Acute lymphoblastic leukemia (ALL) is a rare blood cancer, which is challenging to treat because of its aggressiveness and rapid progress. 

Even if ALL patients reach complete response (CR) through chemotherapy, most experience recurrence. Many of these patients die within six months.

This is why it is absolutely crucial for ALL patients to receive minimal residual disease (MRD) treatment and keep the risk of relapse at low levels in advance. 

MDR means that leukemia cells remain in the body even though bone marrow examination on the treated patient shows normal levels. 

In the past, it was difficult to confirm the existence of MRD. However, as test techniques gradually developed, it became possible to detect whether or not the patient was MRD positive.

In general, about 40 percent of adult ALL patients who reached complete remission are MRD-positive. These patients have a higher risk of recurrence and a poor survival prognosis than MRD-negative patients.

MRD treatment affects the success rate of hematopoietic stem cell transplantation (HSCT). In order to get HSCT, an ALL patient must reach CR. MRD-positive patients have a lower success rate of HSCT than MRD-negative ones. In other words, it is difficult to expect a cure without MRD treatment in ALL patients.

The clinical usefulness of blinatumomab, sold under the brand name Blincyto, in MRD treatment has already been confirmed in several clinical studies. 

In the BLAST study, 78 percent of patients achieved a complete MRD treatment response with only one cycle of administration, and they had a longer relapse-free survival (RFS) and overall survival (OS) than patients who did not achieve a complete MRD treatment response

Based on this clinical usefulness of blinatumomab, the NCCN guidelines also recommend blinatumomab as the only treatment alternative for adult ALL patients with MRD or those whose MRD levels are increasing after primary CR.

With the growing importance of MRD treatment, advanced countries are accordingly building treatment strategies for ALL patients. 

For ALL patients who reached CR but are exposed to a serious risk of recurrence due to MRD, blinatumomab is the only opportunity to expect a full cure. 

With confirmed data through clinical trials, treatment guidelines based on this data, and treatment for MRD, I hope ALL patients could face the future with hope, not fear of recurrence.