Maxion Therapeutics

Maxion Therapeutics is a Cambridge-based biotechnology company developing a new class of antibody-based drugs — KnotBodies® — for diseases involving ion channels and G protein-coupled receptors (GPCRs). These two target classes are implicated in a vast range of conditions including chronic pain, autoimmune diseases, and cardiovascular disorders, but have historically been considered extremely difficult to address with biologics. Traditional antibodies struggle to access the compact, three-dimensional binding sites on ion channels and GPCRs, resulting in a major therapeutic gap that Maxion's platform is specifically designed to bridge.

The KnotBody® technology works by fusing knottins — cysteine-rich miniproteins that have naturally evolved over millions of years to modulate ion channels — into the binding loops of antibodies. The resulting hybrid molecules combine the precise, high-potency targeting of knottins with the superior pharmacokinetics, selectivity, and long-acting durability of antibody drugs. This creates a novel biologic modality with first-in-class potential across multiple disease areas. Maxion's lead programme, MAX001, is in preclinical development targeting a broad spectrum of inflammatory diseases including atopic dermatitis and inflammatory bowel disease, with additional early-stage programmes in pain and cardiovascular disease.

Maxion was founded in 2020 by Dr. John McCafferty and Dr. Aneesh Karatt-Vellatt, both co-founders of IONTAS (acquired by FairJourney Biologics), and is led by CEO Dr. Arndt Schottelius. In March 2025, the company closed a $72 million Series A — described as one of the largest European private biotech financings since early 2024 — led by General Catalyst, with backing from British Patient Capital, Solasta Ventures, Eli Lilly, LifeArc Ventures, Monograph Capital, and BGF. Total funding to date stands at approximately $88 million.