ImmTher is currently being evaluated in a randomized phase II trial for the treatment of patients with newly diagnosed Ewing’s sarcoma. This trial is ongoing at two cancer centers: M.D. Anderson Cancer Center and Memorial Sloan Kettering Cancer Center in New York. Last year, ImmTher was designated as an Orphan Drug by the FDA for the treatment of the primary types of bone cancer, Ewing’s sarcoma and osteosarcoma.
The results of this study titled, "ImmTher, a lipophilic disaccharide derivative of muramyl dipeptide, up-regulates specific monocyte cytokine genes and activates monocyte-mediated tumoricidal activity," show that ImmTher stimulates the production of select body immune responses thought to kill tumor cells directly.
ImmTher is a novel muramyl dipeptide immunomodulator formulated in liposomes, stimulating the body’s own natural tumoricidal defenses. ImmTher is designed to rid the body of micrometastatic cancer cells that have evaded initial chemotherapy or surgery by activating monocytes. Monocytes are considered the first line of defense against systemic invasion by microbes and cancer cells. Monocytes (or macrophages) interact directly with cancer cells by engulfing them or by secreting factors that kill them.
In phase I testing in patients, ImmTher showed evidence of lung and colorectal tumor regression, in addition to inducing elevated levels of TNF-(alpha) and neopterin, both cytokine factors involved in tumor killing activity.
The new findings extend these observations to a clear demonstration that high level of cytokines including Interleukin-8, Interleukin-1(alpha), Interleukin (beta), TNF(alpha), and Interleukin-12 are up-regulated (or stimulated) by ImmTher.
According to Dr. Kleinerman, "ImmTher is different from other drugs in this class, because it distinctly up-regulates the genes for IL-12. We think that one mechanism whereby this drug might exert its action is through IL-12 promoted events which include inhibition of angiogenesis and stimulation of naive T-cells."
Uncovering the mechanism of such drugs may help identify new ways such drugs can be used clinically. Explained Dr. Kleinerman, "We were surprised that ImmTher had activity not only against human Ewing’s sarcoma cells, but also against cultured melanoma cells and osteosarcoma cell lines."
"These findings demonstrate and underline the potential for using ImmTher in this bone cancer and may indicate a broader utility for ImmTher in treating other metastatic cancers," stated Michael S. Rosen, President and CEO of Endorex.
According to the National Cancer Institute, bone tumors account for approximately 5 percent of all pediatric cancer. Ewing’s sarcoma is the second most common primary bone tumor in pediatric patients - accounting for 45 percent of bone cancers in U.S. caucasian children, but is rare in non-caucasian populations. Ewing’s sarcoma is a cancer that responds to initial chemotherapy and surgical intervention, but tumors recur in a majority of patients within a two-year period. Once tumors have recurred in the lungs and other sites, there are no effective therapies for these patients.