AT-278

This announcement contains inside information for the purposes of the retained UK version of the EU Market Abuse Regulation (EU) 596/2014 ("UK MAR"). Arecor Therapeutics plc(“Arecor” or the “Company”) Co-development Agreement with US Insulin Pump Device Company for AT278 andSale of Royalty and Technology Access Fees for up to $11 million AT278 (500U/mL) is the only ultra-concentrated and ultra-rapid acting insulin in development designed to enable the next generation of longer-wear and miniaturised automated insulin delivery (AID) systems Arecor and Sequel Med Tech, LLC to commit up to $1.3 million each to fund development work in preparation for pivotal Phase 2 trial for AT278-Insulin Pump programmeStrategic intent is to progress to a broader co-development and commercialisation partnership for Phase 2 trial and beyondNon-dilutive funds raised through the monetisation of Arecor’s royalty rights related to AT220 and milestone and technology access fees related to AT292Cash runway extended to 1H 2027 Cambridge, UK, 25 September 2025: Arecor Therapeutics plc (AIM: AREC), the biopharmaceutical company focused on drug development and delivery in diabetes and other cardiometabolic diseases, has signed a co-development agreement with Sequel Med Tech LLC (“Sequel”), a company developing state-of-the-art insulin delivery technologies, to combine AT278 (500U/mL) with Sequel’s twiist™ Automated Insulin Delivery (AID) system powered by Tidepool, and a royalty financing agreement with Ligand Pharmaceuticals Incorporated (NASDAQ: LGND) (“Ligand”) which will raise non-dilutive capital of up to $11 million (£8.2 million). Sarah Howell, CEO of Arecor Therapeutics said: “The co-development agreement for AT278 and the non-dilutive fund raising via the monetisation agreement are both major strategic achievements for Arecor. The Sequel agreement marks a key milestone, furthering our ambitions to realise AT278’s significant benefits for people living with diabetes as well as building substantial value for our shareholders. The funding realised through the monetisation of specific royalty rights enables us to accelerate AT278’s clinical development and extends our cash runway to 1H 2027 without diluting our shareholders.” Co-Development Agreement To preserve long-term value within Arecor, the Company has pursued a strategic co-development partnership with an insulin pump innovator. Sequel’s advanced AID technology aligns with Arecor’s commitment to transformative drug delivery solutions. Its twiist™ AID System’s iiSure™ technology leverages acoustic sensing to precisely measure each insulin dose, delivering superior dosing accuracy and detecting occlusions up to nine times faster than other automated insulin delivery systems. This high level of precision makes it an ideal complement to AT278’s ultra-concentrated, ultra-rapid insulin product. Under the terms of the agreement, Arecor and Sequel will co-fund all trial-enabling development activities for the AT278-AID System development programme to achieve Phase 2 trial-ready status. Each company will commit up to $1.3 million to accelerate and fund all Phase 2 clinical trial-enabling development work. This will include regulatory interactions and filings with the US Food and Drug Administration (FDA), clinical trial batch manufacturing and AID System compatibility work. Work will commence immediately and is expected to be completed during 1H 2026, culminating in the filing of an IND (Investigational New Drug). If approved, the programme would be ready to enter a pivotal Phase 2 clinical study during 2H 2026. Longer term, both companies have confirmed their strategic intent to enter a broader, co-development and commercialisation partnership. This would enable the further development and future commercialisation of AT278 in a next generation AID system, serving a key unmet patient need in a high value market. Sarah Howell, CEO of Arecor Therapeutics added: “Sequel has expertise in the development and commercialisation of AID Systems, exemplified by the recent launch of the innovative twiist™ AID System. The pairing of AT278 - the only ultra-concentrated (500U/mL), ultra-rapid insulin in development - with the twiist™ AID system, enables longer wear, even for those people with diabetes (PwD) who require high daily doses of insulin, as well as future miniaturisation opportunities. This combination will unlock powerful benefits for more PwD and provide more choice in how they manage their diabetes. “We are proud to be bringing devices and therapeutics together in a collaboration which addresses a real unmet need in a high value market, helping people with diabetes better manage their blood glucose whilst significantly lowering the daily burden of disease management.” Alan Lotvin, CEO of Sequel Med Tech commented: “We take a comprehensive approach to diabetes management, exploring every opportunity to improve systems that make life easier for people living with diabetes. Our collaboration with Arecor presents a unique opportunity to deliver a truly next-generation solution by integrating our twiist™ AID system - powered by precision iiSure™ technology - with Arecor’s AT278, the only highly concentrated ultra-rapid acting insulin. iiSure™ technology enables twiist™ to be the first system that directly measures the volume of insulin delivered with each microdose and includes 4 checkpoints along the way to help ensure accurate delivery -something no other AID system can do. This precision is especially critical when working with highly concentrated insulin. Together, this combination has the potential to expand the benefits of AID to all individuals on intensive insulin therapy and provide additional options for PwD, helping them achieve tighter glucose control and improved outcomes.” Market Opportunity This partnership, including commercialisation outside the US, presents significant growth potential for Arecor. The Company estimates the total addressable US insulin revenue market opportunity for AT278 is very attractive at c.$2.9 billion with additional upside through commercialisation in Europe and other territories. This is driven by two high unmet-need market segments: 1) People with diabetes who require high daily insulin doses and prefer pumps yet currently lack a suitable pump option and 2) People with diabetes seeking the convenience of an extended-wear device with insulin capacity for 7+ days. In the Arecor management’s opinion, AT278 has the potential to be the only insulin that can enable and catalyse the next generation of longer wear and miniaturised AID systems, simplifying care, reducing care burden and broadening access to people living with Type 1 or Type 2 diabetes. Arecor’s strategic priority has been to pursue high-value R&D opportunities that have the potential to generate significant value for shareholders. Near term, the management anticipates that AT278, the ultra-concentrated, ultra-rapid acting insulin candidate, and the development of a novel oral delivery of peptides platform technology, offer the best opportunities to fulfil this aim. This partnership with Sequel Med Tech is a significant step forward in realising the benefits of AT278 for patients as well building significant value for shareholders. Monetisation of Royalty and Technology Access Fee Streams Arecor has sold the global royalty rights related to AT220, an Arestat®-enhanced biosimilar product marketed by a global pharmaceutical company, and all potential milestone and technology access fees related to AT292 (licensed to Inhibrx, now Sanofi’s Efdoralprin alfa) (the “Royalty Financing Agreement”) to Ligand. Under the terms of the agreement, Ligand will pay Arecor up to $11.0 million (£8.2 million). This includes a $7.0 million upfront cash payment and an additional $4.0 million, which will be payable upon the achievement of certain commercial milestones related to AT220 and AT292, of which $1.0 million is expected to be received during 2026. As part of the transaction, Ligand will receive warrants over 1,002,739 ordinary shares of 1 pence each in the Company (“Ordinary Shares”) which will be fully paid and will rank pari passu in all respects with the existing Ordinary Shares of the Company. The exercise price for the warrants will be 67.39 pence, being the 30-day volume-weighted average price at the date of the agreement. The warrants are exercisable over 10 years. Arecor’s strategic priority has been to pursue high-value R&D opportunities that have the potential to generate significant value for shareholders. Near term, the management anticipates that AT278, the ultra-concentrated, ultra-rapid acting insulin candidate, and the development of a novel oral delivery of peptides platform technology, offer the best opportunities to fulfil this aim. The royalty financing agreement provides immediate, non-dilutive capital, allowing the initiation of AT278 Phase 2-enabling activities without delay, and strengthens Arecor’s balance sheet by extending the cash runway to 1H 2027. Sarah Howell, CEO of Arecor said: “The royalty financing agreement with Ligand is also an important step forward. This financing extends our cash runway to 1H 2027, strengthening the balance sheet for future potential partnering discussions.” Todd Davis, CEO of Ligand said: "We are excited to partner with Arecor on this compelling opportunity to invest in two partnered assets with significant commercial potential. This unique investment exemplifies the types of deals our team aims to pursue, focusing on highly differentiated, de-risked assets that are marketed by strong partners." -ENDS- For more information, please contact: Arecor Therapeutics plc Dr Sarah Howell, Chief Executive Officer David Ellam, Chief Financial Officer+44 (0) 1223 426060info@arecor.comSinger Capital Markets Advisory LLP (NOMAD and Broker) +44 (0) 20 7496 3000Phil Davies, Sam Butcher Vigo Consulting Melanie Toyne-Sewell, Rozi Morris+44 (0) 20 7390 0230arecor@vigoconsulting.com Notes to Editors About Arecor Arecor Therapeutics plc is a clinical stage biopharmaceutical company focused on drug development and delivery in diabetes and other cardiometabolic diseases. The Company is applying its proprietary technology platform, Arestat®, to develop a portfolio of proprietary products, as well as working with leading pharmaceutical and biotechnology companies to deliver enhanced therapeutic products. Its lead product is AT278, the only ultra-concentrated (500U/mL) ultra-rapid acting insulin which is now being co-developed with Sequel Med Tech, a company developing state-of-the art insulin delivery technologies. Arecor is also developing a novel oral delivery platform for peptides (e.g. GLP-1 receptor agonists) targeting the obesity and diabetes markets. The Company is listed on AIM (AIM: AREC) and is based in Cambridge, UK. For further details please see www.arecor.com About AT278 AT278 is a novel proprietary formulation of an existing insulin, designed to accelerate the absorption of insulin post injection even at very high concentrations (500U/mL). With its best-in-class profile, it has the potential to disrupt the market for insulin treatment as the first concentrated, yet very rapid acting insulin for the growing population of people with diabetes with high daily insulin needs as well as to act as a critical enabler in the development of next-generation, miniaturised longer wear automated insulin delivery (AID) systems. About Sequel Med Tech Headquartered in Manchester, New Hampshire, US, Sequel is developing the next generation of transformative drug-delivery advancements. Sequel’s approach is to look at diabetes management holistically to advance systems that make living with diabetes simpler and easier for all. Sequel was co-founded by visionary Dean Kamen, serial entrepreneur Pablo Legorreta, seasoned medical device executive Bill Doyle and healthcare leader Alan Lotvin, MD. Sequel’s focus is to bring the latest developments in science and technology to the marketplace, helping drive more accessible drug delivery. For more information, please visit www.sequelmedtech.com. About AT220 Under a license agreement entered into in 2015, Arecor developed a novel and differentiated, Arestat®-enhanced formulation of its global pharmaceutical company partner's undisclosed product, AT220. The product was first commercialised by Arecor’s partner in November 2023, generating royalties for Arecor under a worldwide license agreement. About AT292 AT292 is an Arestat®-enhanced, optimised recombinant human AAT-Fc fusion protein, for the treatment of patients with emphysema due to alpha-1 antitrypsin deficiency, developed by Arecor under a license agreement entered into by Arecor and Inhibrx in 2020. In 2024 Sanofi acquired Inhibrx's assets and liabilities associated with AT292, now “SAR447537”. A registration-enabling clinical trial of SAR447537 is underway.

Arecor Therapeutics plc(“Arecor” or “the Company”) AT278 ULTRA-CONCENTRATED ULTRA-RAPID ACTING INSULIN DEMONSTRATES SUPERIORITY IN PHASE I CLINICAL TRIAL IN OVERWEIGHT AND OBESE PEOPLE WITH TYPE 2 DIABETES AT278 demonstrates significantly accelerated PK/PD profile compared to NovoRapid® and Humulin® R U-500 in people with Type 2 Diabetes and high BMIConfirms previous trial results in people with Type 1 diabetes, demonstrating AT278 can maintain fast and superior onset of action and glucose lowering profile irrespective of diabetes type and BMIEnables delivery of a highly concentrated, low volume injection, offering more effective mealtime glucose control to meet growing unmet need in patients requiring high daily doses of insulin Creates potential to be the first, and only, ultra-concentrated (500 U/mL) ultra-rapid insulin product enabling miniaturisation of next-generation insulin pumpsCompany will host a CEO and key opinion leader webinar to discuss the results on Tuesday 21 May at 14.30 BST Cambridge, UK, 20 May 2024. Arecor Therapeutics plc (AIM: AREC), the biopharmaceutical group advancing today’s therapies to enable healthier lives, today announces that its ultra-concentrated, ultra-rapid acting insulin candidate, AT278, met all primary and secondary endpoints, and also demonstrated superiority to NovoRapid® and Humulin® R U-500, in a Phase I clinical trial in Type 2 diabetics with a high body mass index (BMI). AT278 (500 U/mL) is an ultra-concentrated, ultra-rapid acting, novel formulation of insulin that accelerates the absorption of insulin post injection, even when delivered at a high concentration, and hence a lower injection volume. With no concentrated (>200 U/mL), rapid acting insulins on the market, AT278 has potential to be the first, and only, insulin available to the growing number of patients with high daily insulin requirements. Sarah Howell, Chief Executive Officer of Arecor, said: "We are delighted with the clinical results from this second Phase I study, demonstrating AT278’s superiority over NovoRapid® and Humulin® R U-500 in Type 2 diabetics with a high BMI. They further add to the positive results from our previous clinical study in Type 1 diabetic patients, where superiority was also demonstrated. This is a significant step in AT278’s development and extends our confidence in its clear potential to provide a superior insulin treatment option that lowers burden and improves outcomes for people living with diabetes who require high daily doses of insulin. Such patients make up a large segment of the target market. In addition, as the only concentrated, yet very rapid acting, insulin in development, AT278 has the capability to disrupt the market by enabling the next generation of truly miniaturised, longer-wear insulin pumps, a key focus for patients, physicians and the industry.” Many Type 2 diabetics with a high BMI are currently not well controlled, and improved treatments options such as AT278 are needed to reduce patient burden through fewer injections per day, reduced injection volumes and dosing flexibility around mealtimes. This lowering of burden for patients improves treatment adherence and, allied with AT278’s superior efficacy, should improve both blood glucose control and outcomes. In addition, a truly ultra-rapid, ultra-concentrated insulin is a critical step towards next-generation miniaturised and long-wearing insulin pumps, which are predicted to transform future diabetes management. Professor Thomas Pieber, Principal Investigator for the ARE-278-104 clinical trial, said: “These results are highly significant, AT278 has clearly demonstrated faster insulin absorption with an accelerated Pharmacokinetic (PK) and Pharmacodynamic (PD) profile compared to the lower concentration standard insulin aspart (NovoRapid®). The PK/PD profile of AT278 (500 U/mL) was also greatly accelerated compared to Humulin® R U-500 (500 U/mL). Together with its superior profile in the earlier Phase I clinical study in Type 1 diabetic patients1 AT278 has demonstrated its ability to maintain a fast and superior onset of action and glucose lowering profile irrespective of diabetes type and BMI. This makes AT278 completely unique in the competitive field of insulin analogues. Not only does it have the potential to significantly improve post-prandial glucose control whilst lowering burden for anybody with diabetes who has a high daily insulin need, it can act as a catalyst in the development of miniaturised insulin delivery systems, where the size of existing devices is a significant barrier to use for many patients.” In the double-blind, randomised, two-way crossover study, the pharmacokinetic (PK)/pharmacodynamic (PD) and safety profiles of a single subcutaneous (SC) dose of 0.5 U/kg AT278 (500 U/mL) were compared with those of a single SC dose of 0.5 U/kg NovoRapid® (100 U/mL), a currently available gold standard, rapid acting insulin treatment, in 39 participants with Type 2 diabetes within a BMI range of 25 and 39 kg/m2, in a euglycemic clamp setting. The PK/PD profile of 0.5 U/kg AT278 (500 U/mL) was also compared to a single SC dose of 0.5U/kg Humulin® R U-500 (500 U/mL) in an open label manner. The trial met the primary endpoint of non-inferiority with respect to glucose lowering actions compared with NovoRapid®AT278 (500 U/mL) demonstrated a significantly accelerated (superior) early PK/PD profile compared to NovoRapid® (100 U/mL), despite a 5-fold increase in concentrationAT278 (500 U/mL) demonstrated a significantly accelerated (superior) PK/PD profile compared to Humulin® R U-500 (500 U/mL), the only other insulin available at a concentration of 500 U/mL No safety signals were detected With around 537m people living with diabetes worldwide, there are growing numbers of people who require insulin to manage their blood glucose and, for many, their diabetes is still poorly controlled. There is a growing need for highly concentrated, much faster, and more physiological insulins to effectively manage diabetes. In the US alone, nearly 10% of insulin scripts written in 2022 were for products with a concentration of >100 U/mL2. Furthermore, despite the improvements in outcomes among people with diabetes who use insulin pumps and automated delivery systems, they are still only used by less than 40% of people with Type 1 diabetes and less than 10% of people with Type 2 diabetes in the US3. The size and short duration of wear of existing insulin pumps remains a significant barrier to use. AT278 has the potential to be the only highly concentrated, ultra-rapid acting insulin to enable the next generation of miniaturised, longer wear insulin pumps. The insulin pump market is valued at circa $5.5bn market today4, with a significant opportunity for substantial growth in this market by expanding use across the Type 1 and Type 2 patient population that can be further enabled by AT278 and a next generation insulin pump. A full analysis of the trial data is now underway to enable the Company to determine and pursue a strategy for AT278 that maximises value for shareholders and patients. Detailed data from the trial will be submitted for publication and presentation at a future international diabetes conference. AT278 clinical results CEO and KOL webinar - Tuesday 21 MayDr Sarah Howell, Chief Executive Officer, and Professor Thomas Pieber, Principal Investigator for the ARE-278-104 clinical trial and Professor of Medicine, Head of the Division of Endocrinology and Metabolism and Chairman of the Department of Internal Medicine at Medical University of Graz, Austria will host a CEO and key opinion leader webinar to discuss the clinical results on Tuesday 21 May at 14.30 BST. To register to join the live webcast click here and to register for the conference line to ask questions click here. Please contact ICR Consilium for details on arecor@consilium-comms.com. This announcement contains inside information for the purposes of the retained UK version of the EU Market Abuse Regulation (EU) 596/2014 ("UK MAR"). -ENDS- References Pharmacokinetics and Pharmacodynamics of a Novel U500 Insulin Aspart Formulation: A Randomized, Double-Blind, Crossover Study in People With Type 1 Diabetes Care 2023;46(4):757–764: https://doi.org/10.2337/dc22-10542022 reports from Symphony. Retrieved October 2023Seagrove Partners Diabetes Bluebook 2022Insulin pump company annual reports and Company estimates For more information, please contact: Arecor Therapeutics plcwww.arecor.comDr Sarah Howell, Chief Executive OfficerTel: +44 (0) 1223 426060Email: info@arecor.com Susan Lowther, Chief Financial OfficerTel: +44 (0) 1223 426060Email: info@arecor.com Panmure Gordon (UK) Limited (NOMAD and Broker) Freddy Crossley, Emma Earl (Corporate Finance)Rupert Dearden (Corporate Broking)Tel: +44 (0) 20 7886 2500 WG Partners LLP (Financial Advisor) Nigel Barnes, Satheesh NadarajahDavid Wilson, Claes SpangTel: +44 (0)203 705 9321 ICR Consilium Chris Gardner, David Daley, Lindsey NevilleTel: +44 (0) 20 3709 5700Email: arecor@consilium-comms.com Notes to Editors About Arecor Arecor Therapeutics plc is a globally focused biopharmaceutical company transforming patient care by bringing innovative medicines to market through the enhancement of existing therapeutic products. By applying our innovative proprietary technology platform, Arestat™, we are developing an internal portfolio of proprietary products in diabetes and other indications, as well as working with leading pharmaceutical and biotechnology companies to deliver therapeutic products. The Arestat™ platform is supported by an extensive patent portfolio. For further details please see our website, www.arecor.com