Dr. Pullarkat on Assessing for MRD in ALL

Vinod A. Pullarkat, MD, clinical professor of Hematology & Hematopoietic Cell Transplantation, and hematologist/oncologist, discusses the importance of assessing for minimal residual disease in acute lymphoblastic leukemia.

MRD is a term applied to disease that we can detect; however, it cannot be detected via regular morphology or usual flow cytometry, says Pullarkat. In order to detect MRD, certain techniques are required, such as specialized flow cytometry and PCR-based methods, which are a little more sensitive than flow cytometry. MRD is the single most important prognostic marker in ALL, he stresses.

The earlier a patient becomes MRD-negative, the better their outcome will be. When chemotherapy is applied to frontline treatment, most experts agree that if patients do not become MRD-negative within about 3 cycles of treatment, it is unlikely they will benefit from continued therapy, explains Pullarkat.

In contrast, if a patient comes MRD-negative really quickly after induction, that patient will likely have a good outcome with continued chemotherapy, and as such, that person is not someone that would go to transplant. If a patient is persistently MRD-positive after a full cycle of consolidation therapy, then that patient would be a candidate for stem cell transplant. One unresolved question, according to Pullarkat, is whether or not something should be done to make that patient MRD-negative before transplantation.