ExpreS2ion: Oxford malaria data add independent clinical validation of the ExpreS2 platform

ExpreS2ion today highlighted new Phase Ia clinical data from the University of Oxford's BIO-002 study, in which the RH5.1 malaria antigen — produced using ExpreS2ion's proprietary Drosophila S2 expression platform — demonstrated a favourable safety profile, consistent antibody responses with functional activity against the malaria parasite, and comparable immunogenicity across two dosing regimens. The study, conducted in healthy UK adults by the Universities of Oxford and Sheffield, provides further independent clinical validation of the ExpreS2 platform in a human setting.

The release comes during the subscription period of ExpreS2ion's rights issue of approximately SEK 53 million (16–30 April, SEK 1.60 per unit), where ~55% of net proceeds are earmarked for completing Phase I of ES2B-C001. While BIO-002 does not directly impact the ES2B-C001 thesis, the additional platform validation is constructive context during the subscription period.

You can read more about rights issue here: 

https://www.inderes.dk/analyst-comments/expres2ion-final-terms-set-on-rights-issue-of-sek-53-million

BIO-002 evaluated the RH5.1 protein formulated with Matrix-M adjuvant using a standard-dose and a higher-dose regimen. The key finding is that the standard-dose regimen achieved similar immune responses to the higher-dose approach, with no serious adverse events reported. Beyond immunogenicity, the dose-sparing observation has practical implications for manufacturing efficiency and scalability, a critical consideration for any vaccine intended for global deployment. Oxford currently runs ten clinical trials across various malaria vaccines produced on the ExpreS2 platform, and BIO-002 adds to a growing body of clinical evidence supporting its use in human vaccine development.

The RH5.1 antigen is part of the licensing agreement with Serum Institute of India (SII) executed in November 2025, covering both RH5.1 and R78C. Under the agreement, ExpreS2ion is entitled to upfront and milestone payments in the low single-digit EUR millions and royalties ranging from below 1% to mid-single digit percentages on future net sales. Today's dose-sparing finding is particularly relevant in this context, if confirmed in later-stage studies, it could reduce cost of goods per dose, a central consideration for vaccines targeting low- and middle-income markets where SII's manufacturing and distribution network across more than 170 countries is a decisive advantage.

The study also illustrates ExpreS2ion's partnered development model, in which ExpreS2-enabled assets are advanced through external partnerships while the company retains focus on its lead programme, ES2B-C001.

While BIO-002 is a malaria study, the data provide additional independent validation of the same ExpreS2 expression system used to produce the HER2 antigen in ES2B-C001. The platform has now generated clinical data across the Phase III ABNCoV2 COVID-19 programme, the ongoing Phase I ES2B-C001 breast cancer study, and now BIO-002 — demonstrating consistent manufacturability and immunogenicity across diverse targets. For investors evaluating ES2B-C001, this cross-programme evidence reduces one layer of technical risk in the lead oncology asset.

In our published investment case, we value ExpreS2ion's platform, CRO business, and 34% stake in AdaptVac at a combined SEK 141 million alongside the risk-adjusted ES2B-C001 DCF — reflecting our view that the platform carries meaningful value beyond the lead oncology candidate. The malaria programme is modelled conservatively as a mid single-digit SEK million peak annual revenue contributor, which remains modest relative to the ES2B-C001 opportunity but is not insignificant against the current market capitalisation of approximately SEK 55 million. Today's data incrementally strengthen the case for this platform value by adding another layer of independent human clinical validation. Taken together with the recent ES2B-C001 update — eight of nine patients responding, DSMB endorsement to escalate to 450 µg — BIO-002 reinforces the picture of a platform generating consistent clinical evidence across multiple therapeutic areas in a defining year for ExpreS2ion.

Disclaimer: HC Andersen Capital receives payment from ExpreS2ion Biotechnologies for a Digital IR/Corporate Visibility subscription agreement. /Michael Friis, 12:01, 22/04-2026