PRESS RELEASE – REGULATED INFORMATION Mont-Saint-Guibert, Belgium, March 29, 2024, 7.00 am CEST – BIOSENIC (Euronext Brussels and Paris: BIOS), the clinical-stage company specializing in serious autoimmune and inflammatory diseases and cell therapy, today announces an increase in the total number of voting rights and shares as a result of the issuance of new shares. The following information is published in accordance with Article 15 of the Belgian law of 2 May 2007 on the publication of major shareholdings in issuers whose shares are admitted to trading on regulated market. Total amount of share capital on February 29, 2024EUR 35 850 669Total number of shares with voting rights on February 29, 2024183 525 722Total number of new shares issued between February 29, 2024 and March 29, 2024 9 347 826Total amount of share capital on March 29, 2024EUR 36 050 669Total number of shares with voting rights on March 29, 2024192 873 548Total number of voting rights (denominator) on March 29, 2024192 873 548Total number of attributed warrants1 161 556Total number of convertible bonds outstanding958Total number of remaining convertible bonds commitments30Total number of shares with voting rights that can be issued following the exercise of the attributed warrants, remaining convertible bonds commitments and the conversion of the convertible bonds145.143.720 (1) (1) 1 161 556 shares could be issued in case all 1 161 556 attributed warrants were exercised.285 714 shares could be issued in case all 800 convertible bonds outstanding, issued in the private placement on 6 May 2020, were converted into shares based on the predetermined conversion price of EUR 7.00.143 696 450 shares could be issued in case all 30 convertible bonds commitments remaining and all 158 convertible bonds outstanding of the two ABO convertible bonds programs were exercised and converted into shares based on the conversion price of EUR 0,020425 (95% of the Volume-Weighted-Averaged-Price of BioSenic’s shares on 25 March 2024). About BioSenic BioSenic is a biotech company specializing in the clinical development of autoimmune disease therapies. Following a reverse merger in October 2022, BioSenic combined its strategic positioning, key strengths and strong IP to develop products along two tracks, separately and in combination. The first platform leverages immunomodulatory properties of arsenic trioxide (ATO) for an entirely new arsenal of formulations, including oral delivery (OATO), for anti-inflammatory and anti-autoimmune indications such as chronic graft-versus-host disease (cGvHD), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). In parallel, BioSenic develops innovative products through a second platform that includes cell therapies and strong IP protection for tissue repair technologies. BioSenic is based in the Louvain-la-Neuve Science Park in Mont-Saint-Guibert, Belgium. Further information is available at http://www.biosenic.com. About the main Medsenic/BioSenic technology platform The ATO platform has immunomodulatory properties with fundamental effects on the activated cells of the immune system. One direct application is its use in autoimmunity to treat in its chronic, established stage. Chronic GvHD is one of the most common and clinically significant complicationsaffecting long-term survival of allogeneic hematopoietic stem cell transplantation (allo-HSCT), a curative treatment for patients with serious blood diseases, including cancers.BioSenic’s intravenous ATO formulation, Arscimed®, has orphan drug designation status by FDA and EMA, and it has shown good safety and significant clinical efficacy for skin, mucosae, and the gastrointestinal tract in an early Phase 2a study. The company is planning a confirmatory international Phase 3 study with its oral ATO (OATO) formulation. OATO will also target moderate-to-severe forms of SLE. BioSenic is also developing a new IP-protected OATO formulation for the treatment of SSc, a serious chronic disease that affects skin, lungs or vascularization, and has no current effective treatment. Preclinical studies on pertinent animal models support the launch of a Phase 2 clinical trial. ALLOB is an allogeneic cell therapy platform made of differentiated, bone marrow-sourced mesenchymal stromal cells (MSCs), which can be stored at the point-of-use in hospitals. ALLOB represents a unique and proprietary approach to organ repair, and specifically to bone regeneration, by turning undifferentiated MSCs from healthy donors into bone-forming cells at the site of injury. BioSenic is studying the results of a Phase 2 trial to optimise the efficacy of ALLOB by determining the best timing for therapeutic intervention and seeking partners to continue the development of the promising underlying therapy strategies. The company is also exploring partnerships at all levels for its JTA-004 viscosupplement for a severe inflammatory subtype of osteoarthritis, following a positive post hoc analysis of Phase 3 data demonstrating safety and efficacy in support of this licensing. For further information, please contact: BioSenic SAFrançois Rieger, PhD, CEOTel: +33 (0)671 73 31 59investorrelations@biosenic.com International Media Enquiries:IB CommunicationsMichelle BoxallTel: +44 (0)20 8943 4685michelle@ibcomms.agency French Investor Enquiries:Seitosei ActifinGhislaine GasparettoTel: +33 (0)1 56 88 11 22ghislaine.gasparetto@seitosei-actifin.com Michael Scholzemichael.scholze@seitosei-actifin.com Certain statements, beliefs and opinions in this press release are forward-looking, which reflect the company or, as appropriate, the company directors’ current expectations and projections about future events. By their nature, forward-looking statements involve a number of risks, uncertainties and assumptions that could cause actual results or events to differ materially from those expressed or implied by the forward-looking statements. These risks, uncertainties and assumptions could adversely affect the outcome and financial effects of the plans and events described herein. A multitude of factors including, but not limited to, changes in demand, competition and technology, can cause actual events, performance or results to differ significantly from any anticipated development. Forward looking statements contained in this press release regarding past trends or activities should not be taken as a representation that such trends or activities will continue in the future. As a result, the company expressly disclaims any obligation or undertaking to release any update or revisions to any forward-looking statements in this press release as a result of any change in expectations or any change in events, conditions, assumptions or circumstances on which these forward-looking statements are based. Neither the company nor its advisers or representatives nor any of its subsidiary undertakings or any such person’s officers or employees guarantees that the assumptions underlying such forward-looking statements are free from errors nor does either accept any responsibility for the future accuracy of the forward-looking statements contained in this press release or the actual occurrence of the forecasted developments. You should not place undue reliance on forward-looking statements, which speak only as of the date of this press release.