On April 17, 2026 Orum Therapeutics ("Orum" or the "Company") (KRX: 475830), a biotechnology company pioneering the field of degrader-antibody conjugates (DACs), reported the presentation of new preclinical data for ORM-1153, a CD123-targeting DAC designed to selectively deliver a proprietary GSPT1-degrading payload, in development for the treatment of AML and other CD123-positive hematological malignancies. The data were presented in two posters at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2026.

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"These data show strong preclinical activity and the potential for a differentiated safety and tolerability profile, supporting the advancement of ORM-1153 as a next-generation CD123-targeting degrader-antibody conjugate for acute myeloid leukemia," said Chad May, Ph.D., Chief Scientific Officer of Orum. "Our approach combines a proprietary CD123-antibody and novel GSPT1-targeted protein degrader with the goal of achieving greater selectivity than conventional cytotoxic antibody-drug conjugates. We believe this strategy can enable more effective and better-tolerated therapies for patients with AML."

The first poster (Abstract Number: 1824) highlights how ORM-1153 was engineered with a proprietary CD123-antibody designed for enhanced internalization and reduced Fc-gamma receptor interactions, together with a linker optimized for plasma stability, an approach intended to improve delivery, reduce off-target and immune cell engagement, and support favorable pharmacologic properties. Consistent with that design, ORM-1153 showed strong preclinical anti-leukemia activity at low doses, along with prolonged accumulation in tumors, undetectable systemic free payload, and favorable repeat-dose non-human primate findings supporting a manageable safety and tolerability profile.

Data from the second poster (Abstract Number: 1710) extend Orum’s previously presented findings by showing activity across primary AML patient samples and in models with relevant tumor mutations, including TP53. Taken together, the findings support the potential for broad activity in AML, including in patients with TP53 mutations.

"These AACR (Free AACR Whitepaper) data are particularly encouraging in the context of AML, where many patients, especially those with TP53 mutations, continue to have limited treatment options and poor outcomes," said Olaf Christensen, M.D., Chief Medical Officer of Orum. "The activity we are seeing across primary patient samples and TP53-relevant models, together with a consistent pharmacologic and tolerability profile, supports the continued advancement of ORM-1153 toward clinical development."

Both posters are available on Orum’s website and will be presented at AACR (Free AACR Whitepaper) on Monday, April 20, from 9 am to 12 pm PDT.

About ORM-1153

ORM-1153 is a CD123-targeting degrader-antibody conjugate developed using Orum’s Dual-Precision TPD² approach. The molecule is built from two proprietary elements, a GSPT1-degrading payload and an anti-CD123 antibody engineered for high internalization efficiency, conjugated with a cleavable β-glucuronide 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.

(Press release, Orum Therapeutics, APR 17, 2026, View Source [SID1234664496])