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

NCT06939036 | Terminated Phase 1 DMC FDA Drug

• 2 other identifiers: SAX1012024-515041-42-00
• Study Type: interventional
• Target: 2
• Locations: 2 countries
• Sites: 7

Brief 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).

Conditions

Small Cell Lung Cancer Extensive Stage; Merkel Cell Carcinoma

Keywords

actinium; 225Ac; actinium-225; SSO110; SSO120; gallium; 68Ga; gallium-68; radiopharmaceutical; MCC; Merkel Cell carinoma; ES-SCLC; Extensive Stage Small Cell Lung Cancer; radioligand; somatostatin receptor 2; JR11; sstr2-antagonist

Outcome Measures

Primary Outcomes (3)

• Part 1: Safety, tolerability, RP2D of 225Ac-SSO110 in combination with SoC

  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

  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

  Rate of serious adverse events, adverse events, laboratory parameters, and other safety findings

  7 days

Study Arms (1)

225Ac-SSO110 + SoC

EXPERIMENTAL

Drug: 225Ac-SSO110 + SoC; Drug: Atezolizumab; Drug: Durvalumab; Drug: Avelumab; Drug: Pembrolizumab; Drug: Retifanlimab

Interventions

225Ac-SSO110 + SoC DRUG

Dose Level -2-7

225Ac-SSO110 + SoC

Atezolizumab DRUG

Extensive Stage Small Cell Lung Cancer Checkpoint Inhibitor (SoC)

225Ac-SSO110 + SoC

Durvalumab DRUG

Extensive Stage Small Cell Lung Cancer Checkpoint Inhibitor (SoC)

225Ac-SSO110 + SoC

Avelumab DRUG

Merkel Cell Carcinoma Checkpoint Inhibitor (SoC)

225Ac-SSO110 + SoC

Pembrolizumab DRUG

Merkel Cell Carcinoma Checkpoint Inhibitor (SoC)

225Ac-SSO110 + SoC

Retifanlimab DRUG

Merkel Cell Carcinoma Checkpoint Inhibitor (SoC)

225Ac-SSO110 + SoC

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Ariceum Therapeutics GmbH: lead

Study Sites (7)

Biogenix Molecular

Miami, Florida, 33165, United States

Location

University of Louisville Health-Brown Cancer Center

Louisville, Kentucky, 40202, United States

Location

United Theranostics

Glen Burnie, Maryland, 21061, United States

Location

John Theurer Cancer Center at Hackensack UMC

Hackensack, New Jersey, 07601, United States

Location

UPMC

Pittsburgh, Pennsylvania, 15219, United States

Location

Virginia Cancer Specialists, PC

Fairfax, Virginia, 22031, United States

Location

GenesisCare

Alexandria, Australia

Location

MeSH Terms

Conditions

Carcinoma, Merkel Cell

Interventions

atezolizumab; durvalumab; avelumab; pembrolizumab

Condition Hierarchy (Ancestors)

Polyomavirus Infections; DNA Virus Infections; Virus Diseases; Infections; Tumor Virus Infections; Carcinoma, Neuroendocrine; Neuroendocrine Tumors; Neuroectodermal Tumors; Neoplasms, Germ Cell and Embryonal; Neoplasms by Histologic Type; Neoplasms; Adenocarcinoma; Carcinoma; Neoplasms, Glandular and Epithelial; Neoplasms, Nerve Tissue

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 15, 2025
• First Posted: April 22, 2025
• Study Start: July 1, 2025
• Primary Completion: December 31, 2025
• Study Completion: December 31, 2025
• Last Updated: February 5, 2026

Record last verified: 2025-04

Data Sharing

• IPD Sharing: Will share

Locations

AU (1); US (6)