ExpreS2ion Biotech

Phase I Clinical Trial – ES2B-C001 (HER2-Expressing Cancers)
As previously communicated, ExpreS2ion expected to dose the first patient in its ongoing Phase I clinical trial for the therapeutic HER2 cancer vaccine candidate, ES2B-C001, in the first quarter of 2025. As of today, the first patient has not yet been dosed.

The Company notes that slower-than-expected patient recruitment is not uncommon in early-stage clinical development. Importantly, the delay is not related to any safety or scientific concerns with the vaccine candidate.

The Company continues to work diligently to facilitate enrolment, including exploring potential operational measures to accelerate recruitment. An update will be published immediately upon first patient dosing, in line with prior communication and applicable regulations.

Strategic Review – CMV Vaccine Program
Following an internal strategic review, ExpreS2ion has decided not to pursue further development of its CMV (Cytomegalovirus) vaccine candidate, previously conducted in collaboration with Evaxion Biotech A/S.

This decision reflects ExpreS2ion’s focus on programs with the strongest fit to its proprietary technology platform and core strategic objectives. Ending development of this non-core program will contribute to improved resource allocation and an extended financial runway.

All rights to the CMV vaccine candidate revert to Evaxion following the conclusion of the collaboration.

About ES2B-C001 (HER2-VLP)
ES2B-C001 is an innovative therapeutic vaccine developed specifically for HER2-expressing cancers. This novel approach combines ExpreS2ion's ExpreS2 production platform with AdaptVac's VLP technology, both of which have been proven in clinical Phase III. The HER2-VLP vaccine’s design aims to stimulate a robust and durable polyclonal immune response against HER2-expressing tumours, offering a complementary strategy to current treatments. Preclinical studies, as highlighted by Ruzzi et al. (2022), have demonstrated the vaccine’s safety and efficacy across multiple animal models, significantly inhibiting tumour growth and improving survival rates. By leveraging the patient’s immune system, ES2B-C001 addresses the complexities of HER2-expressing breast cancers, potentially offering enhanced therapeutic options and filling critical gaps in the current treatment landscape.

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