Clinical trial NCT00314093
Conditions: Metastatic Melanoma
Keywords: Clinical Response Stage IV Melanoma Immunotoxin T Regulatory Cells CD25+ Cells Metastatic Melanoma
Sponsor: University of Texas Southwestern Medical Center
Start date: 2006-04-01; Completion date: 2008-11-01
Enrollment: 41 participants; Allocation: NA; Intervention model: SINGLE_GROUP

Brief summary:
Background:

* CD4+ cells are white blood cells that regulate the immune system by controlling the strength and quality of the immune response.
* CD25+ cells are a subset of CD4+ cells that suppress or prevent immune responses.
* RFT-5-dgA is an immunotoxin (substance that kills specific cells in the immune system) that kills CD25+ cells.
* In mouse studies, RFT-5-dgA showed anti-tumor activity in animals studies.

Objective: To determine whether the immune system of patients with metastatic melanoma (melanoma that has spread beyond the original site) can cause tumors to shrink if the patients are given RFT-5-dgA to remove their CD25+ cells.

Eligibility: Patients 18 years of age and older with metastatic melanoma whose disease has progressed after receiving standard treatment.

Design:

* Patients receive RFT-5-dgA through a vein every other day for a total of 3 doses (one treatment course). Patients have routine blood tests during the week of treatment.
* Four to 5 weeks after the last dose, patients are evaluated with a physical examination, blood tests and scans and x-rays to evaluate their tumor.
* Patients whose tumor has shrunk or remained stable may be offered additional treatment with RFT-5-dgA up to a total of four courses.
* Patients undergo leukapheresis or have several tubes of blood drawn from a vein to determine the effects of RFT-5-dgA on the immune system. This is done before the first dose of RFT-5-dgA, after the first three doses, and possibly during subsequent treatment courses in those patients who receive additional treatment. For leukapheresis, blood is collected through a needle in an arm vein and flows through a catheter into a machine that separates it into its components by spinning. The white cells are extracted and the rest of the blood is returned through another needle in the other arm.

Detailed description:
Background:

* RFT5-dgA is an immunotoxin comprised of the IL-2Ra-specific murine IgG1 antibody RFT5 linked to deglycosylated ricin A chain (dgA) via the sterically hindered heterobifunctional disulfide linker SMPT (4-succinimidyl-oxycarbonyl-a-methyl-a-(2-pyridyldithio)-toluene).
* RFT5-dgA is a recombinant immunotoxin that selectively targets CD25 expressing cells in vivo. Further, treatment of human PBMC with RFT5-dgA in vitro results in the preferential depletion of CD25+ Treg cells.
* Depletion of Treg cells can enhance tumor protection to tumor-associated antigens expressed as self antigens and the RFT5-dgA immunotoxin had potent antitumor effects in SCID mice xenografted with L540 cells which express CD25.
* The MTD established in the phase I trial of RFT5-dgA was 15mg/m(2)/course IV.

Objectives:

* The primary objective is to determine whether objective clinical responses can be obtained in patients with metastatic melanoma following administration of RFT5-dgA.
* Secondary objectives will determine whether changes occur in levels of CD4+CD25+ regulatory T cells (Treg cells) in peripheral blood from before to after treatment and evaluate the toxicity profile of patients treated on this trial.

Eligibility:

* Patients greater than 18 years of age with measurable metastatic melanoma, an expected survival greater than three months, who have progressed after receiving standard therapy will be included.
* Standard clinical laboratory values must be normal for study inclusion and patients may not be pregnant, breast-feeding or require anticoagulation.
* Patients must be willing to undergo leukapheresis.
* Patients with active infections, other major medical disorders, HAMA levels greater than 1 ug/mL, or who have had prior radiotherapy or who have extensive lung disease will be excluded.

Design:

* Patients will receive 3 mg/m(2) RFT5-dgA intravenously every other day for a total of 3 doses (one course).
* Four to five weeks after the last dose, patients will undergo tumor evaluation, evaluation of changes in T-regulatory cells (CD4+CD25+cells and Foxp3 expression), and toxicity assessment.
* One additional course may be administered to patients with stable disease or partial or complete response.
* Up to 41 evaluable patients may be accrued to determine whether theRFT5-dgA can produce a modest response rate targeted to be 20 percent (p1=0.20)
* Enrollment reflects the anticipated enrollment. Actual enrollment is unknown due to no longer having access to the data as records were destroyed

Interventions: intervention 1: RFT5pdgA
Intervention descriptions: intervention 1: None

Protocol documents: