Boundless Bio, a clinical-stage, next-generation precision oncology company interrogating extrachromosomal DNA (ecDNA) biology to deliver transformative therapies to patients with previously intractable oncogene amplified cancers, today announced multiple upcoming poster presentations at the American Association for Cancer Research (AACR) Annual Meeting 2024, which is being held April 5-10, 2024, in San Diego, CA.

Details of the presentations are as follows:

Title: Oral CHK1 inhibitor BBI-355 allows flexibility of dose and schedule with demonstration of monotherapy and combinational antitumor activity in extrachromosomal DNA (ecDNA) driven preclinical models

Abstract Number: 613

Session Category: Experimental and Molecular Therapeutics

Session Title: Kinase and Phosphatase Inhibitors 1

Session Date and Time: Sunday Apr 7, 2024, 1:30 PM - 5:00 PM PT

Location: Poster Section 25

Poster Board Number: 23

Title: Preclinical and clinical pharmacodynamic characterization of BBI-355, a novel, orally bioavailable, and selective CHK1 inhibitor being evaluated in the first-in-human Phase 1/2 POTENTIATE clinical trial of patients with cancer harboring oncogene amplifications

Abstract Number: 3631

Session Category: Clinical Research

Session Title: Biomarkers in Clinical Trials

Session Date and Time: Monday Apr 8, 2024, 1:30 PM - 5:00 PM PT

Location: Poster Section 40

Poster Board Number: 9

Title: ecDNA-based amplification of multi-drug resistance genes leads to acquired resistance to taxane-based chemotherapy

Abstract Number: 5870

Session Category: Experimental and Molecular Therapeutics

Session Title: Mechanisms of Drug Resistance 3

Session Date and Time: Tuesday Apr 9, 2024, 1:30 PM - 5:00 PM PT

Location: Poster Section 24

Poster Board Number: 14

About BBI-355

Boundless Bio’s lead ecDNA-directed therapy (ecDTx), BBI-355, is a novel, oral, selective inhibitor of checkpoint kinase 1 (CHK1) being studied in the ongoing, first-in-human, Phase 1/2 POTENTIATE clinical trial (NCT05827614) in patients with oncogene amplified cancers. CHK1 is a master regulator of cells’ response to replication stress (RS). RS is elevated in ecDNA-enabled oncogene amplified cancer cells and, because of this, represents a key vulnerability of those cells. BBI-355 was designed to exploit the elevated RS in ecDNA-enabled oncogene amplified cancer cells by disrupting proper CHK1 function in regulating RS and thereby facilitating catastrophic RS to preferentially kill cancer cells relative to healthy cells.

About Boundless Bio

Boundless Bio is a clinical-stage oncology company dedicated to unlocking a new paradigm in cancer therapeutics to address the significant unmet need of patients with oncogene amplified tumors by targeting extrachromosomal DNA (ecDNA), a root cause of oncogene amplification and observed in more than 14% of cancer patients. Boundless Bio is developing the first ecDNA-directed therapy (ecDTx), BBI-355, which is an oral inhibitor of checkpoint kinase 1 (CHK1) and is being evaluated in a Phase 1/2 clinical trial in patients with oncogene amplified cancers Boundless Bio’s second ecDTx, BBI-825, is an oral inhibitor of ribonucleotide reductase (RNR) and recently entered a Phase 1/2 clinical trial in cancer patients with resistance gene amplifications. Leveraging its Spyglass platform, Boundless Bio has additional programs advancing through preclinical development and discovery. Boundless Bio is headquartered in San Diego, CA.

For more information, visit www.boundlessbio.com.

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