A new clinical trial at Baylor Scott & White Research Institute is exploring a novel treatment option for patients with multiple myeloma, a type of cancer formed in bone marrow plasma cells that is considered incurable.

The phase I trial will evaluate Actimab–M, developed by Actinium Pharmaceuticals, Inc., in treating patients with multiple myeloma who are unresponsive to available therapies. Actimab–M targets the CD–33 antigen commonly found on blood cells of myeloid lineage, both malignant and normal. The drug is an antibody that is bound to Actinium 225, a potent radioisotope. It delivers a focal dose of radiation to the target without affecting surrounding cells and tissues.

"Interestingly, we have found aberrant expression of this marker on some lymphoid cancers, including myeloma," said Yair Levy, MD, director of hematolgic malignancies research at Baylor University Medical Center at Dallas and principal investigator of the trial. "Research has shown its presence in cancer cells of 25 to 35 percent of all multiple myeloma patients, making it a possible target for treatment. In addition, it also predicts for a more aggressive course of disease."

In this new trial, Actimab–M will be used in patients whose myeloma expresses CD33, and who have progressing disease after at least three prior multiple myeloma therapies.

"Treatments for multiple myeloma have progressed tremendously in the past decade," Dr. Levy said. "Unfortunately most patients cancer recurs with current treatments and the disease is considered incurable at this time. We are examining the genetic behavior and tendencies of this cancer to hopefully identify new targets for treatment for these patients who experience disease progresses on our current therapies. This is the first trial in the U.S. to open using this method of treatment, taking bench research into the clinic."