Multiple myeloma is the second most common blood cancer in the United States, with more than 32,000 new cases predicted in 2020. Unfortunately, many patients with this type of blood cancer eventually develop resistance to multiple types of treatments. This phenomenon is partially due to the fact that cancer stem cells, which have the ability to evade traditional therapies and then self-renew, help drive the disease.
It is for this reason that a team of researchers, at the UC San Diego School of Medicine and Ionis Pharmaceuticals, are developing a therapy that can destroy these malignant stem cells, thereby preventing the cancer from coming back. With support from CIRM, the team developed an approach that interacts with IRF4, a gene that allows myeloma stem cells and tumor cells to grow and survive chemotherapy and radiation. They have engineered an oligonucleotide, a short DNA molecule, to prevent IRF4 from functioning. The therapy, known as ION251, lowered disease burden, reduced the amount of myeloma stem cells, and increased survival when tested in mice bearing human myeloma. These results have enabled the team to start a Phase I clinical trial to see if this approach is safe and effective in people with myeloma.
To study the disease and test ION251, the team transplanted human myeloma cells into mice that lack an immune system and thus won’t reject human cells. Ten mice received the ION251 treatment and an additional ten mice received a control treatment. After receiving the ION251 therapy, the treated mice had significantly fewer myeloma cells after two to six weeks of treatment. Additionally, 70 to 100 percent of the treated mice survived, whereas none of the untreated control mice did.
In a news release from UC San Diego Health, Dr. Leslie Crews, co-senior author and assistant professor at the UCSD School of Medicine, elaborated on the promising results from the mouse study.
“The results of these preclinical studies were so striking that half the microscopy images we took to compare bone marrow samples between treated and untreated mice kept coming back blank — in the treated mice, we couldn’t find any myeloma cells left for us to study. It makes the science more difficult, but it gives me hope for patients.”
The Phase I clinical trial to assess the safety of ION251, sponsored by Ionis Pharmaceuticals, is now recruiting participants at Moores Cancer Center at UC San Diego Health and elsewhere. More information on this can be viewed by clicking the link here.
The full results of this study were published in the journal Cell Stem Cell.
The Stem Cellar 
Investigation showed that IRFA gene allow myeloma stem cells and tumor cells to grow and survive in chemotherapy and radiation. The study has been conducted in mice by using an engineered short oligonucleotide of DNA to prevent IRFA from functioning. The engineered DNA has been named as ION 251. Result of investigation showed that mice harboured with myeloma tumor were significantly eradicated by ION 251 after 2-6 weeks of treatment. However, fewer myeloma cells were determined in mice and improved 70-100% of survival rates in mice.
Most of the current cancer treatments do not completely eradicate the tumor cells in human body. A small number of cancer cells escaped from ION 251 treatment were left behind in the body and potentially transformed into IRFA-independent myeloma cells. Tumor cells are heterogeneous, they do not have stability in their genetic levels. They always change their genotype and phenotype to become more aggressive, invasive or metastatic. Cancer patients often become relapse after certain period of treatment. Therefore, the current cancer treatments do not completely cure the disease but only prolong survivor rate of patients.