• Stefan Ries joins as CSO, bringing more than two decades of drug development experience in the pharmaceutical industry complemented by a background in venture capital

• Elena Ardini joins as VP of R&D with over 20 years of experience in oncology drug development and a proven track record of advancing a therapy to market approval

Milan, Italy, September 4, 2025 – Sibylla Biotech today announced the appointment of Stefan Ries, PhD, as Chief Scientific Officer and Elena Ardini, MSc as Vice President of Research and Development. Dr. Ries and Ms. Ardini will apply their deep knowledge of the scientific and commercial aspects of drug discovery development to advance the company’s pipeline toward clinical evaluation. These additions to the leadership team support Sibylla’s growth and the evolution of its Pharmacological Protein Inactivation by Folding Intermediates Targeting (PPI-FIT) technology.

“Elena and Stefan will strengthen our scientific leadership team as we advance our pipeline of folding interference small molecules and prepare to enter the clinic. Their unwavering commitment to advancing innovative therapeutics, sharp business acumen and experience in supporting corporate strategy will be instrumental as we continue leveraging our technology to address difficult targets across multiple disease areas. Their eagerness to embrace new challenges and their dedication to driving the success of our PPI-FIT technology align seamlessly with Sibylla’s corporate culture, making them an exceptional addition to our organization,” said Lidia Pieri, PhD, MBA, Co-Founder and Chief Executive Officer of Sibylla Biotech.

Dr. Ries is a scientific executive with over 20 years of drug discovery and development experience and an oncology focus. As CSO of DISCO Pharmaceuticals, he spearheaded the company’s R&D strategy and scalable drug discovery activities. Prior to this, Stefan was a Venture Partner at Versant Ventures, a global venture capital firm focused on healthcare and biotechnology, with an emphasis on novel therapeutics. Dr. Ries also completed 16 years at Hoffmann-La Roche, culminating in his role as Vice President, External Innovation, Oncology where he oversaw scientific due diligence to evaluate potential assets and technologies for collaboration, licensing and acquisition. Dr. Ries holds a PhD in Biochemistry from the University of Regensburg, Germany and completed a postdoctoral fellowship in the lab of Professor Frank McCormick at the NCI-designated Cancer Center of the University of California, San Francisco. He is a member of the American Association for Cancer Research.

“Sibylla is pioneering a novel approach to targeted protein degradation that has the potential to unlock previously undruggable targets in high-need indications,” added Stefan Ries, PhD, Chief Scientific Officer of Sibylla Biotech. “Joining the company at this pivotal moment, as it nears the clinic, is an exciting opportunity to help shape its next phase of growth and guide the strategic progression of its pipeline. I am eager to work together with Elena and the team to help identify the right targets and indications to drive meaningful scientific progress.”

Ms. Ardini is a leader in the oncology field with over 20 years of experience in drug discovery, specializing in the identification and development of innovative oncological drugs. Since joining in 2000, she has held various scientific and managerial positions at Nerviano Medical Sciences, a company focused on developing novel small molecule oncology drugs. Most recently she served as Asset Leader and Head of Early Development Strategy and Clinical Project Leader. Notably, Ms. Ardini spearheaded the pre-clinical development and strategic decisions for the clinical development of entrectinib/Rozlytr®, a registered targeted cancer therapy used to treat solid tumors. She holds a master’s degree in Biological Sciences from the University of Milano, Italy.

About Sibylla Biotech

Sibylla is transforming drug discovery by targeting protein folding intermediates, unlocking a new druggable dimension within the pharmacological landscape. Unlike most drugs that act on native proteins, Sibylla's approach intervenes earlier in the process, targeting proteins before they become undruggable.

Through its proprietary technology platform, PPI-FIT, Sibylla predicts and targets intermediate steps in the protein folding process. The company’s small molecule drug candidates disrupt the folding process, resulting in targeted protein degradation via the physiological pathways.

Sibylla is advancing an innovative pipeline of treatments for diseases with significant unmet medical needs across multiple therapeutic areas, driven by its mission to deliver protein folding interference therapeutics to patients worldwide.

About Vi Partners

Vi Partners is the longest-established venture capital firm in Switzerland. For over 20 years, Vi Partners has supported innovative technology and healthcare companies, investing over CHF 350 million in 72 startups. Vi Partners-managed funds are backed by some of Switzerland’s most prominent companies and institutions, including ETH Zurich, ABB, Bühler, Credit Suisse, Hilti, McKinsey, Nestlé, Schindler, Sulzer, Suva, and ZKB, as well as the European Investment Fund and many other institutional investors.