategies to drive OJEMDA’s growth while also continuing to build our pipeline of first- or best-in-class medicines for patients of all ages with life-threatening diseases.”

As Head of R&D and a member of the Executive Leadership Team, the Company’s research, development and medical affairs infrastructure will report to Dr. Vasconcelles.

Dr. Vasconcelles’ experience spans more than 25 years in oncology research and development as an academic hematologist/oncologist and as an industry leader at both large pharmaceutical and emerging biotechnology companies. Most recently, he was the Executive Vice President and Head of Research, Development, and Medical Affairs at ImmunoGen. He was instrumental in transforming the company from primarily a clinical development and U.S.-focused commercial stage organization to a vertically integrated, global biotech enterprise. This transformation was accomplished through reinvestment in ImmunoGen’s research infrastructure, and the globalization of product launch and lifecycle management investment to optimize the commercialization of ELAHERE^® (. Prior to ImmunoGen, he served as Chief Medical Officer and Head of the Medical and Scientific Organization at Flatiron Health, a subsidiary of the Roche Group. Prior to Flatiron Health, Dr. Vasconcelles was Chief Medical Officer at Unum Therapeutics after leading the Oncology Therapy Area Unit at Takeda for several years. Earlier in his career, he oversaw the clinical development of Genzyme’s transplant and oncology portfolio as Group Vice President and Global Therapeutic Area Head of Transplant and Oncology. Following Sanofi’s acquisition of Genzyme, he led Personalized Medicine and Companion Diagnostics at Sanofi Oncology.

“I’m excited to join Day One at such a critical moment in its growth. The company has been built on a bold vision to deliver transformative therapies for children with cancer and is extending its unwavering commitment to scientific excellence into this new chapter with its vision of bringing transformative medicines to patients of all ages. Having previously developed medicines for childhood leukemia, Day One’s vision deeply resonates with me,” said Michael Vasconcelles, M.D. “I look forward to supporting OJEMDA, advancing the existing pipeline, and expanding the portfolio, working with the team to lead the organization through its next stage of growth, and impact.”

In addition to Dr. Vasconcelles’ new role as Head of Research and Development at Day One, he continues to serve as an Independent Director at Kura Oncology Inc. and Molecular Partners AG. Dr. Vasconcelles earned both his B.A., and M.D., from Northwestern University, where he serves on the Executive Committee of the Medical Alumni Association for the Feinberg School of Medicine. During the period from 1996-2021, Dr. Vasconcelles held a faculty appointment at the Harvard Medical School, where he completed all of his postgraduate training, and was an associate physician at the Beth Israel Hospital, the Brigham and Women’s Hospital and the Dana-Farber Cancer Institute.

About Day One Biopharmaceuticals

Day One Biopharmaceuticals believes when it comes to pediatric cancer, we can do better. The Company was founded to address a critical unmet need: the dire lack of therapeutic development in pediatric cancer. Inspired by “The Day One Talk” that physicians have with patients and their families about an initial cancer diagnosis and treatment plan, Day One aims to re-envision cancer drug development and redefine what’s possible for all people living with cancer—regardless of age—starting from day one.

Day One partners with leading clinical oncologists, families, and scientists to identify, acquire, and develop important targeted cancer treatments. The Company’s pipeline includes tovorafenib (OJEMDA™) and DAY301.

Day One is based in Brisbane, California. For more information, please visit  or find the Company on  or .

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Cautionary Note Regarding Forward-Looking Statements

This press release contains “forward-looking” statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, including, but not limited to: Day One’s plans to develop and commercialize cancer therapies, expectations from current and planned clinical trials, the execution of the Phase 2 and Phase 3 clinical trial for tovorafenib as designed, expectations with respect to the timing of Day One’s Phase 1a/b clinical trial of DAY301, any expectations about safety, efficacy, timing and ability to complete clinical trials, release data results and to obtain regulatory approvals for tovorafenib and other candidates in development, and the ability of tovorafenib to treat pLGG or related indications.

Statements including words such as “believe,” “plan,” “continue,” “expect,” “will,” “develop,” “signal,” “potential,” or “ongoing” and statements in the future tense are forward-looking statements. These forward-looking statements involve risks and uncertainties, as well as assumptions, which, if they do not fully materialize or prove incorrect, could cause our results to differ materially from those expressed or implied by such forward-looking statements.

Forward-looking statements are subject to risks and uncertainties that may cause Day One’s actual activities or results to differ significantly from those expressed in any forward-looking statement, including risks and uncertainties in this press release and other risks set forth in our filings with the Securities and Exchange Commission, including Day One’s ability to develop, obtain and retain regulatory approval for or commercialize any product candidate, Day One’s ability to protect intellectual property, the potential impact of global business or macroeconomic conditions, including as a result of inflation, changing interest rates, cybersecurity incidents, significant political or regulatory developments or changes in trade policy, including tariffs or shifting priorities within the U.S. Food and Drug Administration, global regional conflicts and the sufficiency of Day One’s cash, cash equivalents and investments to fund its operations. These forward-looking statements speak only as of the date hereof and Day One specifically disclaims any obligation to update these forward-looking statements or reasons why actual results might differ, whether as a result of new information, future events or otherwise, except as required by law.

DAY ONE MEDIA

Laura Cooper, Head of Communications

DAY ONE INVESTORS

LifeSci Advisors, PJ Kelleher