Aktis Oncology Initiates Second Phase 1b Clinical Trial for AKY-2519, a Miniprotein Radioconjugate Targeting B7-H3

Two AKY-2519 trials are now underway, alongside an enrolling AKY-1189 trial with preliminary data expected in the first quarter of 2027.

Rhea-AI Summary

Aktis Oncology (AKTS) initiated its second Phase 1b trial of AKY-2519, evaluating the B7-H3-targeting radioconjugate in lung cancer and other solid tumors.

The BActinium-2 study will enroll patients with non-small cell lung cancer and other B7-H3-expressing tumors across multiple centers. It is open-label, meaning treatment assignments are known, and will explore three dose levels. The protocol permits enrollment expansion at selected doses while dose escalation continues. Enrollment remains ongoing in BActinium-1, initiated in May 2026 for metastatic castration-resistant prostate cancer, with preliminary data expected in 2027. Aktis described earlier human imaging and radiation-dose data as showing tumor uptake and retention with limited normal tissue exposure. Its separate Phase 1b NECTINIUM-2 trial of AKY-1189, targeting Nectin-4-expressing tumors, is also enrolling, with preliminary data expected in the first quarter of 2027.

5 points · 0 major

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Hollow bars mark forward-looking points. How the balance works

Positive

• Moderate pointBActinium-2 initiated, extending AKY-2519 clinical evaluation to non-small cell lung cancer and other B7-H3-expressing solid tumors.
• Minor point. Forward-looking: it has not happened yet and may not happen.Three dose levels planned in BActinium-2, with optional enrollment expansion at selected doses during escalation.
• Minor point. Forward-looking: it has not happened yet and may not happen.BActinium-1 enrollment ongoing in metastatic castration-resistant prostate cancer; preliminary AKY-2519 data expected in 2027.
• Minor pointEarlier human imaging and radiation-dose data showed tumor uptake and retention with limited normal tissue exposure.
• Minor point. Forward-looking: it has not happened yet and may not happen.NECTINIUM-2 enrollment ongoing for AKY-1189; preliminary data expected in the first quarter of 2027.

Negative

• None.

Key Figures

Dose levels: 3 dose levels Preliminary data timing: 2027

Dose levels

3 dose levels

BActinium-2 trial

Preliminary data timing

2027

BActinium-1 mCRPC trial

Previous Clinical trial Reports

1 past event · Latest: May 04

Same Type 1 event

1. May 04

   Phase 1b trial initiation

   24h Move

   +2.3%

   Initiated AKY-2519's first Phase 1b mCRPC trial; planned a B7-H3 basket trial for H2 2026.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

nsclc, mcrpc, dosimetry, open-label, +1 more

5 terms

nsclc medical

"patients with non-small cell lung cancer (NSCLC)"

NSCLC stands for non-small cell lung cancer, which is the most common type of lung cancer. It develops in the lungs and can spread to other parts of the body, making it serious but often treatable if caught early. Understanding NSCLC helps people recognize the importance of lung health and early detection.

mcrpc medical

"metastatic castration-resistant prostate cancer (mCRPC)"

mCRPC stands for metastatic castration‑resistant prostate cancer, a form of prostate cancer that has spread beyond the prostate and keeps progressing despite treatments that lower male hormones. It matters to investors because this stage is harder to treat, drives demand for new therapies, and often involves large, expensive clinical trials and regulatory decisions that can strongly influence a drug maker’s future revenue and stock value—think of it as a stubborn problem that creates both medical need and commercial opportunity.

dosimetry medical

"first-in-human clinical imaging and dosimetry data"

Dosimetry is the measurement and calculation of how much ionizing radiation is absorbed by people, tissues, or devices, similar to a thermostat tracking temperature in different rooms to know where and how much heat is present. Investors should care because accurate dosimetry underpins safety, treatment effectiveness, regulatory approval, and liability for products and services that use radiation—affecting market access, costs, and commercial risk.

open-label medical

"Phase 1b, multicenter, open-label BActinium-2 trial"

Open-label describes a situation where everyone involved in a study or process knows the full details, such as who is receiving a treatment or intervention. For investors, understanding whether a project or product is open-label helps gauge the level of transparency and potential biases, influencing trust and decision-making. It’s like knowing whether a test or experiment is conducted openly or behind closed doors.

radioconjugate medical

"a miniprotein radioconjugate targeting B7-H3"

A radioconjugate is a medicine made by attaching a small amount of radioactive material to a targeting molecule so the radiation is delivered directly to specific cells, like a guided missile carrying a tiny explosive to a precise address. Investors care because its safety, effectiveness, manufacturing complexity, and regulatory path determine development costs, market size and reimbursement potential, affecting a company’s future revenue and risk profile.

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• Phase 1b BActinium-2 clinical trial is evaluating AKY-2519 in patients with non-small cell lung cancer (NSCLC) and other B7-H3 expressing tumors
• Enrollment is ongoing in the Phase 1b BActinium-1 clinical trial of AKY-2519 in metastatic castration-resistant prostate cancer (mCRPC); preliminary data expected in 2027

BOSTON, Oct. 01, 2026 (GLOBE NEWSWIRE) -- Aktis Oncology, Inc. (NASDAQ:AKTS) (“Aktis” or the “Company”), a clinical-stage oncology company focused on expanding the breakthrough potential of targeted radiopharmaceuticals to large populations, today announced the initiation of the Phase 1b BActinium-2 trial of AKY-2519¹ in patients with NSCLC and other B7-H3 expressing solid tumor types. The BActinium-2 trial is part of Aktis’ clinical development strategy to develop AKY-2519 broadly in several B7-H3 expressing tumors. In May 2026, Aktis initiated the Phase 1b BActinium-1 trial of AKY-2519 in mCRPC patients, with preliminary data expected in 2027.

“AKY-2519 has the potential to be a differentiated therapeutic option for patients with B7-H3 expressing solid tumors, as demonstrated by the first-in-human clinical imaging and dosimetry data presented at ASCO earlier this year,” said Akos Czibere, MD, PhD, Chief Medical Officer at Aktis. “With both Phase 1b trials of AKY-2519 now underway, we are efficiently generating indication-relevant data in several cancers with large patient populations to evaluate where AKY-2519 can be most effective.”

The first-in-human clinical imaging and dosimetry data for AKY-2519 across mCRPC, NSCLC and other B7-H3 expressing tumor types presented at the American Society of Clinical Oncology (ASCO) Annual Meeting in May 2026 demonstrated robust tumor uptake and retention of AKY-2519 with limited normal tissue exposure, suggesting the potential for a wide therapeutic window and differentiated profile compared to approved radiopharmaceuticals.

The Phase 1b, multicenter, open-label BActinium-2 trial will enroll patients with NSCLC and other B7-H3 expressing solid tumors. The study will explore three dose levels. Per protocol, Aktis has the ability to expand enrollment at selected dose levels to generate additional clinical data while dose escalation continues.

In addition to the AKY-2519 BActinium-1 and BActinium-2 trials, Aktis is also currently enrolling patients in an ongoing Phase 1b NECTINIUM-2 trial of its most advanced program, AKY-1189, a miniprotein radioconjugate targeting Nectin-4 expressing tumors, with preliminary data expected in the first quarter of 2027.

About Aktis’ miniprotein radioconjugate platform

Aktis 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 anticancer 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 clinical supply chain built for resiliency and scalability, 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 Oncology

Aktis 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 clinical-stage 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, and other solid tumor cancers. Aktis’ second clinical-stage pipeline program, AKY-2519, is a miniprotein radioconjugate targeting B7-H3 expressing tumors, including prostate, lung, and other solid tumors. Aktis has a discovery collaboration with Eli Lilly and Company to leverage Aktis’ miniprotein platform to develop novel radioconjugates outside of its proprietary pipeline. For more information, please visit www.aktisoncology.com.

Forward-looking statements

This 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 and results of ongoing and planned clinical trials and regulatory filings, goals to develop and commercialize its product candidates, 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 commencement and completion of the Company’s ongoing and planned clinical trials, the Company’s limited operating history, 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 30, 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.

Media contact:
Melone Communications, LLC
Liz Melone
617-256-6622
liz@melonecomm.com

Investor contact:
Precision AQ
Alex Lobo
212-698-8802
Alex.lobo@precisionaq.com

¹AKY-2519 refers to the therapeutic radioconjugate [²²⁵Ac]Ac-AKY-2519.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What is Aktis Oncology testing in the AKY-2519 BActinium-2 trial?

The Phase 1b BActinium-2 trial is evaluating AKY-2519 in patients with non-small cell lung cancer and other B7-H3-expressing solid tumors. The multicenter, open-label study will explore three dose levels and permits expanded enrollment at selected doses while dose escalation continues.

When does Aktis Oncology expect preliminary data from its ongoing trials?

Preliminary data from AKY-2519 BActinium-1 are expected in 2027, while preliminary data from AKY-1189 NECTINIUM-2 are expected in the first quarter of 2027. BActinium-1 is enrolling patients with metastatic castration-resistant prostate cancer; NECTINIUM-2 evaluates AKY-1189 targeting Nectin-4-expressing tumors.