Acacia Pharma to Postpone Publication of its Results for the Full Year 2021, Scheduled on 31 March 2022

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30 March 2022, 6:00 p.m. (Brussels time)

Cambridge, UK and Indianapolis, US – Acacia Pharma Group plc (“Acacia Pharma” or the “Company”) (EURONEXT: ACPH), announces that it will not publish its results for the full year to end December 2021 on 31 March 2022 as originally scheduled.

This comes as a result of the changes in regulatory requirements following Brexit. The Company is required under Belgian law to have its accounts audited by either an EU audit firm or a third country audit firm registered in Belgium. Following Brexit, the Company’s statutory auditor PwC UK ceased to be an EU audit firm on 30 June 2021.

The Company has been informed that there is currently no legal mechanism for PwC UK to register as a third country audit firm in Belgium; the Company is therefore required to also have its accounts audited by PwC Belgium. A new date for the publication of its results will be set and these will be released before the end of April 2022 as required under the applicable rules.

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About Acacia Pharma

Acacia Pharma is a hospital pharmaceutical company focused on the development and commercialization of new products aimed at improving the care of patients undergoing significant treatments such as surgery, other invasive procedures, or cancer chemotherapy. The Company has identified important and commercially attractive unmet needs in these areas that its product portfolio aims to address.

Barhemsys® (amisulpride) injection is a selective dopamine (D₂ and D₃) receptor antagonist approved and available in the US for the treatment and prevention of postoperative nausea & vomiting (PONV) in adult patients.

Please see full prescribing information, including Important Safety Information, at .

Byfavo® (remimazolam) for injection, is an IV benzodiazepine sedative approved and available in the US for the induction and maintenance of procedural sedation in adults undergoing procedures lasting 30 minutes or less. Byfavo is in-licensed from Paion UK Limited for the US market.

Please see full prescribing information, including Important Safety Information and Boxed Warning, at .

APD403 (intravenous and oral amisulpride), a selective dopamine antagonist for chemotherapy induced nausea & vomiting (CINV) has successfully completed one proof-of-concept and one Phase 2 dose-ranging study in patients receiving highly emetogenic chemotherapy.

Acacia Pharma has its US headquarters in Indianapolis, IN and its R&D operations are centred in Cambridge, UK. The Company is listed on the Euronext Brussels exchange under the ISIN code GB00BYWF9Y76 and ticker symbol ACPH.

This release is intended for investors and media only.

Forward looking statement

This announcement includes forward-looking statements, which are based on current expectations and projections about future events. These statements may include, without limitation, any statements preceded by, followed by or including words such as “believe”, “expect”, “intend”, “may”, “plan”, “will”, “should”, “could” and other words and terms of similar meaning or the negative thereof. Forward-looking statements may and often do differ materially from actual results. These forward-looking statements are subject to risks, uncertainties and assumptions about the Company and its subsidiaries and investments, including, among other things, the development of its business, trends in its operating industry, and future capital expenditures and acquisitions. By their nature, forward-looking statements involve risk and uncertainty because they relate to future events and circumstances. Any forward-looking statements reflect the Company's current view with respect to future events and are subject to risks relating to future events and other risks, uncertainties and assumptions relating to the Group's business, results of operations, financial position, prospectus, growth or strategies and the industry in which it operates. Save as required by law or applicable regulation, the Company and its affiliates expressly disclaim any obligation or undertaking to update, review or revise any forward-looking statement contained in this announcement whether as a result of new information, future developments or otherwise. Forward-looking statements speak only as of the date they are made.