Sonlicromanol

Khondrion receives FDA clearance of IND application for pivotal Phase 3 clinical trial of sonlicromanol for the treatment of primary mitochondrial disease 52-week Phase 3 trial to investigate potential of novel, brain-penetrant redox-modulator with anti-inflammatory properties, in adult patients with most common genetic defect causing primary mitochondrial disease, m.3243A>GPrimary endpoints focused on most burdensome and frequently occurring effects of disease – chronic fatigue and muscle weakness – supported by significant and clinically relevant patient benefits achieved by sonlicromanol in its integrated Phase 2b program NIJMEGEN, the Netherlands – 14 November 2024: Khondrion, a clinical stage biopharmaceutical company discovering and developing therapies targeting primary mitochondrial disease (PMD), today announced that it has received clearance from the U.S. Food and Drug Administration (FDA) for its Investigational New Drug (IND) application for sonlicromanol. The IND supports the initiation of a pivotal Phase 3 trial in adult patients with PMD due to the m.3243A>G mutation, the most common genetic defect causing PMD. The company expects to initiate the trial in 2025. Sonlicromanol, Khondrion’s lead proprietary drug candidate, is a potentially disease-modifying first-in-class, brain-penetrant redox-modulator with anti-inflammatory properties, that targets key metabolic and inflammatory pathways underlying PMD. The Company’s multicenter Phase 2b program, recently published in the scientific journal Brain, highlighted strong patient benefits from sonlicromanol in multiple outcome measures. That program’s 52-week extension study, which continued to treat some patients out to 78 weeks, demonstrated durable improvements among patients receiving sonlicromanol in several relevant domains, including chronic fatigue and muscle weakness, two of the most burdensome symptoms of PMD as described by patients. The drug candidate’s potential to treat these aspects of disease will be further investigated in the upcoming Phase 3 trial. The 52-week double-blind, randomized, placebo-controlled, multi-center, parallel-group Phase 3 trial is expected to enroll 150 adult patients with a genetically confirmed mitochondrial DNA tRNALeu(UUR) m.3243A>G variant. For this study, Khondrion has selected the Neuro-QoL Fatigue short form questionnaire and the Five Times Sit-to-Stand test as its two independent primary endpoints. These outcome measures, assessing patients’ most burdensome and frequent effects of disease (chronic fatigue and muscle weakness), have encouragingly shown clinically meaningful and statistically significant (p-value of 0.004 and 0.0161, respectively) results in the 52-week open-label extension part of the Phase 2b program. Further details of the Phase 3 trial’s design can be found on ClinicalTrials.gov here. Prof. Dr. Jan Smeitink, Chief Executive Officer at Khondrion, said: “The FDA’s clearance of our IND application for a pivotal Phase 3 trial marks another important milestone for Khondrion’s development of sonlicromanol, a disease-modifying therapy for primary mitochondrial disease that is so desperately needed by PMD patients. We look forward to sharing progress of our clinical program including its expected initiation next year.” Sonlicromanol: one of the most advanced drug candidates in development for PMDSonlicromanol has been investigated in four clinical trials, three in adult PMD patients with m.3243A>G, as well as in the first wave of a six-month Phase 2 study in children with genetically confirmed PMD suffering from motor symptoms. Encouragingly, seven patients in the Netherlands, who elected to participate in a named patient program following completion of the Phase 2b open label extension study out to 78 weeks, have been receiving sonlicromanol for more than two and a half years, thus confirming the drug’s favorable safety profile. Khondrion is initially focusing the development of sonlicromanol on PMD patients with the m.3243A>G variant, which is the most common genetic defect causing multi-systemic PMD and has an estimated prevalence of 4.4:100,000. There are currently no approved therapies for PMD associated with the m.3243A>G variant. The Company’s longer-term objective is to make sonlicromanol widely available for the broader PMD patient community. PMDs are the most prevalent inherited neurometabolic disorders, estimated to affect at least 1 in 4,300 which translates into approximately 65,000 people in the US alone. Khondrion’s wholly-owned, proprietary drug candidate has received orphan drug designation in the US and Europe and has also been granted a rare pediatric disease designation. – ENDS – Notes to editors About KhondrionKhondrion is a clinical stage biopharmaceutical company developing therapies for patients with primary mitochondrial disease (PMD). The company’s lead asset, sonlicromanol, is a potentially first-in-class, brain-penetrant redox-modulator with anti-inflammatory properties, that targets key metabolic and inflammatory pathways underlying PMD. One of the most advanced, disease-modifying drug candidates for mitochondrial disease in development, sonlicromanol has been tested in three clinical trials in patients with m.3243A>G PMD, as well as in the first wave of a 6-month Phase 2 study in children with genetically confirmed PMD and who suffer from motor symptoms. Sonlicromanol has been granted orphan drug designations for the treatment of MELAS syndrome (mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes), Leigh disease and patients with maternally inherited diabetes and deafness (MIDD) in Europe, and for all inherited mitochondrial respiratory chain disorders in the U.S. It has also been granted a rare pediatric disease designation in the US for the treatment of MELAS. Sonlicromanol and other compounds from Khondrion’s proprietary library have the potential to be developed for a wide range of diseases and conditions with the aim of benefiting patients whose daily lives are severely impacted by mitochondrial impairment. For more information visit www.khondrion.com. About Primary Mitochondrial DiseaseMitochondrial disease occurs when mitochondria, found within all cells of the human body except erythrocytes, and responsible for producing the energy necessary for cells to function, are defective. This can result in a wide range of serious and debilitating illnesses occurring shortly after birth or later in life. Signs and symptoms of these can include cognitive problems, learning disabilities, blindness, deafness, heart failure, diabetes, fatigue, intolerance to exercise, muscle weakness and gait problems, and stunted growth. Originally referred to as MELAS syndrome (mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes), primary mitochondrial disease associated with the m.3243A>G variant in the mitochondrial genome is now considered to include a spectrum of phenotypes including classic MELAS, MIDD syndrome (maternally inherited diabetes mellitus and deafness), MP (mixed phenotypes) and CPEO (chronic progressive external ophthalmoplegia). Learn more. Forward-looking statementsThis press release may contain certain forward-looking statements regarding, among other things, the results, conduct, progress and timing of the company’s clinical trials and presentation of data from clinical trials for sonlicromanol. Although the company believes its expectations are based on reasonable assumptions, all statements other than statements of historical fact included in this press release about future events are subject to (i) change without notice and (ii) factors beyond the company’s control. These statements may include, without limitation, any statements preceded by, followed by or including words such as “target,” “believe,” “expect,” “aim,” “goal,” “intend,” “may,” “anticipate,” “foreseen,” “estimate,” “plan,” “project,” “will,” “can have,” “likely,” “potential,” “should,” “would,” “could” and other words and terms of similar meaning or the negative thereof. Forward-looking statements are subject to inherent risks and uncertainties beyond the company’s control that could cause the company’s actual results, performance or achievements to be materially different from the expected results, performance or achievements expressed or implied by such forward-looking statements. Except as required by law, the company assumes no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in the forward-looking statements, even if new information becomes available in the future. Contacts: Khondrion BVProf. Dr. Jan Smeitink, CEOE-mail: info@khondrion.comTel: +31-24-7635000www.khondrion.com ICR Healthcare David Daley, Kris LamEmail: khondrion@icrhealthcare.com 1 Excluding data from two subjects whose baseline duration in the 5xSST test was below the envisaged threshold criteria to be used for analysis of the 5xSST test endpoint in the Phase 3 trial

NIJMEGEN, The Netherlands – November 8, 2024: Khondrion, a clinical-stage biopharmaceutical company specializing in mitochondrial disease therapies, and Amsterdam UMC together with Vrije University Amsterdam have announced to initiate a Phase 2 clinical trial to test its leading drug candidate, sonlicromanol, in patients struggling with persistent post-COVID symptoms. These longlasting effects—such as chronic fatigue, post-exertional malaise, brain fog, and symptoms worsened by physical or mental activity—continue to impact millions of lives globally. This trial is funded by the Dutch Organisation for knowledge and innovation in health, healthcare and well-being (ZonMw; project number 11080022420008), with patient recruitment set to begin by the end of Q1 2025. Understanding the Challenge of Post-COVID Symptoms‍ Even after recovering from the initial infection, many patients experience enduring health issues collectively known as “post-COVID” or “long COVID.” Common symptoms include severe fatigue, cognitive impairment (brain fog), and post-exertional malaise—a significant worsening of symptoms following exertion. These challenges make everyday tasks like working, exercising, and socializing difficult, heavily affecting quality of life for those affected. Recent research points to mitochondrial dysfunction—the impaired ability of cells to produce energy—as a potential root cause of these ongoing symptoms. A Promising New Approach: The “Sonlicromanol in Post-COVID” Study The Phase 2 study, officially titled “Sonlicromanol in Post-COVID,” will employ a double-blind, placebo-controlled design, the most rigorous standard for clinical trials. It aims to evaluate whether sonlicromanol can provide relief by mitigating the cytotoxic effects of mitochondrial dysfunction, the suspected underlying driver of post-COVID symptoms. The trial will give Khondrion and Amsterdam UMC valuable early insights into the drug’s potential effectiveness for this new application. Prof. Dr. Jan Smeitink, CEO of Khondrion, highlighted the versatility of the drug: “Sonlicromanol, which has advanced to Phase 3 development for primary mitochondrial diseases, shows promise as a ‘pipeline-in-a-product’ due to its unique triple mode of action that combats the pathomechanisms that are common to many forms of mitochondrial dysfunction. We’re excited to explore how sonlicromanol may help patients that suffer from post-COVID, treating it as a secondary mitochondrial disease.” Sonlicromanol: A Breakthrough in Mitochondrial Dysfunction Therapy Sonlicromanol is a first-in-class drug is a first-in-class, brain-penetrant redox modulator with and inflammatory properties that mitigates the detrimental effects caused by mitochondrial dysfunction. By mitigating the effects of mitochondrial dysfunction, sonlicromanol offers a novel therapeutic approach for the most challenging symptoms of post-COVID. The newly secured ZonMW funding for this trial represents a critical opportunity to test its efficacy, with potential benefits for thousands of patients in the Netherlands and millions worldwide. A Strategic Move for Investors and Public Health Advocates This Phase 2 trial marks an important milestone in addressing the global challenge of post-COVID. With the potential to open new markets for sonlicromanol and expand its therapeutic applications, the study represents a strategic investment opportunity in the evolving field of mitochondrial medicine. For patients, their families, and healthcare professionals, this research could pave the way toward a more effective treatment for post-COVID conditions and provide renewed hope for a better quality of life.