MaaT Pharma : Inside Information / Other news releases

Press release

MaaT Pharma Announces Long Term Follow-Up Data for MaaT013 in Early Access Program to be Presented at the Upcoming EBMT Conference

• Oral presentation will highlight new data in Early Access Program (EAP) for patients with acute Graft-vs-Host Disease (aGvHD) treated with MaaT013.
• This is the seventh year that MaaT Pharma's abstracts have been chosen for presentation at the EBMT Annual Meeting, confirming the Company's leadership in the field of hemato-oncology/ microbiome.

Lyon, France, March 12th, 2024, 7:30am CET - MaaT Pharma(EURONEXT: MAAT - the "Company"), a clinical-stagebiotechnology company and a leader in the development of Microbiome Ecosystem TherapiesTM (MET) dedicated to enhancing survival for patients with cancer, will present extended results from its Early Access Program for patients with aGvHD that were treated with MaaT013 and, for the first time, Overall Survival data after 12 months in more patients. The data will be shared during an oral presentation at the 50thAnnual Meeting of the European Society for Blood and Marrow Transplantation held in Glasgow, UK, from April 14-17, 2024. Details from the presentation will be disclosed in a press release on April 17th, 2024, in compliance with the conference embargo policy.

Aligned with its mission to enhance the survival of cancer patients, MaaT Pharma has been actively involved in the EAP in Europe since 2019. The Company has consistently presented real-world data from its EAP at major hematology conferences over the past four years. At each data communication point, EAP results confirm previous findings, that MaaT013 has an impact on overall survival (OS) when the primary endpoint (gastrointestinal Overall Response Rate at D28) is achieved (see press release on data presented at 2023 ASH1annual meeting). To date, over 220 patients have been treated with MaaT013 in Europe in clinical trials and the EAP.

In the context of the EAP, the Company has bolstered its manufacturing & supply chain, ensuring timely and safe provision of MaaT013 to 38 stem cell transplant hospitals across 6 European countries: Austria, Belgium, France, Germany, Italy, and Spain.

Dr. Michael Loschi, hematologist at Nice Hospital in France emphasized "we are enrolling in the EAP due to the lack of third-linetreatment options for patients with aGvHD who are unresponsive to corticosteroids and ruxolitinib. We receive MaaT013 within 48 hours following the request via a simple procedure for EAP. This has transformed our routine to treating patients with aGvHD and significantly improved their quality of life. The data presented at ASH align with our observations in clinical practice. We've observed superior

1 American Society of Hematology

1/2

Press release

efficacy with more complete responses2 in gastrointestinal aGvHD and less toxicity when compared to other immune suppressive drugs. "

"I find the procedure in EAP to be quite straightforward" shared Dr. Alexander Schauwvlieghe, hematologist at AZ Sint-JanBrugge AV Hospital in Belgium. "I'm a strong advocate for gut microbiome- based treatments, such as MaaT013, that prioritize immune restoration in GvHD. This approach helps maintain the patient's immune function, reducing the risk of infectious complications and relapse."

A pivotal Phase 3 trial (n=75) evaluating MaaT013 (ARES trial - NCT04769895)in patients with corticosteroid and ruxolitinib-refractory gastrointestinal aGvHD is currently ongoing to confirm the results from the EAP. The Company previously shared the positive review by DSMB3for the Phase 3 ARES trial, including a favorable benefit/risk ratio, with "high efficacy and low toxicity."

Details of Oral Presentation at EBMT 2024

• Title:Pooled Fecal Allogenic Microbiotherapy for Refractory Gastrointestinal AcuteGraft-Versus-
  Host Disease: Results from Early Access Program in Europe
• Abstract number: OS13-07
• Session: OS13 Oral Session 13 | GVHD
• Session Date/Time: Wednesday, April 17, 10:30 - 11:45
• Location: Hall 5

---

About MaaT Pharma

MaaT Pharma, a leading clinical-stage biotechnology company, has established a complete approach to restoring patient-microbiome symbiosis in oncology. Committed to treating cancer and graft-versus-host disease (GvHD), a serious complication of allogeneic stem cell transplantation, MaaT Pharma initiated an open-label,single-arm Phase 3 clinical trial in patients with acute GvHD, building on the positive results of its Phase 2 proof-of-concept. Its powerful discovery and analysis platform, gutPrint®, enables the identification of novel disease targets, evaluation of drug candidates, and identification of biomarkers for microbiome-related conditions. The company's Microbiome Ecosystem Therapies are produced through a standardized cGMP manufacturing and quality control process to safely deliver the full diversity of the microbiome in liquid and oral formulations. MaaT Pharma benefits from the commitment of world-leading scientists and established relationships with regulators to support the integration of the use of microbiome therapies in clinical practice. MaaT Pharma is listed on Euronext Paris (ticker: MAAT).

Forward-looking Statements

All statements other than statements of historical fact included in this press release about future events are subject to (i) change without notice and (ii) factors beyond the Company's control. These statements may include, without limitation, any statements preceded by, followed by or including words such as "target," "believe," "expect," "aim," "intend," "may," "anticipate," "estimate," "plan," "project," "will," "can have," "likely," "should," "would," "could" and other words and terms of similar meaning or the negative thereof. Forward-looking statements are subject to inherent risks and uncertainties beyond the Company's control that could cause the Company's actual results or performance to be materially different from the expected results or performance expressed or implied by such forward-looking statements.

Contacts
MaaT Pharma - Investor Relations	MaaT Pharma - Media Relations	Trophic Communications - Corporate
Guilhaume DEBROAS, Ph.D.	Pauline RICHAUD	Communications
Head of Investor Relations	Senior PR & Corporate Communications	Jacob VERGHESE or
[phone]	Manager	Priscillia PERRIN
[e-mail]	[phone]	[phone]
	[e-mail]	[e-mail]

1. No evidence of aGvHD
2. Data Safety Monitoring Board

2/2