Dover, Del.–Â Precisio Biotix Therapeutics has announced the first patient has been dosed with its novel staph lysin, ClyO (LYSG101), in a compassionate use case approved by the FDA. The treatment was administered at Mayo Clinic to a patient suffering from a persistent prosthetic joint infection that had not responded to conventional therapies.
The patient reportedly tolerated the treatment well, with no adverse events observed. While it is too early to determine full efficacy, the milestone represents a significant advance in the use of lysins—engineered enzymes designed to break down bacterial cell walls—to treat multidrug-resistant infections.
“Our company’s mission is to systematically engineer lysins that combat antimicrobial-resistant pathogens,” said Dr. Raymond Schuch, Vice President and Director of U.S. Operations at Precisio. “We’ve previously focused on respiratory, skin, and vaginal infections, and we’re now expanding to prosthetic joint infections—an area with urgent unmet need.”
Lysins are a promising class of antimicrobials that act by directly lysing bacteria rather than inhibiting growth like traditional antibiotics. This direct action offers rapid bacterial clearance and a lower risk of resistance development, making them ideal for tackling drug-resistant infections. ClyO is designed to target Staphylococcus aureus, a common cause of prosthetic joint infections.
Mark Engel, Founder and CEO of Precisio, emphasized the company’s technology-driven approach to lysin development. “We are a platform-plus-products company,” he said. “Our proprietary bioinformatics and AI tools, including Zeus™ and LysiThru™, allow us to engineer optimized lysins that can be tailored to a range of infections. We believe ClyO is just the beginning—many physicians are already eager to use these therapies under compassionate use programs.”
Dr. Assaf Raz, Vice President of Research and Development, noted the growing urgency to find alternatives to antibiotics. “Antimicrobial resistance is a global crisis, and current estimates suggest up to 10 million deaths annually by 2050 if left unchecked. Our lysins offer a new path forward by bypassing resistance mechanisms entirely.”
Engel added that the company is now seeking strategic and financial partnerships to accelerate development and bring lysin-based treatments to broader markets, including low- and middle-income countries. “We’re building lysins that are potent, stable, and cost-effective. That opens the door to improving outcomes on a global scale.”
With this first successful human administration of ClyO, Precisio aims to expand its lysin programs to treat a wide range of drug-resistant bacterial infections—offering new hope in the fight against superbugs.
