ExpreS2ion Biotech : Interim report for January – March 2024 (Q1)

ExpreS2ion Biotechnologies

• innovative vaccines for a healthier world

2024 first quarter interim report

Forward-looking statements and disclaimer

This report contains forward-looking statements. The words "believe", "expect", "anticipate", "intend" and "plan" and similar expressions identify forward-looking statements. All statements other than statements of historical facts included in this report, including, without limitation, those regarding our financial position, business strategy, plans and objectives of management for future operations (including development plans and objectives relating to our products), are forward-looking statements. Such forward- looking statements involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by such forward- looking statements. Such forward-looking statements are based on numerous assumptions regarding our present and future business strategies and the environment in which we will operate in the future. The important factors that could cause our actual results, performance or achievements to differ materially from those in the forward- looking statements include, among others, risks associated with product discovery and development, uncertainties related to the outcome of clinical trials, slower than expected rates of patient recruitment, unforeseen safety issues resulting from the administration of our products in patients,

EXPRES2ION 2024 FIRST QUARTER INTERIM REPORT

uncertainties related to product manufacturing, the lack of market acceptance of our products, our inability to manage growth, the competitive environment in relation to our business area and markets, our inability to attract and retain suitably qualified personnel, the unenforceability or lack of protection of our patents and proprietary rights, our relationships with affiliated entities, changes and developments in technology which may render our products obsolete, and other factors. Further, certain forward- looking statements are based upon assumptions of future events which may not prove to be accurate. The forward- looking statements in this document speak only as at the date of this report. ExpreS2ion Biotech does not undertake any obligation to update or revise forward- looking statements in this report nor to confirm such statements to reflect subsequent events or circumstances after the date made or in relation to actual results, unless required by law.

Definitions

"ExpreS2ion Biotech Holding AB" refers to ExpreS2ion Biotech Holding AB with

corporate identity number 559033-3729. "The Company" or "ExpreS2ion" refers to the group, i.e. ExpreS2ion Biotech Holding AB and its fully owned operational subsidiary ExpreS2ion Biotechnologies ApS, Denmark.

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EXPRES2ION 2024 FIRST QUARTER INTERIM REPORT

To our shareholders:

"We are starting 2024 invigorated by our new strategy with clear objectives, the strong progress of our proprietary pipeline, and a broadly validated platform. The overall conditions for early - stage biotech funding remain challenging and selective. Against this backdrop, we have established our priorities with a focus on advancing the lead proprietary asset, the ES2B -C001

breast cancer program, towards a clinical trial application."

We are starting 2024 invigorated by our new strategy with clear objectives, the strong progress of our proprietary pipeline, and a broadly validated platform

Bent U. Frandsen

CEO, ExpreS2ion Biotech Holding AB

Advancing our proprietary pipeline

Shortly after ending the reporting period, we announced the completion of the important GLP safety study for ES2B- C001. This is the result of comprehensive preparation and marked an important step towards submitting a clinical trial application later in 2024 with the aim of initiating a first-in-human Phase I trial within the next year, subject to funding. We are currently manufacturing the final drug substance, which is the active pharmaceutical ingredient. The remaining steps in manufacturing (CMC) include assembly into the final drug product with all appropriate packaging, labeling, as well as quality control and stability tests.

The process for the selection of a CRO partner is well underway, and we are also preparing the regulatory process for submitting the CTA. We have engaged

advisors to actively promote the ES2B- C001 project to potential partners as a way of securing funding for initiating first-in-human studies.

Our partnership with Evaxion on a cytomegalovirus vaccine (CMV) utilizing a proprietary AI-driven technology platform is also progressing according to plan as we continue the process for accelerated selection of CMV antigens.

Collaborative projects

Our ExpreS2 platform is also used in our partner development programs, including in the VICI disease consortium aimed at developing a vaccine against the Nipah virus, and in the malaria vaccine projects conducted by Oxford University, who have initiated an additional two clinical studies for malaria and now have seven clinical trials for malaria underway.

Corporate matters

In February, we announced that the completion of Bavarian Nordic's clinical Phase III study for the COVID-19 vaccine ABNCoV2 had triggered a milestone payment to AdaptVac, in which ExpreS2ion holds a 34% ownership. Towards the end of April, we announced that ExpreS2ion would receive approximately SEK 22.5 million in dividends through our stake in AdaptVac.

With a cash position of SEK 60.2 million at the end of the first quarter and the dividends from AdaptVac, ExpreS2ion is funded into 2025, including the submission of the clinical trial application for the ES2B-C001 breast cancer program. Additional proceeds from the rights issue announced May 2nd should position us well for reaching a Phase I readout.

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Company structure

ExpreS2ion Biotech Holding AB is a limited company which has been listed on the Nasdaq First North Growth Market in Sweden since 2016.

ExpreS2ion Biotechnologies ApS was established in 2010 and is the Group's operating subsidiary, with offices and labs in the Technical University of Denmark (DTU) Science Park, located approximately 20 kilometers north of Copenhagen.

		ExpreS2ion BIOTECH HOLDING AB
		Our parent company, ExpreS2ion Biotech Holding AB, was
		formed on November 3, 2015 and listed on the NASDAQ
		First North Growth Market (Ticker: EXPRS2, ISIN:
ExpreS2ion BIOTECHNOLOGIES APS		SE0008348262) in Stockholm in 2016. The company's only
100%	business activities are to own the subsidiary ExpreS2ion
ExpreS2ion Biotechnologies ApS was founded	Biotechnologies ApS. The parent company's Certified
in 2010 and is the Group's operating subsidiary.		Advisor is Svensk Kapitalmarknadsgranskning AB (SKMG).
It is 100% owned by ExpreS2ion Biotech Holding

AB. The operating subsidiary's ExpreS2-platform was developed in the early 2000's, and with its patent in 2010 the company ExpreS2ion Biotechnologies ApS was formed. It is the main operational entity of the Group, and where all of the staff are employed.

AdaptVac ApS was established in 2017 as a joint venture between ExpreS2ion Biotechnologies and a group of scientists from the Institute of Immunology and Microbiology at the University of Copenhagen. The scientists own their share of AdaptVac through NextGen Vaccines ApS, a joint holding company.

34%

ADAPTVAC

APS

66%

NEXTGEN

VACCINES APS

AdaptVac ApS
AdaptVac Aps was formed in 2017 as a 50/50 joint venture between
ExpreS2ion Biotechnologies ApS and NextGen Vaccines, a University
of Copenhagen spin-out. The goal of the Joint Venture was to create
a world class unit for the development of highly competitive vaccines
and therapeutics against infectious diseases, cancer, and
immunological disorders. The combination of ExpreS2ion's
proprietary insect cell expression technology, ExpreS2, and NextGen's
unique expertise in proprietary Virus-Like Particle (VLP) technology
makes AdaptVac a strong and versatile player in the field of new
vaccines and immune therapy. The Company's ownership stake in
AdaptVac was reduced from 50 percent to 34 percent in February of
2021 upon exercise of the option to in-license the HER2-cVLP breast
cancer vaccine candidate today known as ES2B-C001.	4

EXPRES2ION 2024 FIRST QUARTER INTERIM REPORT

Business model

Vision and mission of the Company

ExpreS2ion is a biotechnology company that develops innovative vaccines for a healthier world. We want to transform healthcare by developing novel vaccines that are life-saving and improving quality of life across the World.

Business model

The Company operates on a dual business model, consisting of novel pipeline development and contract research activities.

The primary objective is to establish a distinctive and competitive pipeline of preventive and therapeutic vaccine products. The Company is diligently building a portfolio of preclinical and later- stage clinical biopharmaceutical drug and vaccine candidates. Initially, ExpreS2ion conducts its own research, preclinical, and early clinical development work (proof-of- concept) before considering out-licensing opportunities. For instance, an agreement

was reached with Bavarian Nordic in 2020, wherein Bavarian Nordic assumes all future development costs for the COVID-19 vaccine programme and may provide certain milestones and royalties. Another collaborative effort is evident in the research collaboration agreement with Evaxion Biotech A/S, wherein research costs and IP licensing are shared equally between the parties, focusing on a novel CMV vaccine candidate.

Simultaneously, the Company generates revenue through its Contract Research Organisation (CRO) in several ways:

• Fee-for-servicecontract research and products related to recombinant protein expression.
• Outlicensing the ExpreS2 platform to research institutes and pharmaceutical companies engaged in biopharmaceutical drug and vaccine development, either independently or in partnership with the Company.

• Selling ExpreS2 test kits and reagents for research purposes or diagnostic applications

This dual model brings about short-term revenue from the CRO business, which involves offering clinical trial services within medical research development. Meanwhile, the pharmaceutical products developed using the Company's technology have the potential to generate future royalties, license fees, and milestone payments.

The Company firmly believes that prioritising an in-house pipeline of biopharmaceutical drug and vaccine candidates, along with strategic development collaborations while maintaining its CRO business, positions it favourably to generate revenue and create value for both the Company and its shareholders in the long term.

As of now, the Company's activities are

focused on pharmaceutical development, and it has not engaged in sales of approved pharmaceuticals or medications developed in conjunction with a development partner.

Strategy and growth

ExpreS2ion aims to develop the pipeline of biopharmaceutical candidates further by adding additional vaccine projects while continuing preclinical and early clinical development work on existing projects. The Company targets human Proof-of- Concept since successful studies according to the Company can maximize opportunities for qualitative partnerships and collaborations for further development. Partnering early in the process is also an option for progressing pipeline projects, by using a partner's resources, which among others can be technology, knowledge, or financing. The Company also aims to improve the technology platform further to ensure competitiveness. This is done by improving

the ExpreS2 system, potentially adding relevant compatible technologies, and continuing to sell licenses for the use of the ExpreS2 platform.

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Vaccine pipeline

Discovery

Lead opt

CTA-enabling

ES2B-C001	Oncology	Tox studies and manufacturing
HER2+ breast cancer (therapeutic)

ES2B-I002	Infectious
Cytomegalovirus	Lead optimization
disease
(prevention)

Exploratory

Undisclosed	Discovery

Ph 1

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Ph 2

Ph 3

Market size

>€10

Billion1

>€2

Billion2

>€2

Billion3

1 Global Data, 2022, for HER2+ breast cancer	6
2	Market estimate from Moderna, 41st Annual J.P. Morgan Healthcare Conference (Presentation)
3	Based on data for global market for existing therapies from Future Market Insights

Pipeline description

BREAST CANCER

Breast cancer is a widespread oncology indication affecting more than 1.3 million people worldwide annually, resulting in more than 450,000 deaths1. The most common treatment today is based on monoclonal antibodies, where the dominating therapies Herceptin (trastuzumab) and Perjeta (pertuzumab) generate annual global sales of USD 7 billion. The target product profile of our lead breast cancer project, ES2B-C001(HER2-cVLP), is tailored to be highly competitive both in terms of cost and efficacy, thus aiming at a significant market share.

In February 2021, ExpreS2ion signed a patent license agreement with AdaptVac whereby ExpreS2ion exclusively licensed in AV001 (renamed ES2B-C001). This gives ExpreS2ion full control over

and responsibility for driving this valuable asset forward, hereby realising the very significant value of this project. At the end of 2021, ExpreS2ion's candidate demonstrated strong tumour-growth inhibiting effect in a mice models, thus reaching an important pre-clinical milestone ahead of schedule. Additionally, anti-HER2 antibodies from these studies were found to effectively inhibit tumour growth in human cancer cells. The candidate also demonstrated proof-of-concept in HER2-transgenic preventive as well as therapeutic tumour mice models, thus reaching a further important pre- clinical milestone. ExpreS2ion is now completing the preclinical safety studies.

On 17 August 2023, ExpreS2ion's Board decided to assess strategic options for ES2B-C001 aimed at conserving capital resources to further advance the Company's exploratory vaccine pipeline and technology platforms. Since that announcement, the Company has been investigating various options for the asset, including partnering with the aim of sharing the development costs and upside in the clinical Phase I study plans that come at a significantly lower cost than what was previously planned. The Company has continued preclinical development, including finalising the safety studies and GMP manufacturing with the goal of preparing a clinical trial application (CTA) package. Additional financing is required to complete the Phase I trial.

By the end of the year, we were making preparations to produce the final drug substance, which is the manufacturing of the active pharmaceutical ingredient. The remaining steps include assembly into the final drug product, which includes inactive ingredients as well as placement in the final form - a vial - with all appropriate

packaging, labeling and quality control tests. Moreover, the final report for the preclinical safety studies were completed in April 2024.

CYTOMEGALOVIRUS

The company has signed a Vaccine Discovery Collaboration Agreement with Evaxion Biotech A/S (NASDAQ: EVAX) for the joint development of a novel cytomegalovirus (CMV) vaccine candidate. The collaboration combines ExpreS2ion's ExpreS2 platform and resources for vaccine development and production with Evaxion's proprietary EDEN and RAVENTM artificial intelligence (AI) platforms to design a next generation vaccine candidate that elicit both humoral/antibody and cellular responses.

The aim of the collaboration is to, before the end of 2025, select a novel CMV lead vaccine candidate, which ExpreS2ion has the exclusive right to license under a potential Development and Commercialization Agreement. The research costs and IP licensing for the collaboration project will be divided 50/50 between the parties until 2025, with all costs expected to be covered by each party's existing budget.

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The design and discovery phase of the collaboration will be driven by Evaxion's proprietary AI platforms,

and antigen constructs will be produced by ExpreS2ion

in the company's ExpreS2 platform, followed by assessments in Evaxion's state-of-the-artin vivo vaccine models.

A potential future Development and Commercialisation Agreement for the jointly discovered CMV lead vaccine candidate is expected to include an upfront payment and future milestone payments to Evaxion from ExpreS2ion not exceeding a six-digit USD amount, as well as sub-licensing royalty to Evaxion from ExpreS2ion based on mid to lower two-digit percentage range of third-party licensee income depending on the clinical development stage of the CMV asset at the time of sublicensing.

In 2023, our progress was marked by significant achievements across various key milestones. First and foremost, we successfully established a Standard Operating Procedure (SOP) for High Throughput Method Analysis, streamlining the selection of antigens. This milestone ensures a systematic and efficient approach to our antigen identification process. Additionally, our team has made considerable advancements in platform optimisation. Notably, the valuable learnings accumulated have been integrated into the design of the CMV vaccine construct, a pivotal step towards ensuring the effectiveness of our vaccine. Furthermore, the selection of antigens,

achieved through a combination of Evaxion's cutting-

edge EDEN AI platform and extensive literature review, represents a crucial advancement in our vaccine development strategy.

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1Tao,2015:www.ncbi.nlm.nih.gov/pubmed/25543329

Collaboration projects

MucoVax mucosal influenza vaccine candidate

The MucoVax consortium, a collaboration between ExpreS2ion and University of Copenhagen, has been awarded an Innovation Fund Denmark (IFD) Grand Solutions grant for the development of new platforms for universal mucosal vaccines in a 5- year research project. The award funding covers 71% of the research project and amounts to 29 MDKK (approx. 43 MSEK), of which ExpreS2ion directly is funded with 9.6 MDKK (approx. 14 MSEK). The IFD investment funds 67% of ExpreS2ion's share of the research project budget.

The aim of the grant is to support the MucoVax consortium in the development of new platforms for universal mucosal vaccines, including performing animal models to test in vivo novel influenza vaccines delivered intranasally. The ambitious aim is to combine ExpreS2ion's unique ExpreS2 protein production system with the fundamental knowledge in immunology and microbiology of the University of Copenhagen including novel and advanced vaccine platforms.

The MucoVax consortium members are world- leading experts in their respective fields, covering all relevant areas of viral research and vaccine development required for preclinical development of a universal mucosal influenza vaccine. This includes pre-clinical and clinically validated experience from working with malaria pathogens and the SARS-CoV2corona-virus, applying ExpreS2ion's Drosophila S2 insect cell expression system, and unique know-how in exploration of adjuvants and virus-like particle (VLP) technologies.

In 2023, ExpreS2ion made significant progress in the development of the MucoVax mucosal influenza vaccine. Notably, in March, the MucoVax consortium, comprised of ExpreS2ion and the University of Copenhagen, secured an Innovation Fund Denmark (IFD) Grand Solutions grant, marking the initiation of a 5-year research collaboration between ExpreS2ion and the University of Copenhagen. The grant, which covers 71% of the research project, amounting to 29 MDKK (approx. 43 MSEK), supports the development of novel platforms for universal mucosal vaccines. Subsequently, ExpreS2ion

commenced the project, focusing on the design of antigens, mucosal delivery platforms, and constructs.

INDIGO influenza vaccine candidate

The international next-generation influenza vaccine consortium INDIGO, led by the University of Amsterdam with ExpreS2ion as a participating member, is developing a next-generation influenza vaccine in a large collaboration between public and private R&D organisations from the EU, India, and the United States. The project has been awarded a 10 MEUR Horizon 2020 grant from the EU, of which ExpreS2ion's participation was directly awarded 0.6 MEUR.

The INDIGO consortium plans to carry out the preclinical and clinical development of the project, which contains two novel influenza vaccine concepts, including the application of a novel potent adjuvant by LiteVax BV, the Netherlands, as well as the use of the ExpreS2 platform for antigen production by ExpreS2ion. The aim is to create an influenza vaccine that meets the requirements of global vaccination, i.e. to achieve <10% instead of 60% non-responders, combined with a lower manufacturing cost and better accessibility.

University of Oxford malaria vaccine candidates

Our ExpreS2 technology continues to play a pivotal role in the success of four clinical-stage malaria vaccine projects led by the University of Oxford, each demonstrating significant progress. These advancements represent a significant

EXPRES2ION 2024 FIRST QUARTER INTERIM REPORT

stride forward in malaria vaccine development, with ExpreS2ion's technology contributing to the manufacturing process based on Drosophila

S2 insect cells. Importantly, these initiatives are financed by grants awarded to the University of Oxford and its collaborative partners. Ongoing efforts aim to facilitate further development and clinical testing in developing countries.

See the table on the next page for an overview of the status of the seven ongoing clinical trials sponsored by University of Oxford using antigens produced in the ExpreS2 system.

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University of Oxford malaria vaccine candidates

Trial					Year
abbreviation	Phase	Sites	Vaccines in trial	Trial status	started
VAC089	Ia	Oxford, UK	RH5.1 in Matrix-M	Vaccinations	2023
			R78C in Matrix-M	on-going
VAC086	Ib	MRC Unit, The	RH5.2 VLP in Matrix-M	Vaccinations	2023
		Gambia	R21 VLP in Matrix-M	on-going
VAC091	IIb	IRSS CRUN,	RH5.1 in Matrix-M	Vaccinations	2023
		Burkina Faso	RH5.2-VLP in Matrix-M	on-going
BIO-001	I/IIa	Oxford, UK	RH5.2 VLP in Matrix-M	Screening &	2023
			RH5.1 in Matrix-M	vaccinations
				on-going
BIO-002	I	Sheffield, UK	RH5.1 in Matrix-M	Vaccinations	2023
				on-going
BIO-003	I	IHI Bagamoyo,	RH5.1 and R78C with	In set-up	N/A
		Tanzania	Matrix-M

VICI-Disease consortium

ExpreS2ion is pleased to have secured an 8 million EUR Horizon Europe grant for the VICI-Disease consortium, aimed at developing a vaccine against the Nipah virus. The grant, where ExpreS2ion's direct contribution constitutes 53% of the project costs, aligns strategically with our goal of advancing assets efficiently using the ExpreS2 platform. This non-dilutive funding is of significant importance, dovetailing seamlessly with ExpreS2ion's new strategic direction, which prioritises shorter development timelines and cost-effective approaches to value creation.

The collaborative effort involves leading experts within the VICI-Disease consortium, including ExpreS2ion, AdaptVac, Friedrich-Loeffler-Institut, Radboud University Medical Center, and University of Copenhagen, where the latter serves as the project coordinator. The consortium's collective expertise spans critical areas of viral vaccine

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ExpreS2TM platform technology

The ExpreS2 technology platform

The Company's ExpreS2 platform has been used successfully for the development and production of hard-to-express proteins for over a decade. It has a great track record, with over 500 proteins expressed and a success rate above 90 percent. Additional advantages include a rapid delivery process of 3-6 months, and a high batch-to-batch consistency.

The platform is now validated in a clinical Phase III trial with the ABNCoV2 COVID-19 vaccine. Furthermore, the platform is used in the Company's own ES2B-C001 HER2 breast cancer vaccine programme, as well as in

In addition to its current advantages, the ExpreS2 platform is also in the process of being upgraded with unique and genetically engineered cell lines, such as the HighMan- S2 . With these cell lines, the proteins expressed are given improved characteristics such as the facilitation of higher immunization levels compared to regular versions of the same proteins.

ExpreS2 Platform Strengths

1.

Significantly less costly and time- consuming than alternative methods, which is an important competitive advantage, considering time-to-market and patent expiry. It also makes the platform particularly valuable for the development of diagnostics and vaccines in epidemic or pandemic situations where speed is of the essence.

2.

Generates higher yields, i.e. amount of protein per manufacturing batch, compared to competing systems.

several Malaria vaccine partner projects and the influenza vaccine project developed within the INDIGO consortium. The platform is also used in ExpreS2ion's CRO services, which will be increasingly used to drive value generation in the Company's pipeline development projects going forward.

3.

Provides homogeneous manufacturing batches, a requirement in pharmaceutical development. The platform includes the Company's patented expression vectors which were developed, among other things, to make it possible for the cells to generate higher yields.

4.

Since 2019 the Company's offering to the biopharma sector includes glycoengineered S2 cell lines under the GlycoX-S2 brand. This allows for functional modification, e.g. by enhancing immunogenicity or improving pharmacokinetics.

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