FAN1

Newly established SAB of prominent geneticists, biologists and Huntington’s disease specialists’ marks pivotal step in accelerating progress of lead programme HRN001 Cambridge, UK, May 30, 2024: Harness Therapeutics, a biotechnology company focused on protein upregulation to develop next generation therapeutics for neurodegenerative diseases, today announces the formation of its new SAB, consisting of renowned leaders in the genetics, biology, and clinical development of Huntington’s disease (HD) and other important neurodegenerative disorders: Dr. Irina Antonijevic – CMO EveryONE MedicinesProf. Roger Barker – University of CambridgeProf. Jim Gusella – MGH, HarvardProf. Jeff Long – University of IowaDr. Eric Marcusson – Independent ConsultantDr. Tom Massey – University of CardiffDr. Ralf Reilmann – George Huntington InstituteDr. Jennifer Sims – Independent Consultant The SAB members will support Harness Therapeutics’ research and development activities, offering invaluable scientific and clinical guidance as the Company progresses its lead HD programme HRN001 through CTA-enabling studies, scheduled to begin in 2025, and beyond this towards clinical development. HRN001 is designed to increase levels of FAN1 nuclease, the strongest genetic modifier of HD onset. Increases in FAN1 have been shown to slow down the expansion of CAG ‘triplets’ (somatic instability), which is now understood to be the key driver of HD progression. Harness is leading efforts to exploit this important target through its deep understanding of the relevant translational biology and by utilising its platform for physiological upregulation, based on optimising protein translation from endogenous mRNA. By means of this controlled increase in target protein expression, Harness hopes to develop HRN001 as the first truly disease-modifying therapy for HD. With input from the SAB, Harness will also continue to build its pipeline of neurodegenerative disease assets. The Company has now introduced a second programme aiming to target a specific process to reduce the formation of TPD-43 aggregates which are believed to drive some of the most common neurodegenerative diseases including Alzheimer’s disease and amyotrophic lateral sclerosis (ALS). Dr Jan Thirkettle, CEO of Harness Therapeutics, commented “I am thrilled to announce the establishment of Harness’ Scientific Advisory Board. These highly accomplished scientists and clinicians bring a wealth of knowledge and experience across all aspects of Huntington's disease research and treatment as well as the broader neurodegenerative disease landscape. Their expertise will not only help us accelerate the development of a potentially transformative treatment for HD patients but will also bolster our efforts to explore promising avenues of research for other neurodegenerative disorders that may benefit from our approach to controlled physiological upregulation, including Alzheimer’s disease, Parkinson’s disease and ALS”. Dr. Irina Antonijevic, chair of the SAB added, “Recent advancements in the Huntington’s disease field have put a spotlight on the importance of FAN1 as a target for the development of novel therapies for this disease which, if successfully exploited, could provide significant benefits to patients. Harness is leading this charge with HRN001, which is designed to selectively increase FAN1 nuclease levels in a controlled manner to reduce the triplet expansion that drives Huntington’s disease progression. This is a highly promising approach and I and the SAB look forward to helping the company progress this programme for the many people with HD in need as well as advancing the platform to enable development of disease-modifying therapies for other neurodegenerative disorders” *** About Harness Therapeutics Harness Therapeutics is a biotechnology company focused on the development of next-generation therapeutics for the treatment of neurodegenerative diseases, with a lead programme in Huntington’s disease targeting FAN1 to limit somatic expansion. Focussing on neurodegeneration targets with strong biology and genetic validation, Harness Therapeutics utilises its deep understanding of RNA biology and post-transcriptional regulation to enable drugging of targets with oligonucleotide-based drugs to achieve controlled increases in protein expression. Harness Therapeutics has assembled a world-class team focused on the mission of building the most efficient platform for controlled upregulation of CNS targets that underpin neurodegenerative disease. This includes extensive RNA biology and bioinformatics expertise, specialist analytics capabilities and unique neuronal cell models. Harness Therapeutics’ unique platform generates multiple orthogonal upregulation strategies that are tested in highly translatable in vitro cell models to identify constructs capable of increasing endogenous protein translation. This specific and controlled approach to increasing target proteins provides a mechanism to drug targets that are not addressable using gene therapy or other modalities. Harness Therapeutics is based in Cambridge, UK, and was originally established by leading life science investors Takeda Ventures and SV Health Investors’ Dementia Discovery Fund in 2020. Harness Therapeutic’s current investor base now also includes Epidarex Capital. For more information, please visit www.harnesstx.com/ and follow us on LinkedIn. CONTACTS:Harness TherapeuticsDr Jan Thirkettle, CEOinfo@Harnesstx.com MEDiSTRAVA Sylvie Berrebi, Frazer HallHarnesstx@medistrava.com

Harness, formerly operating as Transine, broadens its approach to physiological protein upregulation through post-transcriptional modulation of protein synthesis Refined focus on neurodegenerative disease targets Proceeds to be used to advance lead programme targeting FAN1 nuclease in Huntington’s Disease towards the clinic Cambridge, UK, 28thNovember 2023: Harness Therapeutics (‘Harness’, previously Transine Therapeutics), a biotechnology company focused on physiological protein upregulation to develop next generation therapeutics for the treatment of neurodegenerative diseases, announces that it has successfully raised an additional £4 million in funding from its existing investors, bringing the total invested to £17.6 million. Proceeds will be used to advance Harness’ lead Huntington’s Disease (HD) programme targeting FAN1 nuclease and pursue target discovery and validation activities in other neurodegenerative disease pathways. “We have made great strides in our earlywork on post-transcriptional regulation of protein expression, and I am eager to bring the unique capabilities and target insights we have acquired into action with our refined focus on neurodegeneration. There is a pressing need for new approaches in neurodegeneration where compelling targetscould be unlocked by controlled upregulation,” said Dr Jan Thirkettle, CEO of Harness Therapeutics. “This further investment puts us in a strong position to address multiple neurodegenerative disease pathways, with an initial focus on progressing our lead FAN1 nuclease programme into clinical development for Huntington’s Disease. I strongly believe that by pursuingphysiological protein upregulation of targets with strong biology and genetic validation we can deliver new medicines that currently cannot be discovered through other methods.” Harness Therapeutics was originally established as Transine Therapeutics in 2020 by leading life science investors Takeda Ventures and The Dementia Discovery Fund (DDF), with Epidarex Capital joining as an investor in 2022. Harness initially focussed on advancing its IncRNA “SINEUP” platform for upregulation of protein expression and the investment committed through this period has enabled Harness to build deep RNA biology alongside bespoke analytical capabilities. From this work, the company has gained unique insights into the regulation of therapeutic targets and broadened its oligonucleotide based toolset for physiological protein upregulation. Miles Gerson, Executive Investment Director & Partner at Takeda Ventures commented, “We are very excited to extend further investment in support of Harness’ commitment to pursuing differentiated therapies for an area with considerable unmet need. We believe that the Harness team has developed an exceptional RNA Biology platform that is insightfully designed to overcome the limitations of other platforms, enablingnovelapproaches to address the underlying drivers of neurodegenerative diseases.” Christian Jung, Partner at SV Health Investors, investing out of DDF and Chairman of Harness’ Board, said, “We are delighted to have been an early investor in Harness and are excited to see its unique target-focussed approach now being focussed on neurodegenerative diseases. We believe the technology holds the potential to bring forward important new medicines that can change the lives of neurodegenerative disease patients who currently have few or no effective treatment options available to them.” *** About Harness Therapeutics Harness Therapeutics is a biotechnology company focused on the development of next generation therapeutics for the treatment of neurodegenerative diseases, with a lead programme in Huntington’s Disease. Focussing on neurodegeneration targets with strong biology and genetic validation, Harness Therapeutics utilises its deep understanding of RNA biology and post-transcriptional regulation to enable drugging with oligonucleotide based drugs to upregulate protein expression. Harness Therapeutics has assembled a world-class team focused on the mission of building the most efficient physiological protein upregulation platform. This includes extensive RNA biology and bioinformatics expertise, specialist analytics capabilities and neurological cell models. Harness Therapeutics’ unique target-centric approach generates multiple orthogonal upregulation strategies combined with a detailed understanding of target biology to develop new medicines that can treat the underlying causes of neurodegenerative diseases. Harness Therapeutics is based in Cambridge, UK, and is backed by leading life science investors – Takeda Ventures, The Dementia Discovery Fund and Epidarex Capital. For more information, please visit and follow us on LinkedIn. CONTACTS Harness Therapeutics Dr Jan Thirkettle, CEO info@Harnesstx.com MEDiSTRAVA Consulting Sylvie Berrebi, Frazer Hall Harnesstx@medistrava.com