Acute Lymphocytic Leukemia - Treatment After Relapse

Treatment After Relapse

Between 50 - 70% of children and 40 - 50% of adults who achieve complete remission after initial therapy but then suffer a relapse may be able to go into a second complete remission.

Treatment for relapse after a first remission may be standard chemotherapy or experimental drugs, or more aggressive treatments such as stem cell transplants.

The decision depends on a number of factors:

• Children who relapse 3 or more years after achieving a first complete remission have an excellent chance for a second remission without aggressive treatments.
• Those who relapse less than 6 months following initial treatment, especially while on chemotherapy, have about a 20% chance of long-term freedom from disease. In such cases, remission is possible following another course of standard chemotherapy but the duration of remission is usually less than 6 months.

Treatment decisions also rely on prior treatments and where the relapse has occurred. Relapse can occur in the bone marrow, central nervous system, or sanctuary disease sites (brain, spine, or testicles). The incidence of relapse in sanctuary sites is about 10%.

Candidates for transplantation include:

• Patients who relapse following initial remission with standard chemotherapy.
• High-risk patients in first remission who are unlikely to be cured by standard chemotherapy alone. Many adult patients may fall into this category. Studies on high-risk children have been conflicting about the value of transplants during a first remission, with a 2000 study reporting no significant advantage. A 2001 study on children with the Philadelphia chromosome, however, suggested that this approach offered a better chance for a cure.
• Patients who fail to achieve a complete remission during initial chemotherapy.

Transplantation procedures do not appear to offer any additional advantages for patients at low or standard risk.

Chemotherapy Drugs Used After Relapse

Many different drugs are used to treat ALL relapses. These drugs include vincristine, asparaginase, anthracyclines (doxorubicin, daunorubicin), cyclophosphamide, cytarabine (ara-C), and epipodophyllotoxins (etoposide, teniposide). Corticosteroids, such as prednisone or dexamethasone, may also be used.

In 2004, the FDA approved clofarabine (Clolar) for treatment of relapsed or refractory ALL in children. This drug was the first new leukemia treatment approved specifically for young patients in more than a decade. In 2005, nelarabine (Arranon) was approved to treat adults and children with relapsed or refractory T-cell acute lymphocytic leukemia (T-ALL). In 2006, the FDA approved imatinib (Gleevec) for treating patients with Philadelphia chromosome-positive ALL that has not responded to or has returned after treatment. Also in 2006, the FDA approved dasatinib (Sprycel) for patients who are not helped by imatinib.