Study of 225Ac-SS0110 in Subjects With ES-SCLC or MCC (SANTANA-225 )

Study summary

This study aims to determine safety, tolerability, recommended phase 2 dose (RP2D), and preliminary antitumor activity of 225Ac-SSO110 with standard of care (SoC) therapy in patients with somatostatin receptor 2 expressing (SSTR2+) extensive-stage small cell lung cancer (ES-SCLC) and recurrent locally advanced or metastatic Merkel cell carcinoma (MCC).

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Key things to know

Main goalTreatment

This describes the study’s primary purpose.

What is being studied225Ac-SSO110 + SoC and Atezolizumab

Plus 4 other study approaches.

Who it may be forSmall cell lung cancer (SCLC) · Locally advanced · Metastatic or stage IV

These are broad labels—not an eligibility decision.

Checked against the public recordLast updated Feb 5, 2026 · Source: ClinicalTrials.gov

Is enrollment open?Terminated

Ask the study team to confirm whether enrollment is open.

What kind of study?Phase 1 / Phase 2

Interventional

Where is it offered?7 U.S. locations

Locations may change over time.

Who runs it?Ariceum Therapeutics GmbH

Study sponsor

Study overview

What this study is about

Purpose: Treatment
Study type: Interventional
Phase: Phase 1 / Phase 2
Sponsor: Ariceum Therapeutics GmbH
Interventions being studied: Drug: 225Ac-SSO110 + SoC; Drug: Atezolizumab; Drug: Durvalumab; Drug: Avelumab; Drug: Pembrolizumab; Drug: Retifanlimab

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How this study is categorized

These labels come from structured fields and exact terms in the public record.

Cancer type

Small cell lung cancer (SCLC)→

Disease setting

Locally advanced→Metastatic or stage IV→Recurrent or relapsed→

Treatment approach

Immunotherapy→

Public criteria

Who may be able to participate

The sponsor separates these requirements into two groups. You do not need to interpret them alone—use them to guide a conversation with the study team.

Requirements people may need to meetInclusion criteria

Key
Signed Informed Consent Form and willing to comply with all study procedures.
Participants with ES-SCLC (defined as Stage IV per NCCN guidelines Version 1.2024) or recurrent locally advanced or metastatic MCC (per NCCN guidelines Version 1.2024) documented by histology or cytology.
Participants eligible to receive immune checkpoint inhibitor (CPI) monotherapy at the start of treatment with 225Ac-SSO110 or patients already on CPI monotherapy for 7 weeks.
ECOG performance status of 0 or 1. Life expectancy of at least 6 months.
Positive 68Ga-SSO120 scan (Investigator-assessed) during screening. Key

Reasons someone may not be able to joinExclusion criteria

Participants with unstable spinal cord compression.
Any previous systemic radioligand therapy or extensive radiotherapy.
Participants receiving or planned to receive consolidative chest radiation.
History of primary immunodeficiency, transplantation or CAR-T cell therapy.
Major surgical procedure except diagnostic biopsy within 28 days prior to enrolment or scheduled to have major surgery during the study.
Inadequate organ or marrow function.

Important: This is the sponsor’s public criteria, not a determination of eligibility. The study team must review your individual situation.

Study sites

U.S. locations

Biogenix MolecularMiami, Florida
University of Louisville Health-Brown Cancer CenterLouisville, Kentucky
United TheranosticsGlen Burnie, Maryland
John Theurer Cancer Center at Hackensack UMCHackensack, New Jersey
UPMCPittsburgh, Pennsylvania
Virginia Cancer Specialists, PCFairfax, Virginia
GenesisCareAlexandria

Source and freshness
Processed from ClinicalTrials.gov. Last public update: Feb 5, 2026. Always confirm current availability with the study team.

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