Ono Pharma Announces an Oral Presentation on Phase 2 Data for Tirabrutinib and a Poster Session on ONO-4578 (EP4 Antagonist) at the American Society of Clinical Oncology (ASCO) Annual Meeting

• Positive data from the Phase 2 PROSPECT Study of tirabrutinib in U.S. patients with relapsed or refractory primary central nervous system lymphoma (PCNSL) will be presented in a rapid oral session.
• Data on the neoadjuvant ONO-4578 (EP4 antagonist) in combination with nivolumab for rectal cancer will be presented in a poster session.

Ono Pharmaceutical Co., Ltd. (Headquarters: Osaka, Japan; President and COO: Toichi Takino; “ONO”) announced that it will present positive results from the Phase 2 PROSPECT study of tirabrutinib (ONO-4059) for the treatment of relapsed or refractory primary central nervous system lymphoma during an oral presentation at the Annual Meeting of the American Society of Clinical Oncology (ASCO) being held May 30 to June 3, 2025, in Chicago, Illinois. The company will also present data on ONO-4578, an investigational EP4 antagonist, for the treatment of locally advanced resectable rectal cancer, during a poster presentation.

"We are fully committed to developing innovative drugs for cancer patients. This announcement is an important step forward in demonstrating that we can potentially provide new value to patients,” said Tatsuya Okamoto, Corporate Officer / Executive Director, Clinical Development at ONO. “We aim to offer new treatment options in cancer care globally and contribute to improving patients' quality of life."

Details for both studies and data to be presented are as follows:

Tirabrutinib (ONO-4059)

Abstract Title: Tirabrutinib for the treatment of relapsed or refractory primary central nervous system lymphoma: Efficacy and safety from the phase II PROSPECT study.

Abstract Submission ID: 487376

Session Type and Title: Rapid Oral Abstract – Central Nervous System Tumors

Session Date and Time: May 31, 2025, 3:00-4:30 PM CDT

Presenter: Lakshmi Nayak, MD, Dana-Farber Cancer Institute

ONO-4578

Abstract Title: Neoadjuvant ONO-4578, an EP4 antagonist, in combination with nivolumab after chemoradiation therapy in locally advanced resectable rectal cancer.

Session Type and Title: Poster Session Gastrointestinal Cancer – Colorectal and Anal

Abstract Number for Publication: 3588

Poster Board: 257

Session Date and Time: May 31, 2025, 9:00 AM-12:00 PM CDT

Presenter: Yusuke Takahashi, Lower Gastrointestinal Surgery, National Hospital Organization Osaka National Hospital

About Ono Pharmaceutical Co., Ltd

Ono Pharmaceutical Co., Ltd. delivers innovative therapies for patients worldwide. Upholding its philosophy of “Dedicated to the Fight against Disease and Pain,” Ono targets areas with unmet medical needs including oncology, immunology, and neurology, and fosters partnerships with academic and biotech organizations to accelerate drug discovery. Through its affiliate, Deciphera Pharmaceuticals, Ono is accelerating clinical development and commercial operations in the US and Europe to drive global business expansion and further its commitment to patient care. For more information, please visit the company's website at https://www.ono-pharma.com/en.

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