Study in Advanced Solid Tumor Patients

A Phase 1/2 Study of CLIO-8221 in Patients With Advanced Solid Tumors

The study will be conducted in 2 phases: Phase 1: Dose-escalation and Dose Level Expansion, Phase 1 will determine the maximum tolerated dose (MTD) and/or recommended dose for expansion (RDE). Phase 2: Tumor-Specific Expansions with Dose Optimization, Phase 2 will further evaluate CLIO-8221 in tumor-specific expansion cohorts to optimize dosing and assess preliminary efficacy.

Study Overview

• Status: Recruiting
• Conditions: Advanced Solid Tumor
• Intervention / Treatment: Drug: CLIO-8221

Detailed Description

Phase 1: Dose-escalation and Dose Level Expansion. Dose escalation safety data will be reviewed by a Safety Monitoring Committee (SMC) to guide dosing decisions. Backfill enrollment may be used to further characterize safety, PK/PD, and antitumor activity.

Phase 2: Tumor-Specific Expansions with Dose Optimization. Phase 2 will further evaluate CLIO-8221 in tumor-specific expansion cohorts to optimize dosing and assess preliminary efficacy. Safety, tolerability, PK/PD, and response data will support selection of the recommended Phase 2 dose (RP2D) for further development.

• Study Type: Interventional
• Enrollment (Estimated): 306
• Phase: Phase 2; Phase 1

Contacts and Locations

• Study Contact: Name: CMO; Phone Number: 206-602-3134; Email: clinical@calliotx.com

Study Locations

• Australia
  • New South Wales
    • Randwick, New South Wales, Australia, 2031
      • Recruiting
      • Scientia Clinical Research
      • Contact: Charlotte Lemech, Dr; Phone Number: 0293825800; Email: charlotte.lemech@scientiaclinicalresearch.com.au
  • Queensland
    • South Brisbane, Queensland, Australia, 4101
      • Recruiting
      • Integrated Clinical Oncology Network Pty Ltd
      • Contact: Jermaine Coward, Dr; Phone Number: 0737374500; Email: drjcoward@iconcancercare.com.au
  • Victoria
    • Box Hill, Victoria, Australia, 3128
      • Recruiting
      • Peter MacCallum Cancer Centre
      • Contact: Stephen Luen, Dr; Phone Number: 0385595000; Email: Stephen.Luen@petermac.org
    • Heidelberg, Victoria, Australia, 3084
      • Recruiting
      • AlfredHealth
      • Contact: Malaka Ameratunga, Dr; Phone Number: 0390763129; Email: malaka.ameratunga@austin.org.au
    • Melbourne, Victoria, Australia, 3052
      • Recruiting
      • Royal Melbourne Hospital
      • Contact: Stephen Luen, Dr; Phone Number: 0385595000; Email: Stephen.Luen@petermac.org
  • Western Australia
    • Nedlands, Western Australia, Australia, 6009
      • Recruiting
      • Linear Clinical Research Ltd
      • Contact: Peter Lau, Dr; Phone Number: 0863825100; Email: actcstartup@linear.org.au
• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02215-5450
      • Not yet recruiting
      • DFCI
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Recruiting
      • Sarah Cannon Research Institute 335 24th Avenue North, Suite 400
      • Contact: SCRI Patient Intake Team
      • Contact: Phone Number: 615-329-7640; Email: SCRINewPatient@USONCOLOGY.com
      • Principal Investigator: Dr. Hamilton (Erika Paige Hamilton)
  • Texas
    • Houston, Texas, United States, 77030
      • Recruiting
      • MD Anderson Cancer Center
      • Contact: Desirae Dufner, Dr; Phone Number: 713-745-7813; Email: ddufner@mdanderson.org
    • San Antonio, Texas, United States, 78229
      • Recruiting
      • START San Antonio
  • Utah
    • West Valley City, Utah, United States, 84119
      • Recruiting
      • START Mountain

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with advanced solid tumors
• Patients must have metastatic or unresectable disease not suitable for further local treatment and should have received prior beneficial therapies unless ineligible, unwilling, or lacking access.
• LVEF ≥50% by echocardiogram (ECHO) or multigated acquisition (MUGA) scan.
• An Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1
• Measurable disease per RECIST version 1.1 at baseline

Exclusion Criteria:

• Prior anti-tumor treatment with an ATRi.
• Prior or concurrent malignancy whose natural history or treatment has the potential to interfere with the safety or efficacy assessment of the investigational regimen. Exceptions are malignancies with a negligible risk of metastasis or death (e.g., 5-year OS ≥90%), including, but not limited to, adequately treated carcinoma in situ of the cervix, non-melanoma skin carcinoma, localized prostate cancer, ductal carcinoma in situ, and Stage I uterine cancer.
• History of uncontrolled seizure disorders or clinically significant neurodegenerative disorders, including progressive peripheral neuropathy. Stable Grade ≤ 2 peripheral neuropathy is allowed.
• Clinically significant autoimmune disease, either currently present or present within the previous 2 years, including a current requirement for systemic immunosuppressive therapy equivalent to >10 mg/prednisone daily (local immunosuppressive therapy such as inhaled or topical corticosteroids is allowed).
• Any uncontrolled Grade ≥ 3 (per NCI CTCAE version 6.0) viral, bacterial, or fungal infection within 2 weeks prior to Cycle 1 Day 1. Routine antimicrobial prophylaxis is permitted.
• History of hepatic cirrhosis, autoimmune hepatitis, or drug-associated hepatitis within the past 12 months.
• Uncontrolled diabetes mellitus, defined as Hgb A1c ≥8% or Hgb A1c between 7% and <8% with associated diabetes symptoms (polyuria or polydipsia) that are not otherwise explained.
• Any other medical, social, or psychosocial factors that, in the opinion of the investigator, could impact safety or compliance with study procedures.

Additional protocol defined inclusion/exclusion criteria may apply

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dose escalation and dose level expansion; Phase 1: CLIO-8221 monotherapy in escalating doses. Phase 2: Phase 2 will be initiated in tumor-specific expansion cohorts at selected doses.	Drug: CLIO-8221; intravenous (IV) infusion

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Type, incidence, severity, and seriousness of adverse events (AEs)	Type, incidence, severity, and seriousness of AEs occurred	Through end of treatment, up to approximately 2 years.
Type, incidence, and severity of laboratory abnormalities	Type, incidence, and severity of laboratory abnormalities occurred	Through end of treatment, up to approximately 2 years.
Incidence of dose limiting toxicities dose (RP2D) of CLIO-8221	Incidence of dose limiting toxicities occurred	From first dose through study day 21.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate	Participants who achieve partial or complete response per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 criteria	Through disease progression, up to approximately 2 years.
Disease control rate	Participants who achieve stable disease, partial or complete response per RECIST v1.1 criteria	Through disease progression, up to approximately 2 years.
Progression-free survival	Time from first dose of CLIO-8221 to disease progression or death, whichever occurs first	Up to approximately 2 years.
Duration of objective response	Time from the first documented objective tumor response (complete or partial), subsequently confirmed, to radiographic progression or death	From the date of enrollment until a confirmed partial or complete response is achieved, assessed up to 2 years.
Pharmacokinetic Parameter Area Under the Curve (AUC) for CLIO-8221	Measure of CLIO-8221 AUC in plasma	Varying timepoints through end of treatment, up to approximately 2 years.
Pharmacokinetic Parameter Maximum Concentration (Cmax) for CLIO-8221	Measure of CLIO-8221 Cmax in plasma	Varying timepoints through end of treatment, up to approximately 2 years.
Pharmacokinetic Parameter Time to Maximum Concentration (Tmax) for CLIO-8221	Measure of CLIO-8221 Tmax in plasma	Varying timepoints through end of treatment, up to approximately 2 years.
Pharmacokinetic Parameter Total Clearance (CL) for CLIO-8221	Measure of CLIO-8221 CL in plasma	Varying timepoints through end of treatment, up to approximately 2 years.
Pharmacokinetic Parameter Volume of distribution at steady state (Vd) for CLIO-8221	Measure of CLIO-8221 Vd in plasma	Varying timepoints through end of treatment, up to approximately 2 years.
Pharmacokinetic Parameter Apparent Terminal Half-life (t1/2) for CLIO-8221	Measure of CLIO-8221 t1/2 in plasma	Varying timepoints through end of treatment, up to approximately 2 years.

Collaborators and Investigators

• Sponsor: Callio Therapeutics

Study record dates

Study Major Dates

• Study Start (Actual): March 19, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): July 17, 2028

Study Registration Dates

• First Submitted: December 14, 2025
• First Submitted That Met QC Criteria: December 22, 2025
• First Posted (Actual): December 24, 2025

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 29, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: CLIO-8221-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No