WASHINGTONThe National Cancer Institute will expand its support for trials of imatinib(Drug information on imatinib) mesylate (Gleevec, also known as STI-571), recently approved for use in chronic myeloid leukemia (CML), to explore the drug’s potential in several other types of malignancies, director Richard D. Klausner, MD, told the National Cancer Advisory Board (NCAB).
Gleevec blocks the functioning of Bcr-Abl, an abnormal protein that results from a reciprocal translocation between chromosomes 9 and 12the Philadelphia chromosomeand causes CML. Im-atinib also inhibits c-kit and PDG-F, two additional proteins linked to a number of other cancers.
Three NCI-sponsored studies are currently enrolling patients. A phase III randomized trial is comparing two different imatinib doses in patients with CD117-expressed metastatic or unresectable gastrointestinal stromal tumor (GIST). Its protocol calls for enrolling 600 patients age 15 and older within 2 years.
At the American Society of Clinical Oncology (ASCO) meeting in May, Charles D. Blanke, MD, of the Oregon University Health Sciences Center, reported results from a phase II trial of 148 GIST patients treated with imatinib. The results showed an 85% tumor control rate: 59% partial response and 26% stable disease.
The second active imatinib trial is a phase I/II brain tumor study in patients age 18 and older. The study will enroll 36 patients with recurrent malignant glioma or meningioma in a phase I trial. The phase II trial will accrue between 40 and 60 glioma patients.
Finally, a phase I imatinib study is enrolling patients under age 22 with recurrent Ph-chromosome-positive leukemia (ALL, AML, CML).
NCI will also support three phase I/II studies that are approved but not yet active. One will determine the safety of imatinib combined with daunorubicin(Drug information on daunorubicin), vincristine, and prednisone(Drug information on prednisone) in patients age 18 and older with blastic-phase CML or Ph-chromosome-positive acute lymphocytic leukemia (ALL).
A second will test the maximum tolerated dose of interferon-alfa administered with imatinib in 15 to 40 patients age 18 and older with newly diagnosed or interferon refractory or resistant chronic phase CML. Researchers will also enroll up to 32 patients age 18 and older with blastic-phase CML in a study to determine the maximum tolerated dose of high-dose cytarabine(Drug information on cytarabine) combined with imatinib.
Protocol abstracts of the active and approved imatinib trials can be found at http://cnetdb.nci.nih.gov.