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 fewer 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 fewer 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.
• 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 Food and Drug Administration (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.

Investigational Drugs

Tyrosine kinase inhibitors. Tyrosine kinase is a growth-stimulating protein. Tyrosine kinase inhibitor drugs block the cell signals that trigger cancer growth. Several tyrosine kinase inhibitors, including imatinib (Gleevec) and dastinib (Sprycel), have recently been approved for treating Philadelphia chromosome-positive ALL. However, because patients can develop resistance to these drugs, new tyrosine kinase inhibitors are being investigated. For example, nilotinib (AMN-107) is being studied for patients with Philadelphia chromosome positive ALL who are resistant to imatinib.

Transplantation Procedures for Acute Lymphocytic Leukemia

In order to administer high-dose chemotherapy for advanced cancer cases, stem cell transplantation procedures may be used. These procedures are based on removal and replacement of stem cells, which are produced in the bone marrow. Stem cells are the early forms for all blood cells in the body (including red, white, and immune cells). Cancer treatments harm growing cells as well as cancer cells, and so the healthy stem cells must be replaced by transplanting them from the donor into the patient.

Collecting the Stem Cells

Sources of Cells. Stem cells must first be collected either from:

• Bone marrow (bone marrow transplantation)
• Blood (peripheral blood stem cell transplantation)

Donor or Patient Cells. The sources of marrow or blood cells can be taken from the patient or a donor:

• If the bone marrow or stem cells are taken from a donor, the transplant is referred to as allogeneic. Allogeneic transplants from genetically matched sibling donors offer the best results in ALL. With new techniques, donor bone marrow from unrelated but immunologically similar donors is proving to work as well as those from matched siblings. This approach is still reserved for patients in second remission or beyond. Allogeneic transplant may also be a good treatment option for patients with Philadelphia chromosome-positive ALL who are resistant to imatinib (Gleevec).
• If the marrow or blood cells used are the patient's own, the transplant is called autologous. Autologous transplants in patients with ALL are generally not beneficial, since there is some danger that the cells used may contain tumor cells and the cancer can regrow. Treatment advances that reduce this risk, however, may make autologous transplantation feasible in patients without family donors.

The Blood Stem Cell Collection Procedure

• The donor is usually given a drug called granulocyte colony-stimulating factor, or G-CSF (filgrastim, lenograstim) to stimulate stem cell growth.
• The donor (or patient in an autologous procedure) then undergoes apheresis. With this process, the blood is withdrawn from one of the patient's veins and passed through a machine that filters out the white cells and platelets, which contain the stem cells. The blood is returned through another vein. The entire procedure takes 3 - 4 hours but needs to be repeated several times.
• The stem cells are then frozen.

The Transplant Procedure

• The patient is given high-dose chemotherapy with or without radiation -- a treatment known as conditioning. The point is to inactivate the immune system and to kill any residual malignant cells. Drugs used are typically cyclophosphamide, carmustine, and etoposide. Alternative conditioning includes radiation with drugs.
• A few days after treatment, the patient is rescued using the stored stem cells, which are administered through a vein. This may take several hours. Patients may experience fever, chills, hives, shortness of breath, or a fall in blood pressure during the procedure.
• The patient is kept in a protected environment to minimize infection, and the patient usually needs blood cell replacement and nutritional support.

Success Rates

Two- to 5-year survival rates after transplantation plus chemotherapy range from 40 - 80%. Certain patients with the Philadelphia chromosome, which carries a poor prognosis, may achieve significant success with an allogeneic bone marrow transplant from a closely matched related donor.

Side Effects and Complications

Common side effects include nausea, vomiting, fatigue, mouth sores, and loss of appetite.

Blood stem cell transplantation itself is fairly dangerous and has a small risk for death. When it was first used, transplantation procedures had 10 - 25% morality rates. Now, mortality rates are below 5%.

Potentially serious complications include:

Infection resulting from a weakened immune system is the most common side effect. Because the stem cell procedure is done more swiftly, the risk period is shorter than with bone marrow transplantation. The risk for infection is most critical during the first 6 weeks following the transplant, but it takes 6 - 12 months post-transplant for a patientâ ' s immune system to fully recover. Immune systems of patients with graft-versus-host disease can take even longer to function normally

Many patients develop severe herpes zoster virus infections (shingles) or have a recurrence of herpes simplex virus infections (cold sores and genital herpes). Pneumonia, cytomegalovirus, aspergillus (a type of fungus), and Pneumocystis jerovicii (a fungus) are among the most important life-threatening infections.

It is very important that patients take precautions to avoid post-transplant infections. (See Home Management section of this report.)

Graft-versus-host disease (GVHD) is a serious attack by the patient's immune system triggered by the donated new marrow in allogeneic transplants. To reduce the risk for GVHD, doctors remove some immune T cells from the donorâ ' s stem cells before the transplant. Researchers are investigating new techniques to refine this process of T cell depletion.

Acute GVHD occurs in 30 - 50% of allogeneic transplants, usually within 25 days. Its severity ranges from very mild symptoms to a life-threatening condition (more often in older patients). The first sign of acute GVHD is a rash, which typically develops on the palms of hands and soles of feet and can then spread to the rest of the body. Other symptoms may include nausea, vomiting, stomach cramps, diarrhea, loss of appetite and jaundice (yellowing of skin and eyes). To prevent acute GVHD, doctors give patients immune-suppressing drugs such as steroids, methotrexate, cyclosporine, tacrolimus, and monoclonal antibodies.

Chronic GVHD can develop 70 - 400 days after the allogeneic transplant. Initial symptoms include those of acute GVHD. Skin, eyes, and mouth can become dry and irritated, and mouth sores may develop. Chronic GVHD can also sometimes affect the esophagus, gastrointestinal tract and liver. Bacterial infections and chronic low-grade fever are common. Chronic GVHD is treated with similar medicines as acute GVHD.

Too much sun exposure can trigger GVHD. Be sure to always wear sunscreen (SPF 15 or higher) on areas of the skin that are exposed to the sun. Stay in the shade when you go outside.

Other potentially serious complications include:

• Bleeding because of reduced platelets (highest risk within the first 4 weeks); blood transfusions may be required
• Infertility
• Organ complications to the liver, heart, kidney, or lungs
• Failure of the transplant
• Muscle problems, including stiffness, cramps, and joint pain
• Frequent urination and bladder control problems
• Older patients should be screened for osteoporosis (thinning of bones) and hypothyroidism (underactive thyroid)