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British Patient Capital announces £10m investment in Maxion Therapeutics as part of £58m Series A Financing Round

Press release 17 March 2025

British Patient Capital, a commercial subsidiary of the British Business Bank, has made a £10m investment in Maxion Therapeutics, a biotechnology company developing antibody-based KnotBody® drugs for ion channel and G protein coupled receptor (GPCR) driven diseases, as part of a £58m ($72) million Series A financing round.

The round was led by General Catalyst with additional investment from new investors, British Patient Capital, Solasta Ventures and Eli Lilly and Company and supported by existing investors LifeArc Ventures, Monograph Capital and BGF.

The financing will be used to develop Maxion’s proprietary KnotBody technology, taking the programme to clinical proof of concept and advance its opportunity to address large global markets.

Maxion’s lead KnotBody programme, MAX001, is currently in preclinical development to target a broad spectrum of inflammatory diseases such as atopic dermatitis and inflammatory bowel disease. Other early-stage programmes include KnotBody molecules for the treatment of pain and cardiovascular disease.

Ion channel and GPCR dysfunction is implicated in a wide range of debilitating diseases and current treatments, based on small molecule drugs, often suffer from poor efficacy and side effects due to the lack of selectivity and exposure. Compared to small molecules, engineered antibodies offer superior selectivity and are well proven therapeutically. Despite these obvious advantages, antibody discovery against ion channels and GPCRs has been very challenging with no antibodies against ion channels currently in clinical development.

Co-founders Dr. John McCafferty and Dr. Aneesh Karatt-Vellatt developed Maxion’s revolutionary KnotBody technology, which combines the benefits of knottins (cysteine-rich mini-proteins which are natural ion channel modulators) with antibodies, creating safe, efficacious, long-acting ion channel modulators.

Following this fundraising, Elena Viboch, Managing Director at General Catalyst and Emma Johnson, Senior Investment Manager, Life Sciences at British Patient Capital will join the Maxion Board.

Arndt Schottelius, MD PhD, Chief Executive Officer at Maxion Therapeutics, said:

This landmark fundraising – one of the largest European private biotech financings since the beginning of 2024 – highlights the significant potential of our technology and development pipeline. KnotBodies represent a potential breakthrough biologic drug modality, delivering greater potency, selectivity, and durability. We believe that they will provide transformational new therapeutic options for ion channel- and GPCR-driven diseases, across a wide range of therapeutic areas with a remaining high unmet medical need. The calibre of our international investor syndicate validates our approach, and I would like to welcome our new investors to Maxion and thank our existing investors for their continued support.

Leandros Kalisperas, Chief Investment Officer at the British Business Bank, said:

We provide critical growth funding for companies with breakthrough science and technology. The UK is a world leader in life sciences, but startups in the sector depend on multiple rounds of funding for research and development. Our direct investing team specialise in investing in high-potential, R&D intensive companies like Maxion Therapeutics. By helping them to launch innovative products and commercialise, we stimulate growth, create jobs, and build the UK's scientific ecosystem.

Emma Johnson, Senior Investment Manager – Life Sciences, Direct & Co-Investments, British Patient Capital, said:

We're excited to support Maxion at a pivotal stage in their development and realise the potential of the KnotBody platform. This advances the field of antibody therapeutics, opening up new target classes to ultimately benefit patients, and builds on the successes of the UK's contributions to the global biologics market.

Elena Viboch, Managing Director at General Catalyst, said:

We believe Maxion is radically shifting the biologics discovery process to address the most challenging drug targets such as ion channels and GPCRs. With a strong team and differentiated platform, Maxion is well-positioned to discover and develop medicines that matter.

Further Information

Notes to editors

About British Patient Capital

British Patient Capital Limited is a wholly owned commercial subsidiary of British Business Bank plc, the UK government’s economic development bank. Its mission is to enable long-term investment in innovative firms led by ambitious entrepreneurs who want to build large-scale businesses. Launched in June 2018, British Patient Capital has more than £3bn of assets under management, investing in venture and venture growth capital to support high growth potential innovative UK businesses in accessing the long-term financing they require to scale up.

British Business Bank plc and its subsidiary entities are not banking institutions and do not operate as such. They are not authorised or regulated by the Prudential Regulation Authority (PRA) or the Financial Conduct Authority (FCA). A complete legal structure chart for British Business Bank plc and its subsidiaries can be found on the British Business Bank plc website

British Patient Capital makes commitments and invests on its own behalf and on behalf of third-party investors whose investments British Patient Capital manages.

The transaction described above does not constitute or imply any endorsement, warranty or recommendation by the UK government, the British Business Bank plc, its subsidiaries or any other party in respect of Maxion Therapeutics.

About Maxion Therapeutics

Maxion Therapeutics is a biotechnology company developing antibody-based drugs for previously untreatable ion channel- and G protein-coupled receptor (GPCR)-driven diseases, including autoimmune conditions, chronic pain, and cardiovascular disease.

The Company is developing a pipeline of potentially first- and best-in-class therapeutics using its proprietary KnotBody technology to generate potent, selective, and long-acting therapeutics by combining naturally occurring mini-proteins (‘knottins’) with antibodies using state-of-the-art phage and mammalian display technologies.

Maxion was founded in 2020 by highly respected biotech entrepreneurs and scientists Dr John McCafferty, CTO and Dr Aneesh Karatt-Vellatt, CSO. Dr McCafferty previously co-invented antibody phage display, which was the subject of the 2018 Nobel Prize in Chemistry awarded to his co-inventor Sir Gregory Winter. Maxion’s portfolio and growth is being advanced by a team of highly experienced leaders in the discovery and development of antibody-based drugs. The Company is based near Cambridge, UK and is backed by international blue-chip investors. For more information, please visit: Maxion Therapeutics 

About General Catalyst

General Catalyst is a global investment and transformation company that partners with the world’s most ambitious entrepreneurs to drive resilience and applied AI. We support founders with a long-term view who challenge the status quo, partnering with them from seed to growth stage and beyond. With offices in San Francisco, New York City, Boston, Berlin, Bangalore, and London, we have supported the growth of 800+ businesses, including Airbnb, Anduril, Applied Intuition, Commure, Glean, Guild, Gusto, Helsing, Hubspot, Kayak, Livongo, Mistral, Ramp, Samsara, Snap, Stripe, Sword, and Zept. For more information, please visit: General Catalyst 

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