4BIO Capital co-leads Actithera’s oversubscribed $75.5 million Series A financing

4BIO investing in unique radiopharmaceutical platform company, developing radioligands with prolonged tumour retention

Series A was co-led by 4BIO Capital, founding investor M Ventures, Hadean Ventures, and Sofinnova Partners, with syndicate including Bioqube Ventures, Surveyor Capital (a Citadel company) and others

Proceeds will support clinical development of Actithera’s fibroblast activation protein (FAP)-targeting candidate and pipeline expansion

London, United Kingdom, 9 July 2025 – 4BIO Capital (“4BIO” or “the Group”), an international venture capital firm unlocking the treatments of the future by investing in advanced therapies and other emerging technologies, today announces that it has co-led a $75.5 million Series A Financing round of Actithera (the “Company”).

Radiopharmaceutical therapy (or radioligand therapy, RLT) is a targeted form of radiotherapy that can treat cancers resistant to other therapies and represents a $7.5 billion market projected to grow to $14.4 billion by 2034¹. RLTs with the appropriate pharmacokinetic profile can achieve efficacy with minimal toxicity; however, attaining the ideal pharmacokinetic characteristics is not trivial. 4BIO's investment in Actithera highlights the clear need for a more systematic approach to optimizing RLT vectors and exemplifies the Group’s strategy of identifying critical technology gaps, backing innovative solutions, and supporting them in high-growth markets.

4BIO co-led the oversubscribed round alongside founding investor M Ventures, Hadean Ventures, and Sofinnova Partners with additional participation from Bioqube Ventures, Innovestor’s Life Science Fund, Investinor, Surveyor Capital (a Citadel company), and the second founding investor, Arkin Bio Ventures II.

Therese Liechtenstein, incoming Board Member and Investment Director at 4BIO Capital, said: “At 4BIO we invest in companies solving technical unmet needs to enable next-generation therapeutics. We are honoured to support Actithera, whose pipeline of molecules addresses key challenges in the nascent radioligand therapies space; a large therapeutic window through high tumour retention and low systemic exposure, applied to a lead programme that has significant pan-tumour therapeutic potential.”

Dr Andreas Goutopoulous, Founder and CEO of Actithera, added: “We are grateful for 4BIO Capital’s support in this oversubscribed Series A, which is a strong validation of our approach. We set out to bring structure-based and kinetics-driven thinking from small molecule drug design into the world of radiopharmaceuticals. We engineer our radioconjugates for extended retention within tumours, making them ideally suited for longer-lived radionuclides and ultimately delivering more convenient dosing schedules and enhanced efficacy and safety for patients.”

As part of the Series A financing, Therese Liechtenstein, Investment Director at 4BIO Capital will join the Actithera Board of Directors.

The financing will support the advancement of Actithera’s lead FAP asset into clinical development in multiple indications, while also enabling the continued development of its proprietary RLT discovery platform and preclinical pipeline.

The Company’s discovery platform combines rational drug design with radiochemistry to create novel small molecule radioligands that overcome current limitations in radiopharmaceutical development. Its three-pillar platform includes first-in-class covalent targeting strategies, designed to optimize tumour residence time, while ensuring rapid systemic clearance – improving precision, safety, and efficacy. Two additional proprietary approaches further support compound differentiation and improve tumour residence time and selectivity. This platform was validated through Actithera’s work on FAP, a high-value theranostic target known for being difficult to drug with molecules that maintain prolonged tumour residency. These efforts have resulted in a FAP-directed RLT development candidate with best-in-class potential due to its optimal pharmacokinetic profile and tumour specificity.

Dr Andreas Goutopoulos, founder and CEO, brings over 25 years of pharmaceutical and biotech industry experience, including a track record of more than a dozen development candidates. His background includes over a decade of discovery leadership at EMD Serono, where he led medicinal chemistry. In his role as Entrepreneur-in-Residence (EIR) at M Ventures, he led the scientific efforts of and supported a number of oncology small molecule biotechs. At Actithera, he is pioneering a chemistry-driven, precision approach to RLTs by integrating novel covalent-targeting chemistries, rational drug design principles and an isotope-agnostic philosophy.

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Contacts

About 4BIO Capital
4BIO Capital (“4BIO”) is an international venture capital firm focused on investing in advanced therapies and emerging modalities, to unlock the treatments of the future. 4BIO’s mission is to invest in, support, and grow early-stage companies solving technical bottlenecks that enable next generation therapeutics in areas of high unmet medical need, with the ultimate goal of ensuring access to these potentially transformative therapies for all patients. The 4BIO team comprises leading advanced therapy scientists and experienced life science investors with an unrivalled network within the advanced therapy sector and a unique understanding of the criteria that define a successful investment opportunity in this space. For more information, connect with us on LinkedIn and Twitter @4biocapital and visit www.4biocapital.com.

About Actithera
Actithera is a radiopharmaceutical biotech company translating medicinal chemistry insights into next-generation radioligand therapies (RLTs). Founded in 2021 by drug discovery innovator Dr. Andreas Goutopoulos, and seed investors M Ventures, and Arkin Bio-Holdings, Actithera applies various molecular design strategies, including covalent-targeting and an isotope-agnostic philosophy to invent RLTs with significant differentiation and larger therapeutic windows. Headquartered in Oslo, Norway, and Cambridge, Massachusetts, Actithera is committed to advancing a differentiated pipeline addressing critical unmet needs in oncology. Learn more at www.actithera.com and on LinkedIn.

¹ https://www.precedenceresearch.com/radiopharmaceuticals-market

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