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Completed Phase 1Phase 2 Interventional Results available

Anti-Tac for Treatment of Leukemia

ClinicalTrials.gov ID: NCT00001941

Public ClinicalTrials.gov record NCT00001941. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 6, 2026, 5:49 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Official title

A Phase I/II Study of the Efficacy and Toxicity of Humanized Anti-Tac (Zenapax(Trademark)) in the Therapy of Tac-Expressing Adult T-Cell Leukemia

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

The purpose of the study was to determine: (1) the toxicity and maximum tolerated dose (MTD) of humanized anti-Tac (daclizumab), (Zenapax(Registered Trademark)) in patients with adult T-cell leukemia/lymphoma (ATL); (2) to define the dose of Zenapax(Registered Trademark) required to saturate interleukin 2 receptor alpha (IL-2R) alpha in patients with ATL; (3) determine the clinical response to humanized (Hu) anti-Tac (Zenapax(Registered Trademark) of patients with Tac-expressing adult T-cell leukemia; and (4) determine the serum dieaway curve (pharmacokinetics) of infused humanized (Hu)-anti-Tac in patients who have ATL. This study represented an extension of Metabolism Branch National Cancer Institute (NCI) protocols utilizing modifications of the original murine anti-Tac monoclonal antibody (mAb) developed by our group for the treatment of ATL. The scientific basis for these therapeutic studies is that the leukemic cells of patients with ATL express abnormally high levels of the Tac antigen (IL-2R alpha) on their surface whereas resting normal cells including normal T-cells of the patients do not. One presumed mode of action of Hu-anti-Tac in the treatment of ATL involves the interruption of the interaction of interleukin 2 (IL-2) with its growth factor receptor. To be effective in this goal we must maintain saturation of the IL-2 receptors (IL-2R) with humanized anti-Tac thereby preventing IL-2 mediated proliferation and yielding cytokine deprivation and apoptotic cell death of the leukemic cells. Eligible patients with ATL were treated with escalating doses of Zenapax(Registered Trademark) between groups in the Clinical Center of the National Institutes of Health (NIH). Groups of patients received sufficient Zenapax(Registered Trademark) to yield saturation of the IL-2 receptor for a period of 17 weeks. Clinical response was evaluated using routine immunological and clinical evaluation and by monitoring the saturation of the IL-2R and the absolute number of residual circulating malignant cells by fluorescence activated cell sorting (FACS) analysis using two fluorochrome-labeled non-crossreacting antibodies to the IL-2 receptor, anti-Tac and 7G7/B6, as well as antibodies to cluster of differentiation 3 (CD3), cluster of differentiation 4 (CD4), cluster of differentiation 7 (CD7), and cluster of differentiation 8 (CD8). Furthermore, responses were evaluated in patients with leukemia by Southern blot analysis of the arrangement of the T-cell receptor genes and human T-lymphotropic virus type 1 (HTLV-I) integration. Finally, in select patients, to define the pharmacokinetics of the therapeutic antibody, had planned to monitor the serum levels of the infused Hu-anti-Tac (Zenapax(Registered Trademark)) as a function of time. This study is an essential element of our program involving IL-2R-directed therapeutic studies. If as anticipated the therapy with humanized anti-Tac yields some partial and complete remissions in patients with ATL, we will propose that it be used as a single agent for patients with smoldering and chronic ATL and in association with chemotherapeutic agents to provide a novel approach for the treatment of acute and lymphoma forms of ATL. We also plan a future clinical trial where tentative plans also had been made to evaluate the efficacy and toxicity in ATL patients of saturating doses of Zenapax(Registered Trademark) as compared to identical doses of Zenapax(Registered Trademark) given in association with (90)Y-armed 7G7/B6, a non-competing antibody to IL-2R alpha or in combination with chemotherapy.

Study identification

NCT ID
NCT00001941
Recruitment status
Completed
Study type
Interventional
Phase
Phase 1, Phase 2
Enrollment
34 participants

Conditions and interventions

Interventions

Biological

Eligibility (public fields only)

Age range
10 Years and older
Sex
All
Healthy volunteers
Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Nov 30, 1999
Primary completion
Jan 31, 2011
Completion
Jan 31, 2011
Last update posted
Aug 19, 2012

1999 – 2011

United States locations

U.S. sites
1
U.S. states
1
U.S. cities
1
Facility City State ZIP Site status
National Institutes of Health Clinical Center, 9000 Rockville Pike Bethesda Maryland 20892

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT00001941, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Aug 19, 2012 · Synced Sep 6, 2026

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The complete protocol, eligibility criteria, and contact information for NCT00001941 live on ClinicalTrials.gov.

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