ACACIA PHARMA ANNOUNCES SUPPORTIVE CARDIAC SAFETY DATA FOR BARHEMSYS™

Cambridge, UK and Indianapolis, US – 22 January 2019: Acacia Pharma Group plc (“Acacia Pharma”, the “Company”) (EURONEXT: ACPH) announces results from its latest study of BARHEMSYS™ (intravenous amisulpride), its anti-emetic currently under FDA review for the management of post-operative nausea & vomiting (PONV).

The study did not find a significant risk for heart rhythm disturbances (arrhythmias) at the highest proposed dose of BARHEMSYS, given alone or in combination with intravenous ondansetron, a widely used PONV therapy with a known effect on the heart trace.

Commenting on the results, Dr Gabriel Fox, Acacia Pharma’s Chief Medical Officer, said: “These latest data give us increased confidence that a single 10 mg dose of BARHEMSYS, which has previously been shown to reduce PONV in clinical trials, will not have a clinically significant effect on the QTc interval, part of the ECG trace which is an important indicator of cardiac risk, even when given with ondansetron. If approved, BARHEMSYS is likely to be given to many patients also receiving ondansetron and it is therefore encouraging that no cardiac or other safety signals were identified with the combination.”

In 30 healthy volunteers, the average maximum effect on the QTc interval of a single 10 mg dose of BARHEMSYS, infused over one minute, was 5.2 milliseconds (90% confidence interval 3.53-6.96 milliseconds). When a standard 4 mg dose of IV ondansetron was given at the same time, the average maximum effect was 7.3 milliseconds (90% confidence interval 5.48-9.16 milliseconds). The internationally agreed threshold level of regulatory concern for serious arrhythmias, such as torsade de pointes, is a mean effect on QTc of 10 milliseconds.

The randomised, double-blind, placebo-controlled, cross-over study, conducted in a specialist Phase 1 trials unit in London, UK, also demonstrated that a second 10 mg dose of BARHEMSYS, given two hours after the first, had a similar pharmacokinetic profile and did not significantly affect the QT or clinical safety profile of the drug. No serious adverse events were reported in the trial and there was no material difference in safety profile between BARHEMSYS (with or without concomitant ondansetron) and placebo.

The most common adverse events were infusion site pain/discomfort, which occurred in eight subjects (28%) with BARHEMSYS alone, nine subjects (30%) with BARHEMSYS plus ondansetron and 12 subjects (40%) with placebo; and headache, which occurred in four subjects (14%) with BARHEMSYS alone, three subjects (10%) with BARHEMSYS plus ondansetron and two subjects (7%) with placebo.

BARHEMSYS is currently under review by FDA for the proposed indications of the treatment of established PONV, whether or not prior prophylaxis was given, and the prevention of PONV, alone or in combination with other antiemetics, with a target action date of May 5, 2019.

Contacts

Acacia Pharma Group plc

Julian Gilbert, CEO

Christine Soden, CFO

Citigate Dewe Rogerson (Financial PR)

Mark Swallow, Shabnam Bashir, David Dible

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About PONV

PONV is a common complication of surgery, occurring in approximately 30% of surgical patients and up to 80% of high-risk patients. It is associated with the use of anaesthetic gases and opioid pain-killers and is particularly common following gynaecological, abdominal, breast, eye and ear operations, especially those lasting an hour or more.

The Company estimates that approximately 65 million surgical procedures are conducted in the US each year that require injectable analgesia and are eligible for antiemetic use to prevent PONV. Based on market research, Acacia Pharma estimates that the total market in the US for prophylactic and rescue treatment comprises an estimated 34 million treatment events annually.

PONV has been ranked as the most undesirable of all surgical complications by patients and contributes significantly to patient anxiety and distress. PONV can delay hospital discharge; result in re-admission after in-patient procedures; and lead to day-case patients being admitted to hospital, all of which can result in significantly increased healthcare costs.

About Acacia Pharma

Acacia Pharma is a hospital pharmaceutical company focused on the development and commercialisation of new nausea & vomiting treatments for surgical and cancer patients. The Group has identified important and commercially attractive unmet needs in nausea & vomiting and has discovered two product candidates based on the same active ingredient, amisulpride, to meet those needs.

The Group's lead project, BARHEMSYS™ for post-operative nausea & vomiting (PONV), has generated positive results in four Phase 3 clinical studies. A New Drug Application (NDA) for BARHEMSYS is under review by the US Food and Drug Administration (FDA). Its sister project, APD403 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 is based in Cambridge, UK and its US operations are centred in Indianapolis, IN. The Company is listed on the Euronext Brussels exchange under the under ISIN code GB00BYWF9Y76 and ticker symbol ACPH.

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.