Common brand names

• Campath

How it is administered

Alemtuzumab is administered as an intravenous (IV) infusion. For B-cell chronic lymphocytic leukemia (B-CLL), the recommended dosing involves gradually escalating to a maximum single dose of 30 mg, given three times per week for up to 12 weeks. The infusion should be administered over 2 hours, and premedication with an oral antihistamine and acetaminophen is recommended before each dose to reduce the risk of infusion-related reactions.

Alemtuzumab is supplied as a clear, colorless solution in a single-dose vial for IV use only. The medication must be diluted before administration and should not be given as an intravenous push or bolus.

How it works

Alemtuzumab is a monoclonal antibody that targets CD52, a protein found on the surface of B and T lymphocytes, most monocytes, macrophages, natural killer (NK) cells, and some granulocytes. By binding to CD52 on these cells, alemtuzumab triggers the immune system to destroy these cells through processes such as antibody-dependent cellular cytolysis and complement-mediated lysis.

In B-cell chronic lymphocytic leukemia (B-CLL), this action leads to the depletion of malignant B cells, as well as normal lymphocytes, which helps control the disease. The reduction of these immune cells can also result in immunosuppression, which is why infection risk is increased during and after treatment. The medication’s effects on lymphocyte populations are profound and can last for months after therapy, which is important for both its effectiveness and its side effect profile.

Who should take it

Alemtuzumab is indicated as a single agent for the treatment of B-cell chronic lymphocytic leukemia (B-CLL). It may be considered for patients with B-CLL who require therapy due to progressive disease. While specific data for B-cell prolymphocytic leukemia (B-PLL) is limited, alemtuzumab may sometimes be used off-label for other blood cancers that express CD52, under the guidance of a hematologist.

Patients who are candidates for alemtuzumab typically have not responded to, or are not suitable for, other standard therapies. The decision to use alemtuzumab should be made by a healthcare provider experienced in the treatment of blood cancers.

Who should not take it

Alemtuzumab should not be used in patients with active, serious infections. For the Campath formulation (used in blood cancers), there are no absolute contraindications listed in the FDA label, but caution is required in patients with severe cytopenias, autoimmune cytopenias, or bone marrow aplasia. Treatment should be withheld or discontinued if these conditions develop during therapy.

For the Lemtrada formulation (used in multiple sclerosis), alemtuzumab is contraindicated in patients with known hypersensitivity to the drug or its excipients, those infected with HIV, or those with active infections. Live viral vaccines should not be given to patients who have recently received alemtuzumab.

Commonly used with

Alemtuzumab is often used as a single agent in the treatment of B-CLL. However, patients are routinely given premedications such as antihistamines (e.g., diphenhydramine) and acetaminophen to reduce infusion reactions. Prophylactic antibiotics (such as trimethoprim/sulfamethoxazole for Pneumocystis jirovecii pneumonia) and antiviral agents (such as famciclovir for herpes virus) are recommended during treatment and for at least two months after completion, or until immune recovery.

Supportive care medications, such as granulocyte colony-stimulating factors, erythropoiesis-stimulating agents, or transfusions, may also be used to manage cytopenias.

Commonly tested with

Alemtuzumab has been compared to other chemotherapy agents such as chlorambucil in clinical studies for B-CLL. It is also sometimes studied in combination with other immunosuppressive or chemotherapeutic agents in clinical trials, but its primary use is as a single agent.

Routine laboratory monitoring with complete blood counts, CD4 counts, and infection surveillance (such as CMV PCR testing) is standard practice during and after alemtuzumab therapy.