Press release

Preclinical data on novel NK-Cell engager to be presented at the AACR Annual Meeting 2026

Stockholm – April 13, 2026 – Oncopeptides AB (publ) (Nasdaq Stockholm: ONCO), a biotech company focused on difficult-to-treat cancers, today announces that new preclinical data for its proprietary SPiKE platform has been accepted for presentation at the American Association for Cancer Research (AACR) Annual Meeting 2026. The study, which evaluates a novel NK-cell engager in combination with a NK cell product in multiple myeloma, will be presented as a poster during the congress which is held in San Diego, California between April 17-22, 2026.

The presentation, titled “Preclinical efficacy of a bispecific NK cell engager studied using a humanized multiple myeloma mouse model,” details the synergistic effects of combining Oncopeptides’ affibody-derived bispecific engager with expanded adaptive NK cells (ADAPT-NK). The study demonstrates significant inhibition of tumor growth in bone marrow and other organs in a newly developed humanized mouse model.

“Sharing these results at AACR allows us to showcase the innovative potential of our SPiKE platform to the global cancer research community,” says Stefan Norin, Chief Medical Officer at Oncopeptides. “The data provides strong preclinical proof-of-concept for our ability to redirect the innate immune system. By targeting BCMA with high precision, we aim to develop a new class of immunotherapies that can overcome the limitations and toxicities associated with current T-cell-directed treatments.”
The research is a result of a collaborative effort within the Eurostars-funded NK ENGAGE project, involving leading academic institutions, Pharmatest Services and Oncopeptides.

“We are very pleased to see our research recognized by the AACR,” says Mari I. Suominen, Research Director at Pharmatest Services. “The developed model replicates several aspects of the disease whereof lesions due to bone resorption is one of them. The efficient tumor cell lysis observed in these models reinforce our belief that NK-cell engagers could become a vital component in the future treatment landscape for relapsed or refractory multiple myeloma. We look forward to discussing these findings with our peers in San Diego.”

Poster Presentation Details:

Abstract Title: Preclinical efficacy of a bispecific NK cell engager studied using a humanized multiple myeloma mouse model
Conference: AACR Annual Meeting 2026, San Diego, CA
Session: PO.IM02.02 - Innate Immunity in Cancer
Session time: 09.00am-12.00pm, April 20, 2026
Abstract Number: 1598 / 19

About Oncopeptides
Oncopeptides is a Swedish biotech company focusing on research, development and commercialization of targeted therapies for difficult-to-treat cancers.

The company uses its proprietary Peptide Drug Conjugate platform (PDC) to develop compounds that rapidly and selectively deliver cytotoxic agents into cancer cells. Its flagship drug is currently being commercialized in Europe with partnership agreements for South Korea, the Middle East and Africa and elsewhere.

Oncopeptides is also developing several new compounds based on its two proprietary technology platforms PDC and SPiKE.

The company was founded in 2000, has about 80 employees with operations in Sweden, Germany, Austria, Spain and Italy. Oncopeptides is listed on Nasdaq Stockholm with the ticker ONCO.

For more information see: www.oncopeptides.com