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

February 3, 2026 updated by: Ariceum Therapeutics GmbH

A Multicentre, Open-label, Phase I/II Study Investigating the Safety, Tolerability, and Preliminary Efficacy of 225Ac-SSO110 in Participants With Extensive Stage Small Cell Lung Cancer (ES-SCLC) or Merkel Cell Carcinoma (MCC) Receiving Standard of Care (SoC)

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).

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

2

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Australia
      • Alexandria, Australia
        • GenesisCare
  • United States
    • Florida
      • Miami, Florida, United States, 33165
        • Biogenix Molecular
    • Kentucky
      • Louisville, Kentucky, United States, 40202
        • University of Louisville Health-Brown Cancer Center
    • Maryland
      • Glen Burnie, Maryland, United States, 21061
        • United Theranostics
    • New Jersey
      • Hackensack, New Jersey, United States, 07601
        • John Theurer Cancer Center at Hackensack UMC
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15219
        • UPMC
    • Virginia
      • Fairfax, Virginia, United States, 22031
        • Virginia Cancer Specialists, PC

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  • 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 Exclusion 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 225Ac-SSO110 + SoC
Drug: 225Ac-SSO110 + SoC
Dose Level -2-7
Drug: Atezolizumab
Extensive Stage Small Cell Lung Cancer Checkpoint Inhibitor (SoC)
Drug: Durvalumab
Extensive Stage Small Cell Lung Cancer Checkpoint Inhibitor (SoC)
Drug: Avelumab
Merkel Cell Carcinoma Checkpoint Inhibitor (SoC)
Drug: Pembrolizumab
Merkel Cell Carcinoma Checkpoint Inhibitor (SoC)
Drug: Retifanlimab
Merkel Cell Carcinoma Checkpoint Inhibitor (SoC)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Part 1: Safety, tolerability, RP2D of 225Ac-SSO110 in combination with SoC
Time Frame: 42 days
Identification of the DLT rate per dose level
42 days
Part 2: Safety, tolerability, and preliminary anti-tumor activity of 225Ac-SSO110 in combination with SoC at RP2D
Time Frame: 42 days
Rate of serious adverse events, adverse events, laboratory parameters, and other safety findings, Preliminary anti-tumor activity of 225Ac-SSO110 as assessed by progression free survival (PFS), disease control rate (DCR), best observed response (BOR), overall response rate (ORR), duration of response (DoR)
42 days
Part 1 & 2: Safety and tolerability of 68Ga-SSO120
Time Frame: 7 days
Rate of serious adverse events, adverse events, laboratory parameters, and other safety findings
7 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ariceum Therapeutics GmbH

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 1, 2025

Primary Completion (Actual)

December 31, 2025

Study Completion (Actual)

December 31, 2025

Study Registration Dates

First Submitted

April 15, 2025

First Submitted That Met QC Criteria

April 15, 2025

First Posted (Actual)

April 22, 2025

Study Record Updates

Last Update Posted (Actual)

February 5, 2026

Last Update Submitted That Met QC Criteria

February 3, 2026

Last Verified

April 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SAX101
  • 2024-515041-42-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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