Acute Lymphocytic Leukemia

Acute Lymphocytic Leukemia

Acute lymphocytic leukemia (ALL), also referred to as acute lymphoblastic leukemia, starts in the cells that become lymphocytes, which are white blood cells that normally help protect people from infections. In ALL, the abnormal cells grow quickly and, if untreated, can spread rapidly from the blood and bone to other parts of the body and be life-threatening.

Classifying ALL

To classify ALL, your doctor may use the World Health Organization (WHO) classification system, which considers the results of morphology (shape and size of the cancer cells), flow cytometry (the process of identifying markers/proteins on a cell), cytogenetic tests (a process that looks at the number and structure of chromosomes that make up cancer cells), and other molecular lab tests that provide detailed information about the subtype of ALL.

Also considered are the type of lymphocyte (B-cell or T-cell, which are the two main types of lymphocyte) the leukemia comes from, and how mature these leukemia cells are.

The subtypes of ALL include the following:

  • Acute precursor B-cell (pre-B-cell) lymphoblastic leukemia
  • Acute T-cell (lymphoblastic) leukemia (T-cell ALL)
  • Burkitt acute lymphoblastic leukemia (B-ALL)
  • Ph-positive (Philadelphia positive) ALL

In about 4 of every 10 cases of B-cell ALL (B-ALL), an abnormal chromosome, known as the Philadelphia chromosome, is present. It results from an abnormal fusion of two genes, BCR and ABL, which produces the BCR-ABL protein, which then helps B-ALL cells grow and multiply at a much faster rate than normal white blood cells. It is important to test for the Philadelphia chromosome or the BCR-ABL gene fusion, as some treatments are more likely to be effective for this type of ALL.

Treating All

Because ALL progresses quickly, treatment is recommended soon after you have been diagnosed and consulted with a leukemia expert physician. The following types of treatment may be used alone or in combination.

Chemotherapy is typically the main treatment for ALL. Treatment is given in three phases, spanning approximately three years. The goal of the induction phase is to eliminate as many ALL cells as possible. The consolidation phase aims to destroy any remaining leukemia cells. The maintenance phase involves lower-dose treatments to prevent new leukemia cells from growing. Your doctor may prescribe a corticosteroid, which will also help to destroy the leukemia cells and reduce inflammation.

Targeted therapy is drug therapy that works against specific abnormal proteins inside the leukemia cells and includes tyrosine kinase inhibitors (TKIs). TKIs are used primarily to treat ALL that is Philadelphia chromosome-positive. Targeted therapy is often given in combination with chemotherapy. Resistance to targeted therapy is common in B-ALL, but more targeted therapies are being developed to target the BCR-ABL gene fusion in B-ALL.

Immunotherapy is approved in these forms:

  • Chimeric antigen receptor (CAR) T-cell therapy is the first gene therapy approved in the U.S. to treat children and young adults with B-ALL. Though serious side effects can occur from CAR T-cell therapy, it can induce a complete remission when other treatments have failed.
  • Monoclonal antibodies (mAbs) are artificial antibodies (proteins) designed to attack specific targets, such as proteins found on cancer cells.

Stem cell transplantation in the form of an allogeneic transplant may be an option to treat poor-prognosis, relapsed or refractory ALL.

Radiation therapy may be used to treat leukemia cells that have metastasized (spread) to other areas of the body, such as the fluid surrounding the brain and spine or to the testicles. When it is given to the brain or spinal cord, it is known as central nervous system (CNS) sanctuary therapy or CNS prophylaxis. 

Drug therapies for ALL

These therapies may be used alone or in combination.
asparaginase (Elspar)
asparaginase erwinia chrysanthemi (Erwinaze)
asparaginase erwinia chrysanthemi (recombinant)-rywn (Rylaze)
blinatumomab (Blincyto)
brexucabtagene autoleucel (Tecartus)
calaspargase pegol – mknl (Asparlas)
clofarabine (Clolar)
dasatinib (Sprycel)
doxorubicin hydrochloride (Adriamycin)
imatinib mesylate (Gleevec)
inotuzumab ozogamicin (Besponsa)
mercaptopurine (Purinethol, Purixan)
nelarabine (Arranon)
pegaspargase (Oncaspar)
ponatinib (Iclusig)
tisagenlecleucel (Kymriah)
vincristine (Oncovin)