FDA Clears Ariceum Therapeutics’ ²²⁵Ac-Satoreotide Phase I/II Clinical Study in Patients with Small Cell Lung Cancer or Merkel Cell Carcinoma

• ²²⁵Ac-SSO110 (satoreotide) is a first in class Actinium-labelled SSTR2 receptor antagonist
• Phase I/II SANTANA-225 study on track to enrol patients in Q1 2025

Berlin, Germany, 14 January 2025 – Ariceum Therapeutics (Ariceum), a private biotech company developing radiopharmaceutical products for the diagnosis and treatment of certain hard-to-treat cancers, today announced that the US Food and Drug Administration (FDA) has cleared its investigational new drug (IND) application to commence a Phase I/II clinical trial (‘SANTANA-225’) of its proprietary radiolabelled peptide, ²²⁵Ac-SSO110, in patients with small cell lung cancer (SCLC) or Merkel Cell Carcinoma (MCC).

The SANTANA-225 trial is a global, open-label Phase I/II study, that will assess the safety, tolerability, preliminary efficacy and recommended Phase II dose of ²²⁵Ac-SSO110 in patients with extensive-stage SCLC or MCC who are on first-line maintenance therapy with checkpoint inhibitors. Ariceum is working with its partners and clinical sites in the US and other countries to commence recruitment of patients in Q1 2025.

Germo Gericke, Chief Medical Officer at Ariceum Therapeutics, said: “This is an important milestone, not only for Ariceum but for the whole field of targeted radionuclide cancer treatments. ²²⁵Ac-SSO110 is the first somatostatin receptor 2 (SSTR2) antagonist labelled with Actinium-225 to undergo human trials, providing the optimum combination of a long half-life α particle emitter with a long tumour retention tracer. Based on encouraging clinical data with ¹⁷⁷Lu-SSO110 and very promising pre-clinical data of ²²⁵Ac-SSO110, we are very optimistic about the potential for patients with difficult to treat cancers.”

²²⁵Ac-SSO110 is being developed together with its companion patient selection tracer ⁶⁸Ga-SSO120 as a ‘theranostic pair’ targeted radionuclide treatment of multiple indications expressing SSTR2, such as SCLC, MCC, and other aggressive cancers. Ariceum has recently expanded its global supply agreements for the medical radionuclides Actinium-225 (²²⁵Ac) and Lutetium-177 (¹⁷⁷Lu), which will be used to radiolabel SSO110.

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About Ariceum Therapeutics
Ariceum Therapeutics is a private, clinical stage radiopharmaceutical company focused on the diagnosis and precision treatment of certain neuroendocrine and other aggressive, hard-to-treat cancers. The name Ariceum is an anagram of ‘Marie Curie’ whose discovery of radium and polonium have been huge contributions to finding treatments for cancer.

Ariceum’s lead targeted systemic radiopharmaceutical candidate, SSO110 (“satoreotide”) labelled with Lutetium-177 (¹⁷⁷Lu) and Actinium-255 (²⁵⁵Ac) is an antagonist of the somatostatin type 2 (SSTR2) receptor which is overexpressed in aggressive neuroendocrine tumours (NETs) such as small cell lung cancer (SCLC) or Merkel Cell Carcinoma (MCC), all of which have limited treatment options and poor prognosis. Satoreotide is being developed as a ‘theranostic pair’ for the combined diagnosis and targeted radionuclide treatment of these tumours. Ariceum is also developing a radiolabelled PARP-inhibitor (ATT001), currently in Phase 1 clinical development under the trial name CITADEL-123. ATT001 was part of the acquisition of Theragnostics Ltd which was closed in June 2023.

Ariceum Therapeutics, launched in 2021, acquired all rights to satoreotide from Ipsen, which has remained a shareholder of the Company. Ariceum is headquartered in Berlin, with operations in Germany, Switzerland, Australia, the United Kingdom, and the United States.

Ariceum is led by a highly experienced management team and supported by specialist investors including EQT Life Sciences (formerly LSP), HealthCap, Pureos Bioventures, Andera Partners, and Earlybird Venture Capital. For further information, please visit www.ariceum-therapeutics.com.

For further information, please contact:

Ariceum Therapeutics
Manfred Rüdiger, CEO
Email: info@ariceum-therapeutics.com

Optimum Strategic Communications
Zoe Bolt, Charlotte Hepburne-Scott, Elena Bates
Tel: +44 (0) 20 3882 9621
Email: ariceum@optimumcomms.com