THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION FOR THE PURPOSES OF ARTICLE 7 OF EU REGULATION 596/2014 AS IT FORMS PART OF DOMESTIC LAW IN THE UNITED KINGDOM BY VIRTUE OF THE EUROPEAN UNION (WITHDRAWAL) ACT 2018. UPON THE PUBLICATION OF THIS ANNOUNCEMENT VIA A REGULATORY INFORMATION SERVICE, THIS INSIDE INFORMATION WILL BE CONSIDERED TO BE IN THE PUBLIC DOMAIN.

Solvonis Therapeutics plc

("Solvonis" or the "Company")

New Analysis Identifies Major AUD Breakthrough: SVN-001 Ahead of Established and Emerging AUD Treatments in Cross-Trial Analysis

Substantial Reductions in Heavy Drinking Days - a Key Outcome Recognised by European Regulators - Strengthen Solvonis' Push Into Europe

·      Ahead of Competitors: SVN-001 ahead of naltrexone (Vivitrol, 25%) and the GLP-1 therapies pemvidutide (35%) and semaglutide (46%) on relative heavy-drinking-day reduction, in indirect, cross-trial comparisons.

·      Major Reduction in Harmful Drinking: 67% fewer heavy drinking days than placebo at weeks 17-20 - a statistically significant result (55% pooled across the full 24-week follow-up).

·      A Fundamentally More Patient-Friendly Dosing Model: A short, defined 4-week course - versus Vivitrol's monthly injections and GLP-1 therapies' ongoing weekly dosing.

·      The Science Behind the Result: Significantly less craving than placebo at three months - an early indicator of why SVN-001 works.

·      Building an International Franchise: SVN-001 is advancing through UK Phase 3 with European expansion planned, while SVN-002 targets the US - addressing an estimated 12.5 million people with severe AUD across the UK and EU4, and 11.3 million with moderate-to-severe AUD in the US¹.

Anthony Tennyson, Chief Executive Officer, commented: "SVN-001 now has both a mechanism and data. It eases the craving and negative thinking that drive relapse - and on the endpoint EMA actually uses, it's ahead of the standard of care and the GLP-1 therapies everyone's watching. That's the foundation for the European expansion we're building. The human and economic cost of AUD is enormous: in England alone, it is estimated to cost over £27bn a year, with £4.9bn of that falling on the NHS². This is a crisis that needs tackling, and we believe SVN-001 can be an integral part of the solution."

LONDON - 29 September 2026 - Solvonis Therapeutics plc (LSE: SVNS), a late clinical-stage biopharmaceutical company developing small-molecule therapeutics for high-burden central nervous system ("CNS") disorders, today announces two new analyses from the Phase 2 KARE trial of SVN-001, its lead treatment for severe Alcohol Use Disorder ("AUD").

In relative terms, SVN-001's results exceed those reported for naltrexone (Vivitrol, 25% in its own registration trial), pemvidutide, a GLP-1 therapy in Phase 2 development for AUD (35%, reported July 2026), and semaglutide, a GLP-1 therapy shown to reduce heavy drinking days by 46% across two randomized trials (the larger restricted to patients with comorbid obesity). These are separate trials in different populations, so the comparison is indirect and doesn't establish comparative efficacy - but the dosing contrast is a genuine structural difference: SVN-001's results held after a short, defined 4-week course, against Vivitrol's monthly injections and GLP-1 therapies' ongoing weekly dosing.

That result comes from a new analysis, "No Heavy Drinking Days and Percentage of Days Abstinent in a Randomized Trial of Adjunctive Ketamine for Alcohol Use Disorder: Secondary Analysis of the KARE Trial" (Morgan & Nutt).

SVN-001 patients had 67% fewer heavy drinking days than placebo at weeks 17-20 of follow-up - more than four months after the last infusion - a statistically significant result on EMA's primary AUD endpoint. Pooled across weeks 17-24, the reduction was 55%, directionally consistent though not significant at conventional thresholds on its own. Days abstinent rose significantly in every window measured. This is the endpoint EU regulators use to evaluate AUD treatments, and forms the evidence base as Solvonis moves into Europe.

A second analysis, "Mechanisms of Anti-Depressant and Anti-Alcohol Effects of Ketamine in Patients with Alcohol Use Disorder" (Mollaahmetoglu et al.), found that ketamine treatment was associated with significant reductions in craving and rumination at three months, adding to an earlier finding that SVN-001 increases patients' ability to feel pleasure - the same psychological pathways already established in ketamine's use for depression. Patients with a family history of AUD showed a stronger response on both measures, a hypothesis-generating signal the ongoing MORE-KARE Phase 3 trial is designed to test directly.

Building an AUD treatment franchise: Solvonis is building on three fronts at once. SVN-001 is recruiting in the 280-participant UK MORE-KARE Phase 3 trial, co-funded with the NIHR (National Institute for Health and Care Research). Together, these analyses are the evidence base for European expansion and SVN-002, Solvonis' esketamine oral thin-film, is advancing toward US Phase 2 following a pre-IND (Investigational new Drug) meeting with the FDA.

Professor David Nutt, Chief Scientific Officer, commented: "It's one thing to show a treatment works. It's another to understand why, and to know how it compares. These analyses give us all three - and the family-history finding starts to tell us who might benefit most, which is exactly what Phase 3 is designed to test."

The fine print: These are new analyses of previously published trial data. The heavy-drinking-day reduction endpoint reflects EMA guidance for reduction-focused AUD trials; FDA's recognised AUD endpoints - abstinence and the percentage of patients with no heavy drinking days - are evaluated separately. The 67% reduction at weeks 17-20 was statistically significant (p=0.018); the 55% pooled reduction across weeks 17-24 was not (p=0.062). Days-abstinent p-values ranged from 0.039 to 0.011. The mechanism analysis is exploratory and was not powered to establish mediation; the family-history finding is hypothesis-generating, from a small sample. Comparisons to naltrexone (Vivitrol), pemvidutide, and semaglutide use separate trials and populations; pemvidutide's figures come from a topline press release, not peer-reviewed data, and its population was restricted to BMI >25 kg/m², unlike KARE's. Semaglutide's reported reduction draws on two peer-reviewed randomized trials; the larger of the two was restricted to patients with comorbid obesity. These comparisons do not establish comparative efficacy. Dosing schedules cited for Vivitrol, pemvidutide, and semaglutide reflect their approved or reported regimens, not a head-to-head trial. KARE trial data was generated by the University of Exeter, led by Professor Celia Morgan, and is used by Solvonis under an existing collaboration arrangement. The Company's website and investor materials are being updated to reflect these analyses; prior published figures used a different measurement approach. The mechanism analysis has been submitted for publication (Mollaahmetoglu et al.). The heavy-drinking-day findings have been submitted to a peer-reviewed journal as a research letter (Morgan & Nutt) and are available as a preprint on medRxiv, pending journal outcome. KARE's heavy-drinking-day threshold differs from current FDA and EMA thresholds. All figures are unadjusted for multiple comparisons and post hoc. SVN-001 and SVN-002 remain investigational and are not approved for use anywhere.

1 UK and EU4 (France, Germany, Italy and Spain) severe-AUD, and US moderate-to-severe AUD, figures are Company-derived epidemiological estimates (WHO Europe prevalence data; Degenhardt et al., Addiction 2019; Eurostat 2024; ONS mid-2024; SAMHSA NSDUH) and are not estimates of treated, treatment-seeking or product-eligible populations.

2 Institute of Alcohol Studies, "£27.4 billion cost of alcohol harm in England every year," May 2024

Enquiries

Solvonis Therapeutics plc
Anthony Tennyson, CEO & Executive Director
[email protected]

Turner Pope Investments (TPI) Limited
Corporate Broker and Sole Bookrunner
Andrew Thacker / Guy McDougall
+44 (0)20 3657 0050

About Solvonis Therapeutics plc

Solvonis Therapeutics plc (LSE: SVNS) is a late clinical-stage biopharmaceutical company developing small-molecule therapeutics for high-burden central nervous system ("CNS") disorders. Headquartered in London and listed on the Main Market of the London Stock Exchange, Solvonis is advancing a differentiated pipeline of repurposed and discovery-stage compounds across addiction and psychiatry.

The Company's lead programmes target Alcohol Use Disorder ("AUD") and Post-Traumatic Stress Disorder ("PTSD"), with additional development and discovery work supporting expansion into further addiction and psychiatric indications, including stimulant use disorder and depressive disorders.

Its lead asset, SVN-001, is currently in Phase 3 for severe AUD in the UK, while SVN-002 is being advanced towards a planned Phase 2b trial in the United States targeting moderate-to-severe AUD. The Company's PTSD discovery programme has identified SVN-114 as a lead compound, emerging from a proprietary compound series designed to modulate key brain-signalling systems associated with emotional processing and social behaviour.

SVN-015 is the Company's proprietary discovery-stage candidate targeting stimulant use disorder. Following encouraging initial cardiac ion-channel and broader off-target screening results, it is advancing into further preclinical evaluation under NIDA's Addiction Treatment Discovery Program.

In parallel, Solvonis is advancing proprietary CNS discovery programmes supported by a dedicated compound library and AI-enabled discovery capabilities to identify new small-molecule modulators of key neurotransmitter systems.

solvonis.com | LinkedIn |X