# Actithera

Source: https://onco.cc/companies/actithera/  
OnCo record `actithera` (Company). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Actithera designs small radioactive drugs that stick to a protein found around many solid tumours (FAP) and stay there longer, so more of the radiation reaches the cancer. Its first medicine was being prepared for human trials in 2026.

## Summary

Actithera is a radiopharmaceutical biotech headquartered in Oslo, Norway and Cambridge, Massachusetts. It was founded in 2021 by Andreas Goutopoulos with seed investors M Ventures and Arkin Bio Ventures II, and came into public view with a USD 75.5 million Series A in July 2025, co-led by M Ventures, Hadean Ventures, Sofinnova Partners and 4BIO Capital, with Bioqube Ventures, Innovestor, Investinor, Surveyor Capital and Arkin Bio Ventures II participating. Its discovery platform applies medicinal chemistry to small-molecule radioligands, including covalent-targeting chemistry licensed from the Weizmann Institute, to lengthen tumour residence time while keeping systemic clearance rapid; the company describes its approach as isotope-agnostic and suited to longer-lived radionuclides. The lead development candidate is directed at fibroblast activation protein (FAP), and the company's site says it has an asset in IND-enabling studies.

## Fields

- Kind: Company
- Last checked: 2026-10-29
- HQ: Cambridge, MA
- Type: radiopharma
- Website: https://actithera.com/

## Notes

- Included because the July 2025 Series A was its first announced financing; the founding year (2021) and investors are from the company's own Series A press release of 9 July 2025. The isotope for the FAP candidate is not disclosed. Steven Kelly is named as CEO on the current website; the Series A release named Goutopoulos as founder and CEO.

## Sources

- Official website: https://actithera.com/
- Series A press release (PDF): https://actithera.com/wp-content/uploads/2025/07/250709-Actithera-Series-A-PR-Final.pdf
- BioPharma Dive: Actithera Series A: https://www.biopharmadive.com/news/actithera-radiopharmaceutical-cancer-series-a/752493/
- News and press: https://actithera.com/recent-news-press/

## Connected records

- fronts: [Radiopharmaceuticals & Theranostics](https://onco.cc/fronts/radiopharma/)
- technologies: [Radioligand therapy (beta emitters)](https://onco.cc/technologies/radioligand-therapy/)
- targets: [FAP](https://onco.cc/targets/fap/)
- companies: [Sofinnova Partners](https://onco.cc/companies/sofinnova-partners/)

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