Maxion Therapeutics is a biotechnology company based in Cambridge, UK, that develops antibody-based drugs for diseases driven by ion channels and G protein-coupled receptors (GPCRs). Its proprietary KnotBody platform combines knottins, naturally evolved ion channel modulators, with antibody engineering, with the aim of producing biologics with the selectivity of antibodies against targets that conventional antibodies have struggled to reach.

The company is focused on chronic pain, autoimmune disorders and cardiovascular disease, areas where it states that more than a billion people are inadequately treated or lack effective therapies. Its lead KnotBody programme, MAX001, is being advanced towards clinical proof-of-concept, with additional programmes moving towards the clinic.

Maxion was founded in 2020 by John McCafferty and Aneesh Karatt-Vellatt, who previously co-founded Cambridge Antibody Technology and IONTAS. McCafferty co-invented antibody phage display, the technology behind Humira. The company is led by CEO Arndt Schottelius.

Maxion raised a $16M financing in February 2023 led by LifeArc Ventures, with Monograph Capital and BGF participating, and received a £2M Innovate UK grant in April 2023. In March 2025 it closed a $72M Series A led by General Catalyst, with British Patient Capital, Solasta Ventures and Eli Lilly and Company joining existing investors LifeArc Ventures, Monograph Capital and BGF.