NCT06888323

Brief Summary

This phase I trial tests the safety, side effects and best dose of lintuzumab-ac225 for the treatment of patients with high risk myelodysplastic syndrome that has not responded to previous treatment (refractory). Lintuzumab-ac225 is a monoclonal antibody, called lintuzumab, linked to a radioactive agent called Ac225. Lintuzumab attaches to CD33 positive cancer cells in a targeted way and delivers Ac225 to kill them. Giving lintuzumab-ac225 may be safe, tolerable and/or effective in treating patients with high risk, refractory myelodysplastic syndrome.

Trial Health

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Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Trial recruitment is currently suspended
Enrollment
30

participants targeted

Target at P25-P50 for phase_1

Timeline
20mo left

Started Apr 2026

Geographic Reach
1 country

1 active site

Status
suspended

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress2%
Apr 2026Dec 2027

First Submitted

Initial submission to the registry

March 20, 2025

Completed
1 day until next milestone

First Posted

Study publicly available on registry

March 21, 2025

Completed
1.1 years until next milestone

Study Start

First participant enrolled

April 27, 2026

Completed
1.7 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 31, 2027

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 31, 2027

Last Updated

April 13, 2026

Status Verified

December 1, 2025

Enrollment Period

1.7 years

First QC Date

March 20, 2025

Last Update Submit

April 9, 2026

Conditions

Outcome Measures

Primary Outcomes (1)

  • Maximum tolerated dose

    Up to 70 days from first dose of lintuzumab-ac225

Secondary Outcomes (6)

  • Complete remission rate

    Up to 90 days after completion of treatment

  • Overall response rate

    Up to 90 days after completion of treatment

  • Progression free survival

    Up to 90 days after completion of treatment

  • Overall survival

    Up to 90 days after completion of treatment

  • Transcriptomic changes

    At baseline and after cycle 2 (cycles = 28 days)

  • +1 more secondary outcomes

Study Arms (1)

Treatment (lintuzumab-ac225)

EXPERIMENTAL

Patients receive lintuzumab-ac225 IV, over 30 minutes, on day 1 of each cycle. Cycles repeat every 28 days for 4 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo SPECT/CT scans and buccal swab on study, as well as bone marrow aspiration throughout the trial.

Radiation: Actinium Ac 225 LintuzumabProcedure: Bone Marrow AspirationProcedure: Buccal SwabProcedure: Computed TomographyProcedure: Single Photon Emission Computed Tomography

Interventions

Undergo bone marrow aspiration

Treatment (lintuzumab-ac225)

Given IV

Also known as: 225Ac-HuM195, Actimab-A, Actinium (225Ac) Lintuzumab Satetraxetan, Actinium-225-Labeled Humanized Anti-CD33 Monoclonal Antibody HuM195, LINTUZUMAB SATETRAXETAN AC-225, SGN-33 AC-225
Treatment (lintuzumab-ac225)
Buccal SwabPROCEDURE

Undergo buccal swab

Also known as: Buccal Scraping, Buccal Smear, Buccal swab/scraping, Buccal Swabbing
Treatment (lintuzumab-ac225)

Undergo SPECT/CT

Also known as: CAT, CAT Scan, Computed Axial Tomography, Computerized Axial Tomography, Computerized axial tomography (procedure), Computerized Tomography, Computerized Tomography (CT) scan, CT, CT Scan, Diagnostic CAT Scan, Diagnostic CAT Scan Service Type, tomography
Treatment (lintuzumab-ac225)

Undergo SPECT/CT

Also known as: Medical Imaging, Single Photon Emission Computed Tomography, Single Photon Emission Tomography, Single-Photon Emission Computed, single-photon emission computed tomography, SPECT, SPECT imaging, SPECT SCAN, SPET, ST, tomography, emission computed, single photon, Tomography, Emission-Computed, Single-Photon
Treatment (lintuzumab-ac225)

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Patients must have histologically or cytologically confirmed diagnosis of MDS by bone marrow biopsy by World Health Organization (2016) guidelines
  • Patients with MDS who have progressed or had no response after 6 cycles of azacitidine or 4 cycles of decitabine
  • For the expansion phase, we will be enrolling 12 more patients at the maximum tolerated dose: 6 patients with prior azacitidine or decitabine treatment and 6 patients with prior treatment with azacitidine or decitabine in combination with venetoclax
  • Patients with MDS must have ≥ 5% myeloblasts
  • Patients with demonstration of CD33 positive myeloblasts on flow cytometry using Phycoerythrin (PE) labeled anti-CD33 antibody, done as standard of care testing by every participating site
  • Age ≥ 18 years. Because no dosing or adverse event data are currently available on the use of lintuzumab-Ac225 in patients \< 18 years of age, children are excluded from this study
  • Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 (Karnofsky ≥ 60%)
  • Serum direct bilirubin ≤ 1.5 × institutional upper limit of normal (ULN)
  • Aspartate aminotransferase (AST)(serum glutamic oxaloacetic transaminase \[SGOT\])/ alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase \[SGPT\]) ≤ 3 × institutional ULN
  • Creatinine clearance ≥ 50mL/min (Cockcroft-Gault equation)
  • HIV-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial
  • For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated
  • Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load
  • Patients with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, patients should be class II or better
  • The effects of lintuzumab-Ac225 on the developing human fetus are unknown. For this reason and because CD33 radiotherapy agents are known to be teratogenic, female patients of childbearing age must have had a negative serum pregnancy test within 14 days of initiation of dosing and must agree to use of two acceptable methods of birth control while on the study drug. A woman must agree to remain on a highly effective method throughout the study and for at least 6 months after the last dose of study drug. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. During the study and for 30 days after receiving the last dose of study drug in addition to the highly effective method of contraception, a man (a) who is sexually active with a woman of childbearing potential must agree to use a barrier method of contraception (e.g. condom with spermicidal foam/gel/film/cream/suppository); (b) who is sexually active with a woman who is pregnant must use a condom; (c) must agree not to donate sperm
  • +1 more criteria

You may not qualify if:

  • Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial
  • Patients have active clinically significant graft vs. host disease (GVHD) or are on systemic corticosteroids
  • Patients have clinically active central nervous system (CNS) leukemia
  • Patients who are receiving any other investigational agents, such as experimental treatment in a clinical trial within the last 30 days or 5 half-lives, whichever is shorter, prior to enrollment, or is currently enrolled in any other type of medical research (e.g. medical device) not scientifically or medically compatible with this study
  • Patients who are receiving any therapy that can result in increased toxicity on this study or confound the study findings, within the last 30 days or 5 half-lives, whichever is shorter, prior to enrollment
  • History of allergic reactions attributed to compounds of similar chemical or biologic composition to lintuzumab-Ac225
  • Patients with uncontrolled intercurrent illness or any other significant condition(s) that would make this protocol unreasonably hazardous
  • Pregnant women are excluded from this study because lintuzumab-Ac225 is a CD33 radiotherapy agent with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with lintuzumab-Ac225, breastfeeding should be discontinued if the mother is treated with lintuzumab-Ac225
  • The patient had major surgery within 14 days prior to enrollment
  • No prior radiopharmaceutical therapy and no radiation therapy within the last 120 days prior to cycle 1 day 1 (C1D1), as this may contribute to added toxicity
  • Patients who are unable to take spironolactone or eplerenone due to intolerance, allergy, drug-drug interactions, or for any other reason

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Dana-Farber - Harvard Cancer Center LAO

Boston, Massachusetts, 02115, United States

Location

MeSH Terms

Conditions

Myelodysplastic Syndromes

Interventions

ActiniumX-RaysPhotons

Condition Hierarchy (Ancestors)

Bone Marrow DiseasesHematologic DiseasesHemic and Lymphatic Diseases

Intervention Hierarchy (Ancestors)

Actinoid Series ElementsElements, RadioactiveElementsInorganic ChemicalsMetals, HeavyRadioisotopesIsotopesMetalsElectromagnetic RadiationElectromagnetic PhenomenaMagnetic PhenomenaPhysical PhenomenaRadiationRadiation, IonizingElementary ParticlesLightOptical PhenomenaRadiation, Nonionizing

Study Officials

  • Talha Badar

    Dana-Farber - Harvard Cancer Center LAO

    PRINCIPAL INVESTIGATOR

Study Design

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

Study Record Dates

First Submitted

March 20, 2025

First Posted

March 21, 2025

Study Start

April 27, 2026

Primary Completion (Estimated)

December 31, 2027

Study Completion (Estimated)

December 31, 2027

Last Updated

April 13, 2026

Record last verified: 2025-12

Data Sharing

IPD Sharing
Will share

NCI is committed to sharing data in accordance with NIH policy. For more details on how clinical trial data is shared, access the link to the NIH data sharing policy page.

More information

Locations