BioSenic SA

Major Shareholding Notification • Jan 3, 2025

Transparency notifications received from ABO Infinium Americas OpCo LTD.

Article 14 of the Law of 2 May 2007 on disclosure of major holdings

Mont-Saint-Guibert, Belgium, January 3, 2025, 17:30 – BIOSENIC (Euronext Brussels and Paris: BIOS) announces that it has received three transparency notifications from ABO Infinium Americas OpCo LTD. The details of the notifications are set out below and the full text can be consulted on the website of BioSenic, under the heading "Major shareholders & transparency notices".

The first transparency notification indicates that the voting rights attached to BioSenic's shares held by ABO Infinium Americas OpCo LTD. have crossed above the threshold of 15% as a result of the acquisition of shares of BioSenic.

The notification received from ABO Infinium Americas OpCo LTD. dated 16 December 2024 contains the following information:

• Reason for the notification: Acquisition or transfer of voting securities or voting rights

• Notification by: A parent company or controlling person
• Person subject to the notification requirement:
  • ABO Infinium Americas OpCo LTD.
  • ABO Securities
  • Omega Financial Corporation
  • Mr Pierre Vannineuse
• Transaction date: 16 December 2024
• Threshold that is crossed: 15%
• Denominator: 323 931 864
• Notified details:

Voting rights	Previous notification	After the transaction
Holders of voting rights	# of voting rights	# of voting rights	% of voting rights
Mr Pierre Vannineuse	0	0	0,00%
Omega Financial Corporation	0	0	0,00%
ABO Securities	0	0	0,00%
ABO Infinium Americas OpCo LTD.	14 285 714	50 043 122	15,45%
Total voting rights	14 285 714	50 043 122	15,45%

• Full chain of controlled undertakings through which the holding is effectively held: ABO Infinium Americas OpCo LTD. (303 Shriley Street, Nassau, Bahamas) is 100% owned by ABO Securities (71 Fort Street, Georges Town,

Grand Cayman, Cayman Island). ABO Securities is 100% owned by Omega Financial Corporation (71 Fort Street, Georges Town, Grand Cayman, Cayman Island). Omega Financial Corporation is 100% owned by Pierre Vannineuse.

The second transparency notification indicates that the voting rights attached to BioSenic's shares held by ABO Infinium Americas OpCo LTD. have crossed below the threshold of 10% as a result of transfer of shares of BioSenic.

The notification received from ABO Infinium Americas OpCo LTD. dated 18 December 2024 contains the following information:

• Reason for the notification: Acquisition or transfer of voting securities or voting rights

• Notification by: A parent company or controlling person
• Person subject to the notification requirement:
  • ABO Infinium Americas OpCo LTD.
  • ABO Securities
  • Omega Financial Corporation
  • Mr Pierre Vannineuse
• Transaction date: 18 December 2024
• Threshold that is crossed: 10%
• Denominator: 323 931 864
• Notified details:

Voting rights	Previous notification	After the transaction
Holders of voting rights	# of voting rights	# of voting rights	% of voting rights
Mr Pierre Vannineuse	0	0	0,00%
Omega Financial Corporation	0	0	0,00%
ABO Securities	0	0	0,00%
ABO Infinium Americas OpCo LTD.	50 043 122	29 304 250	9,05%
Total voting rights	50 043 122	29 304 250	9,05%

• Full chain of controlled undertakings through which the holding is effectively held: ABO Infinium Americas OpCo LTD. (303 Shriley Street, Nassau, Bahamas) is 100% owned by ABO Securities (71 Fort Street, Georges Town, Grand Cayman, Cayman Island). ABO Securities is 100% owned by Omega Financial Corporation (71 Fort Street, Georges Town, Grand Cayman, Cayman Island). Omega Financial Corporation is 100% owned by Pierre Vannineuse.

The third transparency notification indicates that the voting rights attached to BioSenic's shares held by ABO Infinium Americas OpCo LTD. have crossed below the threshold of 5% as a result of transfer of shares of BioSenic.

The notification received from ABO Infinium Americas OpCo LTD. dated 27 December 2024 contains the following information:

• Reason for the notification:

  • Lowering the minimum threshold
  • Acquisition or Transfer of voting securities or voting rights

• Notification by: A parent company or controlling person

• Person subject to the notification requirement:
  • ABO Infinium Americas OpCo LTD.
  • ABO Securities
  • Omega Financial Corporation
  • Mr Pierre Vannineuse
• Transaction date: 27 December 2024
• Threshold that is crossed: 5%
• Denominator: 323 931 864
• Full chain of controlled undertakings through which the holding is effectively held: ABO Infinium Americas OpCo LTD. (303 Shriley Street, Nassau, Bahamas) is 100% owned by ABO Securities (71 Fort Street, Georges Town, Grand Cayman, Cayman Island). ABO Securities is 100% owned by Omega Financial Corporation (71 Fort Street, Georges Town, Grand Cayman, Cayman Island). Omega Financial Corporation is 100% owned by Pierre Vannineuse.

About BioSenic

BioSenic is a leading biotech company specializing in the development of clinical assets issued from its Medsenic's arsenic trioxide (ATO) platform. Key target indications for the autoimmune platform include graft-versus-host-disease (GvHD), systemic lupus erythematosus (SLE), and now systemic sclerosis (SSc).

Following the merger in October 2022, BioSenic combined the strategic positionings and strengths of Medsenic and Bone Therapeutics. The merger specifically enables Medsenic/Biosenic to develop an entirely new arsenal of various anti-inflammatory and anti-autoimmune formulations using the immunomodulatory properties of ATO/oral ATO (OATO).

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 provides derived active products with immunomodulatory properties and fundamental effects on the activated cells of the immune system. One direct application is its use in onco-immunology to treat GvHD (Graft-versus-Host Disease) in its chronic, established stage. cGvHD is one of the most common and clinically significant complications affecting long-term survival of allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Medsenic has been successful in a phase 2 trial with its intravenous formulation, Arscimed®, which has orphan drug designation status by FDA and EMA. The company is heading towards an international phase 3 confirmatory study, with its new, IP-protected, OATO formulation. Another selected target is moderate-to-severe forms of systemic lupus erythematosus (SLE), using the same oral formulation. ATO has shown good safety and significant clinical efficacy on several affected organs (skin, mucosae, and the gastrointestinal tract). Systemic sclerosis is now full part of the clinical pipeline of Medsenic/BioSenic. This serious chronic disease badly affects skin, lungs, or vascularization, and has no current effective treatment. Preclinical studies on pertinent animal models are positive, giving good grounds to launch a phase 2 clinical protocol, using new immunomodulatory formulations of APIs recognized to be active on the immune system.

The company is currently focusing its present R&D and clinical activities on a selective, accelerated development of its autoimmune platform.

For further information, please contact:

BioSenic SA

Finsys Management SRL, represented by its permanent representative Jean-Luc Vandebroek, managing director ad interim investorrelations@biosenic.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.

BioSenic S.A. • Rue Granbonpré 11 - Building H (box 24) • 1435 Mont-St-Guibert • Belgium (Europe) • Phone: +32 (0)493 09 73 66 www.biosenic.com