Zelluna receives Independent Data Monitoring Committee recommendation to continue patient enrolment in ZIMA-101

• Independent Data Monitoring Committee (IDMC) recommends recruitment of the next two patients at the first dose level
• First patient completed the planned first treatment cycle with no serious adverse events or dose-limiting toxicities observed
• Study progressing as planned following favourable initial safety review

17 August 2026 – Zelluna ASA (OSE: ZLNA) today announced that the Independent Data Monitoring Committee (IDMC) has completed its review of the first patient’s safety data from the first-in-human ZIMA-101 study and has recommended that the study continues as planned.

The first patient, treated at the lead clinical site, The Christie NHS Foundation Trust received all three planned doses of the drug candidate ZI-MA4-1 on Days 1, 4 and 8 of the treatment cycle, followed by a protocol defined safety observation period. An independent group of medical and scientific experts – the IDMC – has now reviewed these data. Following its review, the IDMC identified no dose-limiting toxicities or other safety concerns that would preclude continuation of the study at the current dose level. The committee therefore recommended that the study proceed with enrolment of two additional patients at the same dose level.

ZIMA-101 follows a stepwise approach commonly used in early-stage clinical trials, where safety is carefully assessed before additional patients are treated. Following the IDMC's recommendation, the study can now proceed with enrolment of two additional patients at the first dose level. Patient screening and recruitment are ongoing at both clinical sites in the United Kingdom – The Christie and The Royal Marsden NHS Foundation Trust.

These initial safety observations represent the first clinical data from the ZIMA-101 study, consistent with the Company's previously communicated guidance that initial clinical data would begin to emerge from mid-2026. The Company expects further data to emerge as additional patients are enrolled and followed over time.

"These encouraging initial safety observations represent an important first step in the clinical evaluation of ZI-MA4-1 and our TCR-NK platform” said Namir Hassan, Chief Executive Officer of Zelluna. “The first patient received all three planned doses, and the independent committee's recommendation enables us to continue recruitment at the first dose level. We are pleased with the progress to date, while remaining mindful that the study is still at an early stage. We stay firmly focused on patient safety, disciplined clinical execution and the careful generation of further data."

Professor Fiona Thistlethwaite, Consultant Medical Oncologist at The Christie and honorary professor at The University of Manchester said “Following the IDMC review meeting we are very pleased to have permission to continue recruitment and offer the opportunity to patients to participate in this exciting study”.

About ZIMA-101

ZIMA-101 is a Phase 1 clinical trial evaluating the safety, tolerability and preliminary anti-tumour activity of ZI-MA4-1 in patients with advanced solid tumours that express the protein MAGE-A4. The study is being conducted at The Christie and The Royal Marsden NHS Foundation Trusts in the United Kingdom. The study design involves treating three patients at each dose level, with an independent committee reviewing safety data from the first patient before recommending enrolment of the remaining two patients at that dose level.

About ZI-MA4-1

ZI-MA4-1 is Zelluna's lead allogeneic TCR-NK product candidate and the world's first MAGE-A4-targeting TCR-NK cell- therapy in clinical development. The product combines the natural tumour-killing ability of NK cells with precision targeting of MAGE-A4 – a protein found on the surface of several common cancer types, including ovarian cancer, lung cancer, synovial sarcoma and head and neck cancer. The therapy is manufactured as an "off-the-shelf" product that can be administered directly to patients without individual customisation, making it more accessible than traditional cell therapies.

For further information, please visit www.zelluna.com or contact:

Namir Hassan, CEO

Email: namir.hassan@zelluna.com

Phone: +44 7720 687608

Geir Christian Melen, CFO

Email: geir.christian.melen@zelluna.com

Phone: +47 913 02 965

About Zelluna ASA

Zelluna ASA (OSE: ZLNA) is a clinical-stage company pioneering allogeneic 'off-the-shelf' T Cell Receptor -based Natural Killer (TCR-NK) cell therapies for the treatment of solid cancers. The Company's technology combines the natural tumour-killing ability of NK cells with precision targeting of solid tumours enabled by affinity-engineered T cell receptors (TCRs). The goal is to create effective, scalable and accessible treatments for patients with solid tumours – a patient population with significant unmet medical need. Zelluna is listed on the Oslo Stock Exchange under the ticker ZLNA and is headquartered at the Oslo Cancer Cluster Innovation Park in Oslo, Norway.

This information is considered to be inside information pursuant to the EU Market Abuse Regulation and is subject to the disclosure requirements pursuant to Section 5-12 of the Norwegian Securities Trading Act. This stock exchange announcement was published by Geir Christian Melen, CFO of Zelluna ASA, on 17 August 2026 at 13:30