Biotech Veteran Renato Skerlj to Lead Rhapsogen's Autoimmune Push

CAMBRIDGE, Mass. – January 06, 2026 – Immunology startup Rhapsogen has named Dr. Renato Skerlj, a seasoned biotechnology executive with a track record of steering novel drugs through to FDA approval, as its new Chief Executive Officer. The appointment signals a pivotal moment for the Cambridge-based company, which was launched last year by Catalio Capital Management with the ambitious goal of redefining the treatment paradigm for autoimmune diseases.

Dr. Skerlj takes the helm of a company built on a formidable scientific foundation, co-founded by two of the world's leading immunologists, Prof. Jeffrey Ravetch of Rockefeller University and Prof. Eric Sundberg of Emory University. His appointment brings a crucial layer of drug development expertise to Rhapsogen's deep scientific credibility, positioning the young company to accelerate its mission.

“I am very excited by what we are building at Rhapsogen and look forward to working with our world-class team of immunology experts to deliver the solutions that autoimmune patients need and deserve,” said Dr. Skerlj in a statement.

A Proven Leader in Drug Development

Dr. Skerlj is not a typical first-time biotech CEO. He brings over three decades of experience in drug discovery and development, a career decorated with over 70 scientific publications and more than 60 patents. More importantly, he has played a leadership role in the development of three FDA-approved drugs, a rare accomplishment that provides immediate validation of his ability to translate complex science into tangible patient therapies.

Most recently, Dr. Skerlj served as President and CEO of Expansion Therapeutics, where he guided the company's work on a proprietary RNA-targeting platform. Before that, his leadership was instrumental at X4 Pharmaceuticals, a company he co-founded. There, he was a co-inventor of mavorixafor (Xolremdi), which received FDA approval in April 2024 as the first-ever treatment for WHIM syndrome, a rare and complex immunodeficiency disorder. His extensive resume also includes co-inventing plerixafor (Mozobil®), a stem cell mobilizer, and ertapenem (Invanz®), an anti-bacterial agent.

His track record demonstrates a deep understanding of the entire therapeutic pipeline, from initial discovery and preclinical development to navigating the rigorous clinical and regulatory pathways required for market approval. This experience is precisely what a venture-backed startup like Rhapsogen needs to transition from a promising scientific concept into a clinical-stage organization.

Catalio's Strategic Bet on Transformative Science

Rhapsogen's trajectory is heavily influenced by its backer, Catalio Capital Management. The New York-based investment firm, founded in 2020, has carved out a niche by focusing exclusively on innovative healthcare and life sciences companies. A core pillar of Catalio's strategy is to partner with world-renowned “serial scientist-entrepreneurs,” providing capital and strategic support to commercialize breakthrough biomedical technologies emerging from leading academic institutions.

Rhapsogen is a textbook example of this model in action. The company was launched through Catalio's venture strategy and is a key investment in its Catalio Nexus Fund IV, which closed in mid-2025 with over $400 million in commitments. The firm's deep involvement is further underscored by the fact that Rhapsogen co-founder Dr. Jeffrey Ravetch also serves as a Catalio Venture Partner, creating a synergistic relationship between the science and the capital.

The appointment of Dr. Skerlj is seen as a strategic move to de-risk the investment and maximize its potential. Catalio expressed strong confidence in the new leadership.

“Dr. Skerlj’s leadership experience coupled with his deep drug development expertise make him well suited to maximize the potential of Rhapsogen’s first-in-class approach in autoimmune disease,” commented Dr. Matthew Hobson, a Principal at Catalio who is also joining Rhapsogen’s Board of Directors. “We are thrilled to continue supporting the company’s growth under Dr. Skerlj’s leadership.”

A New Paradigm for Autoimmune Patients

Beyond the executive appointments and financial backing, the core of Rhapsogen's promise lies in its groundbreaking scientific approach. The company aims to tackle one of the most significant unmet needs in immunology: treating autoimmune diseases effectively without compromising the body's essential defense mechanisms.

Many current treatments for conditions like rheumatoid arthritis, lupus, and multiple sclerosis rely on broad immunosuppression. While these therapies can reduce autoimmune inflammation, they often leave patients vulnerable to serious infections. Rhapsogen’s mission is to develop next-generation therapies that can rapidly neutralize the specific pathogenic autoantibodies that cause disease while preserving the immune system’s overall ability to fight infection.

The scientific credibility for this ambitious goal comes directly from its co-founders. Dr. Jeffrey Ravetch is a giant in the field, renowned for his foundational discoveries on the Fc domain of antibodies and their corresponding receptors. His work has illuminated how subtle changes in antibody structure can dramatically alter their function, switching them from pro-inflammatory to anti-inflammatory agents. This research provides a powerful toolkit for engineering therapeutic antibodies with highly specific effects.

Complementing this expertise is Dr. Eric Sundberg, a distinguished structural biologist and protein engineer. Dr. Sundberg's research focuses on the molecular basis of immune interactions, providing the atomic-level blueprints needed to design and build novel protein therapeutics. The combination of Dr. Ravetch's deep biological insights and Dr. Sundberg's protein engineering prowess forms the scientific engine of Rhapsogen.

With a proven drug developer in the CEO chair, the strategic backing of a specialized investment firm, and a scientific platform rooted in the work of immunology pioneers, Rhapsogen is now fully equipped to pursue its mission. The company represents a confluence of talent, capital, and innovation aimed squarely at creating a new and better class of medicines for millions of patients worldwide living with autoimmune disease.