Researchers at University of California San Diego School of Medicine have found that treatment with cirmtuzumab, an experimental monoclonal antibody-based drug effective and safe in Phase I clinical trial. The findings are published in the June 1 issue of Cell Stem Cell.
In this trial, the research team treated 26 patients with relapsed CLL with increasing amounts of cirmtuzumab, which was found exceptionally well-tolerated. Patients received only a short-course of treatment and this appeared to halt disease progression, allowing most patients to forego any additional therapy for more than eight months. This is noteworthy as the patients who enrolled in the trial had leukemia that was getting worse and causing disruption of normal blood production or other clinical problems.
CLL is the most common form of blood cancer in adults, resulting in a progressive and deadly overabundance of white blood cells, called lymphocytes. CLL accounts for roughly one quarter of new cases of leukemia (21,000) annually and roughly 4,500 deaths each year.
Cirmtuzumab targets a molecule called ROR1 that normally is used only by embryonic cells during early development, but which is abnormally exploited by cancer cells to promote tumor growth and spread, otherwise known as metastasis. Metastasis is responsible for 90 percent of all cancer-related deaths.
Additional clinical studies of cirmtuzumab are ongoing or planned. Earlier this year, UC San Diego researchers launched a phase Ib/II clinical trial to evaluate the combined effectiveness of a standard of care drug called ibrutinib (marketed as Imbruvica) with cirmtuzumab to B-cell malignancies, which include leukemias and lymphomas.