Phase I/II NECVAX-NEO1 trial in patients with triple-negative breast cancer confirm its potential safety and immunogenicity and provide clinical proof-of-concept for the use of this investigational oral bacteria-based DNA neoantigen therapy in high-risk early-stage cancer patients including the perioperative setting as well.

Tokyo, Japan — October 22, 2026, 04:00 PM JST — NEC Bio will be presenting results from the Phase I/II TNBC clinical trial of its orally administered individualized neoantigen therapy, NECVAX-NEO1, used in combination with checkpoint inhibitors (CPIs) and chemotherapy for patients with triple-negative breast cancer (TNBC). The findings are being presented in an e-poster at the ESMO Congress in Madrid, Spain, from October 23 to 27, 2026.

NECVAX-NEO1 is an AI powered individualized bacteria-based oral DNA therapy that combines IMMUNASIGHT®, NEC Bio’s proprietary AI based neoantigen prediction platform for identifying the most immunogenic patient-specific neoepitopes, with TORAPRIME®, its proprietary oral bacterial neoantigen delivery platform. This therapy is designed to activate a patient’s immune system, prompting a T-cell response that can precisely target and eliminate tumor cells based on an individual’s unique neoantigens.

In the first cohort of the phase I/II study, 8 patients with TNBC were treated with NECVAX-NEO1 in a neoadjuvant setting. All patients were treated with 2 courses of neoadjuvant chemotherapy and pembrolizumab before the planned surgery. After 12 weeks of chemotherapy/pembrolizumab, NECVAX-NEO1 was added on top, with an optional adjuvant treatment phase after surgery. NECVAX-NEO1 on top of chemotherapy/immunotherapy was generally well tolerated. Five patients achieved pathological complete response at surgery, accompanied by corresponding biomarker changes. In all patients, immunogenic neoepitopes used in NECVAX-NEO1 were detected, as demonstrated by ELISPOT analysis.

Regarding the results of the clinical study, Dr. Heinz Lubenau, CEO of NEC Bio Therapeutics, commented, "Our clinical Phase I/II data are demonstrating promising immune responses in the neoadjuvant treatment of early-stage TNBC patients. The results are encouraging, so we are extending the trial to n=28 patients, including patients in the U.S., as we recently received IND approval to conduct a clinical trial in the country. The additional patients in cohort 2 are being treated with a higher dose of NECVAX-NEO1 on top of Keynote-522 standard of care regimen, which includes pembrolizumab. We look forward to further evaluation of NECVAX-NEO1 as a potential treatment option for cancer patients with high medical need."

Akira Kitamura, CEO, NEC Bio, further commented, "The results presented at ESMO 2026 are an important accomplishment that further strengthens NEC Bio’s confidence in the potential of NECVAX-NEO1 as an individualized neoantigen therapy. By combining our proprietary AI-powered neoantigen discovery platform, IMMUNASIGHT® with a differentiated neoantigen delivery platform TORAPRIME®, we aim to deliver highly individualized treatment approaches for patients with cancer. These findings support our continued commitment to advancing innovative therapies that have the potential to improve patient outcomes and expand the possibilities of precision treatment in oncology."

Details of the poster are below:

Poster title: Phase I/II study of neoadjuvant personalized vaccination with NECVAX-NEO1, in combination with pembrolizumab and chemotherapy in early-stage triple-negative breast cancer, evaluating safety, immunogenicity, and preliminary clinical activity NCT06631092

Authors: Peter A. Fasching, Katharina Keller, Oliver Schleicher, Carlo Fremd, Laura Michel, Michael Platten, Isabel Poschke, Ingrid Hülsmeyer, Margarida Garcia, Alvaro Aranguren, Kaidre Bendjama, Daiki Mori, Heinz Lubenau, Andreas Schneeweiss

Poster Number: 4694eP

Date: 23 October 2026

The poster may also be found here: https://www.nec-bio.com/en_DD/img/20261022_ESMO2026_NECVAX-NEO1_05_DE_poster.pdf
Trial details can also be viewed at: NCT06631092

NECVAX-NEO1 is currently under evaluation at additional clinical trial sites in several European countries.

About IMMUNASIGHT®
IMMUNASIGHT® is NEC Bio's AI-powered neoantigen discovery platform designed to identify and prioritize clinically relevant immune targets for next-generation immunotherapies. By modeling the complete antigen presentation pathway, from mutation identification and processing to presentation, together with immunogenicity, IMMUNASIGHT® helps researchers narrow thousands of potential targets to those most likely to elicit meaningful anti-tumor immune responses. The cloud-native platform supports scalable, reproducible, and rapid analysis for oncology research and therapeutic development. IMMUNASIGHT® is registered in certain jurisdictions

About TORAPRIME®
TORAPRIME® is NEC Bio's proprietary oral bacteria-based delivery platform that uses attenuated bacteria to deliver DNA encoding selected neoantigens through the gut immune system. Following oral administration, the platform is designed to induce neoantigen-specific T cell responses and support systemic anti-tumor immune responses. TORAPRIME® is the delivery technology underlying NECVAX-NEO1. TORAPRIME® is registered in certain jurisdictions.

About NEC Bio
NEC Bio is the biotechnology arm of NEC Corporation, headquartered in the Netherlands, and focused on leveraging state-of-the-art AI technologies to address the world's most pressing healthcare challenges. Leveraging cutting-edge science, data, and innovation, NEC Bio is dedicated to developing personalized therapies designed to transform patient outcomes and improve quality of life globally. With a growing international footprint, NEC Bio includes subsidiaries such as NEC OncoImmunity in Oslo, Norway, and NEC Bio Therapeutics in Mannheim, Germany—each contributing specialized expertise across immunotherapy, precision medicine, and translational research. Together, these entities form a collaborative ecosystem committed to accelerating innovation from discovery to patient impact.
To learn more, visit www.nec-bio.com and follow us on LinkedIn for the latest updates.

About NEC Bio Therapeutics
NEC Bio Therapeutics, established in Mannheim, Germany, focuses on the clinical strategy and development, as well as planning and execution of clinical trials in the oncology area. It is a subsidiary of NEC Bio, the biotech arm of NEC Corporation.

About NEC Corporation
The NEC Group leverages technology to create social value and promote a more sustainable world where everyone has the chance to reach their full potential. NEC Corporation was established in 1899. Today, the NEC Group’s approximately 110,000 employees utilize world-leading AI, security, and communications technologies to solve the most pressing needs of customers and society.

For more information, please visit https://www.nec.com, and follow us on LinkedIn and YouTube.