Orum Therapeutics (“Orum” or the “Company”) (KRX: 475830), a biotechnology company pioneering the field of degrader antibody conjugates (DACs), today announced that new preclinical data on ORM-1153, a CD123-targeting DAC designed to selectively deliver a proprietary GSPT1-degrading payload for the treatment of acute myeloid leukemia (AML), will be presented at the American Association for Cancer Research® (AACR) Annual Meeting 2026, taking place April 17-22 in San Diego.

Orum’s two posters on ORM-1153 will highlight preclinical efficacy, pharmacology, and non-human primate safety findings that support advancement toward clinical development in AML.

“The data being presented at AACR reflect continued progress for ORM-1153 and Orum’s Dual-Precision TPD²® approach,” said Sung Joo (SJ) Lee, Ph.D., Founder and CEO of Orum. “These preclinical data, including repeat-dose non-human primate studies, support advancement toward clinical development and underscore the potential of our approach to expand the therapeutic window beyond conventional cytotoxic antibody-drug conjugates.”

Orum’s AACR 2026 Presentation Details
Both posters will be presented on Monday, April 20, from 9 am to 12 pm PDT.

ORM-1153: A Novel CD123-Targeting Degrader Antibody Conjugate with Proprietary GSPT1 Degrading Payload for the Treatment of Acute Myeloid Leukemia
Session Category: Experimental and Molecular Therapeutics
Session Title: Antibody-Drug Conjugates and Linker Engineering 2
Location: Poster Section 13
Poster Board Number: 7
Poster Number: 1710

ORM-1153: A Next-Generation CD123-Targeting Degrader Antibody Conjugate (DAC)
Session Category: Experimental and Molecular Therapeutics
Session Title: Quantitative Pharmacology and Translational Modeling
Location: Poster Section 17
Poster Board Number: 12
Poster Number: 1824
Posters will be available on Orum’s website following the presentation.

About ORM-1153

ORM-1153 is a CD123-targeting degrader antibody conjugate developed using Orum’s Dual-Precision TPD² approach. The molecule conjugates a proprietary GSPT1-degrading payload to an anti-CD123 antibody with high internalization efficiency via a β-glucuronide cleavable linker. By combining tumor-selective antibody delivery with targeted protein degradation, ORM-1153 is designed to induce cancer cell death through degradation of GSPT1, a protein implicated in cell survival, including in TP53-mutant AML, while minimizing effects on normal tissues.

About Orum’s TPD² Approach

Orum’s unique Dual-Precision Targeted Protein Degradation (TPD²) approach builds novel targeted protein degraders combined with the precise cell delivery mechanisms of antibodies to generate innovative, first-in-class, cell-selective TPDs for the treatment of cancer and other serious diseases. Orum has developed new targeted protein degrader payloads to specifically degrade an intracellular target protein within cancer cells via the E3 ubiquitin ligase pathway. Conjugated to antibodies, the payloads are designed to be delivered specifically to target cells and precisely degrade the intracellular target protein of interest.

About Orum Therapeutics

Orum Therapeutics is a public biotech pioneering the development of cell-specific, targeted protein degraders (TPD²) with the precision of antibody targeting to develop the next generation of degrader antibody conjugates (DACs) for oncology and beyond. The company is advancing its GSPT1-directed TPD² programs and developing novel degrader payloads to expand the potential of targeted protein degradation. Orum's novel targeted protein degrader payloads are designed to selectively degrade key intracellular proteins, offering a highly targeted approach to treating difficult-to-treat diseases. Orum is located in Lexington, MA, US, and Daejeon, South Korea. For more info, visit www.orumrx.com.

Orum Therapeutics Forward-Looking Statements

This press release contains forward-looking statements that are based on the current expectations and beliefs of Orum Therapeutics, Inc. (“Orum”). Statements in this release regarding matters that are not historical facts, including, but not limited to, statements relating to the advancement of the ORM-1153 program to the clinical stage, the successful translation of preclinical findings to clinical results, the potential indications for ORM-1153, the expansion of the therapeutic window, and the potential success of the TPD² approach, are forward-looking statements. These forward-looking statements are based on management’s expectations and assumptions as of the date of this release and are subject to numerous risks and uncertainties, which could cause actual results to differ materially from those expressed or implied by such statements. These risks and uncertainties include, without limitation, the uncertainty of success in research and development activities; competition from alternative therapies; and risks related to the recruitment and retention of key employees, fluctuating markets and economic conditions, and future fundraising. The forward-looking statements in this presentation speak only as of the date of this release, and Orum undertakes no obligation to update or revise any of the statements. Orum cautions investors not to place considerable reliance on the forward-looking statements contained in this release.

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“The data being presented at AACR reflect continued progress for ORM-1153 and Orum’s Dual-Precision TPD²® approach,” said Sung Joo (SJ) Lee, Ph.D., Founder and CEO of Orum.