Acute Lymphocytic Leukemia Recurrent

Relapsed acute lymphocytic leukemia refers to the return of this blood cancer after previous treatment. While most people with ALL initially go into remission, between 15 and 20 percent of children and about 60 percent of adults experience a relapse, requiring additional treatment approaches.

Table of contents

• What is relapsed acute lymphocytic leukemia?
• When does relapse occur?
• Treatment approaches
• What to expect

What is relapsed acute lymphocytic leukemia?

Relapsed acute lymphoblastic leukemia, or relapsed ALL, refers to the return of acute lymphoblastic leukemia in patients who have already undergone treatment for the disease^[5]. Sometimes ALL can relapse, which means the ALL comes back after treatment^[13].

Relapse happens because some leukemia cells remain, often because they’ve become resistant to the drugs people are being treated with^[13]. As many as nine out of ten adults with ALL (90%) will go into remission initially, although this doesn’t necessarily mean that they’re cured^[13].

Refractory ALL is a related term that describes leukemia that did not respond to initial treatment. This means that the previous treatments did not kill enough leukemia cells (called blasts) to reach a complete remission^[10].

When does relapse occur?

Between 15 and 20 percent of children who are treated for ALL experience a relapse^[5][15]. The likelihood of relapse varies based on several factors, including when the disease returns and the person’s age.

Relapse can occur during different periods after initial treatment. If ALL relapses after a long remission, it may respond to the drugs used in the original treatment. However, if ALL relapses after a short remission, doctors will use other drugs. Around one-third of patients experience T-ALL relapse (return of the cancer) within one to two years^[9].

Treatment approaches

When a relapse occurs, the treatment approach depends on several factors, including the type of ALL, how long the remission lasted, and whether the cancer is B-cell or T-cell type.

Reinduction chemotherapy

Usually, the first step in treating relapsed ALL is to repeat the remission induction programme. This treatment might need to be more intense than the first time around^[13]. When chemotherapy is given for relapsed and refractory ALL, it is called reinduction chemotherapy^[10].

In trials, a second go at remission induction using chemotherapy has worked for around four out of ten people (40%)^[13]. Chemotherapy is the primary treatment for relapsed T-cell ALL, while immunotherapy is mainly used for relapsed B-cell ALL^[10].

Immunotherapy

Immunotherapy helps to strengthen or restore the immune system’s ability to fight cancer. It is often used for relapsed or refractory B-cell ALL^[10]. There are two new drugs called blinatumomab and inotuzumab which are available for relapsed ALL. These drugs are known as monoclonal antibodies — they work by attaching themselves to the leukemia cells, so the immune system can find these cells and kill them. They have shown promising results in clinical trials and tend to have fewer unpleasant side effects^[13].

The main type of immunotherapy used for ALL is CAR T-cell therapy. This treatment takes millions of T cells from a person with cancer. In the lab, they are changed so they have special receptors on their surface. These receptors recognize a specific protein found on the leukemia cells. The T cells are then given back to the person where they multiply, attack and destroy the leukemia cells^[10].

Tisagenlecleucel (Kymriah) is a CAR T-cell therapy approved to treat young adults (up to age 25) with B-cell ALL that has not responded to other treatment or has come back after a stem cell transplant or other treatments^[10]. For adult patients diagnosed with relapsed B cell-ALL (B-ALL), there have been significant improvements in available treatment options following approval of novel cellular and immunotherapy approaches^[11].

Stem cell transplant

A stem cell transplant replaces stem cells, which are found in bone marrow, blood and umbilical cords. They are basic cells that develop into different types of cells that have different jobs. For example, all our blood cells develop from blood stem cells^[10].

A stem cell transplant is a complex treatment with many risks, and it must be done in a special transplant centre or hospital. You may be offered a stem cell transplant after the leukemia relapses if another complete, or sometimes partial, remission is reached, or if the leukemia did not fully respond to treatment and only a partial remission was ever reached^[10].

If your treatment is successful and you go into remission, you may then have a stem cell transplant as part of your consolidation treatment^[13].

Clinical trials

If you do relapse you may be offered the opportunity to go on a clinical trial looking at new treatments for relapsed ALL^[13]. Your hospital team will talk to you about further treatment options, including clinical trials^[13].

What to expect

The outlook for relapsed ALL varies depending on many factors, including the type of ALL, the person’s age, and how long the initial remission lasted.

Treatment can cure up to 80% of children with relapsed T-cell ALL but typically less than 50% of adults^[9]. Around 75% of children and around 60% of adults with T-ALL remain cancer free after five and three years, respectively^[9].

The goal of treatment for relapsed or refractory ALL is to achieve another remission and potentially cure the disease. Treatment success depends on reaching remission quickly enough to allow for further treatments like stem cell transplant when appropriate.

• Bone marrow
• Blood
• Lymph nodes
• Spleen
• Liver
• Central nervous system (brain and spinal cord)