Study Boosts The Effect Of Chemotherapy
A new study published in the journal Blood shows an innovative new treatment method that boosts the effect of chemotherapy in the treatment of acute myeloid leukemia. The new technique involves the use of a new drug that displaces the affected white blood cells from the bone marrow into the bloodstream, instead of directly attacking them. This new drug increases the effectiveness of chemotherapy.
Researchers from the Washington University, led by Dr. Geoffrey Uy, say that previous treatment schemes have proven useful for clearing the cancerous cells from the blood, but have also proven to be ineffective against cancerous cells that remained in the bone marrow.
Scientists conducted a 2-phase clinical trial on 52 patients with AML (Acute Myeloid Leukemia) that either suffered a relapse or their form of AML wasn’t responding to the treatment scheme. A number of 46 patients received the new drug. After the trial finished, data showed that 21 of the 46 patients (almost 46 percent) were completely cured, having all cancerous cells eradicated from both their bone marrow and their blood. Dr. Geoffrey Uy says that based on clinical data he had gathered from his own patients, only 25 percent of them were completely cured, adding that the results of standard chemotherapy were also dependent on individual characteristics.
Senior author of the study Dr. John DiPersio says that even though recent studies show that acute myeloid leukemia is caused by different genetic mutations in every patient, the increased survivability of the cancerous cells is also a result of the bone marrow’s protective effects.
Dr. DiPersio says that future studies will try to develop new therapies that instead of targeting the cancer itself, will target the environment of the bone marrow, thus effectively destroying the common pathways of the leukemic cancerous cells. He adds that targeting the cancer would probably be ineffective due to the fact that most of the mutations leading to the cancerous proliferation are unique for every patient.
The scientists that conducted this study agree that if the results they have obtained were to be reproduced on a larger scale it would completely change the standard therapy for patients with acute myeloid leukemia. Furthermore, the new approach of targeting the environment found in the bone marrow would aid the development of new treatment for other hematologic malignant tumors.
The leukemic cancerous cells from the bone marrow are protected from the effect of chemotherapy through the inhibiting effect that the bone marrow has on the normal cell-suicide response. The leukemic cells are also protected from drugs due to their own slow cellular division. A standard chemotherapy treatment is useful against the cells found in the bloodstream but some cells still remain in the bone marrow and can later cause a relapse.
The new drug, named plerixafor, has the effect of blocking the attachment of cancerous cells to the bone marrow, thus managing to release them into the bloodstream where they will be destroyed under the effect of chemotherapy.
The United States Food and Drug Administration has already given its approval for plerixafor in 2008 when it was being used, before the stem cell transplant technique appeared, to treat non-Hodgkin’s lymphoma and multiple myeloma. The drug was used to displace the normal stem cells from the bone marrow to the bloodstream, where the stem cells could be collected for a future transplant. After undergoing an aggressive chemotherapy treatment, patients would receive their healthy stem cells, as standard procedure.
“We helped in plerixafor's development for stem cell mobilization, so we thought if it makes normal stem cells leave the bone marrow to circulate, maybe it would do the same with leukemic cells”, said DiPersio.
Back in 2009, Dr. John DiPersio led a study on laboratory mice that suffered from acute myeloid leukemia. The results of the study showed that plerixafor, used with chemotherapy improved the survival rates of the tested mice. Dr. DiPersio says that their clinical trial is the first to show an improved effect of chemotherapy when used in combination with a drug that targets the environment of the bone marrow.