Aktis Oncology Announces Presentation of First Clinical Imaging and Dosimetry Data for AKY-2519 at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting

• AKY-2519, a miniprotein radioconjugate targeting B7-H3, to be featured in two poster presentations

• Data facilitate initial understanding of AKY-2519 biodistribution and predicted absorbed doses in tumors and normal tissues in patients with B7-H3 expressing solid tumors

• Phase 1b clinical trial of AKY-2519 to start mid-2026

BOSTON, April 21, 2026 (GLOBE NEWSWIRE) -- Aktis Oncology, Inc. (NASDAQ:AKTS) (the “Company”), a clinical-stage oncology company focused on expanding the breakthrough potential of targeted radiopharmaceuticals to large populations, including those not addressed by existing platform technologies, today announced that clinical imaging and dosimetry data of AKY-2519 in patients with various B7-H3 expressing solid tumors will be presented in two poster presentations at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, being held May 29 – June 2, 2026, in Chicago.

AKY-2519 is a miniprotein radioconjugate targeting B7-H3, which is expressed in several solid tumors, including prostate and lung cancers. In March 2026, the U.S. Food and Drug Administration (FDA) cleared Investigational New Drug (IND) applications for Aktis to proceed to a Phase 1b clinical trial with AKY-25191. AKY-2519 is the second clinical-stage miniprotein radioconjugate discovered using Aktis’ proprietary platform. The Company’s lead miniprotein radioconjugate, AKY-1189, targeting Nectin-4, is currently enrolling patients in a Phase 1b clinical trial. Aktis’ miniprotein radioconjugates are designed to selectively deliver actinium-225 (225Ac), a highly potent alpha-emitting radioisotope, to target-expressing tumors.

Details of the ASCO presentations on AKY-2519 are as follows:

Presentation Title:AKY-2519, a novel B7-H3–targeted radioconjugate, and its biodistribution profile in patients with mCRPCDate and Time:May 30, 1:30 p.m.- 4:30 p.m. CDTPoster Session:Developmental Therapeutics—Molecularly Targeted Agents and Tumor BiologyPoster #:234Abstract #:3097This normal tissue biodistribution and tumor uptake assessment through PET/CT imaging and normal tissues and tumor dosimetry analyses through sequential SPECT/CT imaging of patients with mCRPC was conducted at the Nuclear Medicine Research Infrastructure (NuMeRI), University of Pretoria and Steve Biko Academic Hospital, South Africa.

Presentation Title:First-in-human PET/CT imaging with 68Ga-AKY-2519, a B7-H3 targeted miniprotein radioconjugate, to demonstrate tumor uptake and normal tissue exposure across various advanced solid tumorsDate and Time:May 30, 1:30 p.m.- 4:30 p.m. CDTPoster Session:Developmental Therapeutics—Molecularly Targeted Agents and Tumor BiologyPoster #:235Abstract #:3098This normal tissue biodistribution and tumor uptake assessment through PET/CT imaging in various solid tumors was conducted at the Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium (DKTK), Universitätsklinikum Essen (University Hospital Essen), Essen, Germany.

About Aktis’ miniprotein radioconjugate platformAktis has developed a proprietary, isotope-agnostic miniprotein radioconjugate platform to selectively deliver the tumor-killing properties of radioisotopes to targeted tumors. Aktis’ therapeutic miniprotein radioconjugates are designed to maximize anti-cancer activity through high tumor penetration coupled with internalization and retention in cancer cells, while rapidly clearing from normal organs and tissues. The Aktis platform further enables clinicians to visualize and verify target engagement with imaging isotopes prior to exposure to therapeutic radioisotopes. Leveraging this platform, and its patient-first end-to-end supply chain, Aktis is advancing a pipeline of next-generation targeted radiopharmaceuticals to address the unmet needs of patients across a broad spectrum of solid tumors.

About Aktis OncologyAktis Oncology, Inc. is a clinical-stage oncology company focused on expanding the breakthrough potential of targeted radiopharmaceuticals to large patient populations, including those not addressed by existing platform technologies. Aktis’ most advanced pipeline program, AKY-1189, is a miniprotein radioconjugate targeting Nectin-4, with multi-indication potential across multiple tumor types, including locally advanced or metastatic urothelial cancer, breast cancer, non-small cell lung cancer, colorectal cancer, cervical cancer, and head and neck cancer. Aktis’ second pipeline program, AKY-2519, is a miniprotein radioconjugate targeting B7-H3 expressing tumors, including prostate, lung and other solid tumors. Aktis has a strategic collaboration with Eli Lilly and Company to leverage its miniprotein platform to develop novel radioconjugates outside of Aktis’ proprietary pipeline. For more information, please visitwww.aktisoncology.com.

Forward-looking statementsThis press release contains forward looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, including statements regarding the Company’s expectations about the timing of ongoing and planned clinical trials and regulatory filings, goals to develop and commercialize its product candidates, its liquidity and capital resources, and other statements identified by words such as “could,” “expects,” “intends,” “may,” “plans,” “potential,” “should,” “will,” “would,” or similar expressions and the negatives of those terms. Forward looking statements are not promises or guarantees of future performance, and are subject to a variety of risks and uncertainties, many of which are beyond the Company’s control, and which could cause actual results to differ materially from those contemplated in such forward-looking statements. These factors include risks related to the timing of enrollment, commencement and completion of the Company’s ongoing and planned clinical trials, the Company’s limited operating history, its ability to obtain necessary funding, its ability to generate positive clinical trial results for its product candidates and other risks inherent in clinical development, the timing and scope of regulatory approvals, changes in laws and regulations to which the Company is subject, competitive pressures, risks relating to business interruptions, and other risks set forth under the heading “Risk Factors” of the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 and in subsequent filings with the Securities and Exchange Commission. The Company’s actual results could differ materially from the results described in or implied by such forward looking statements. Forward-looking statements speak only as of the date hereof, and, except as required by law, the Company undertakes no obligation to update or revise these forward-looking statements.

1IND applications were cleared for [64Cu]Cu-AKY-2519 for imaging and [225Ac]Ac-AKY-2519 for therapeutic use.