NEW YORK--Researchers at the National Cancer Institute are targeting
a T-cell interleukin-2 (IL-2) receptor in an attempt to find an
effective treatment for patients with adult T-cell leukemia/lymphoma
(ATL), Thomas A. Waldmann, MD, chief of the NCI's Metabolism Branch,
said at a symposium sponsored by the New York City-based Cancer
The targeted T-cell receptors under study are "promiscuous,"
he said; that is, they are shared by the interleukin superfamily
that includes IL-2, IL-4, IL-7, IL-9, and IL-15.
No Toxicity to Normal T Cells
The IL-2 receptor is not expressed in resting and activated normal
T cells, Dr. Waldmann noted, whereas it is highly expressed in
HTLV-1-associated ATL. Thus, tumor cells can be targeted with
a radionuclide-labeled monoclonal antibody (MoAb) without targeting
In an NCI trial of 19 ATL patients who were given unmodified mouse
antibody targeted to the IL-2 receptor, one third of the patients
underwent remission, including two who had a complete remission,
In a second trial, in which the MoAb was armed with yttrium-90
(90Y), nine of 18 patients with adult T-cell leukemia had a partial
or sustained complete remission.
A new trial is underway employing a humanized MoAb armed with
90Y. Use of the humanized product should allow repeat doses to
be given safely without development of immunogenicity.
Dr. Waldmann said that this therapeutic approach may also have
potential applications in cutaneous T-cell lymph-oma and in some
autoimmune disorders, as well as in the prevention of allograft