Treatments For Mantle Cell Lymphoma
Mantle cell lymphoma is a type of non-hodgkins lymphoma that affects the lymphocytes in the “mantle zone” of the lymphnodes. This type of lymphoma accounts for 6% of all non-hodgkins lymphoma.
At present, first line therapy for mantle cell lymphoma is still a combination of chemoimmunotherapy (CHOP-rituxan, etc.) but currently several targeted agents have been approved as monotherapies in relapsed disease.
Velcade (bortezomib) was the first agent FDA approved as second line therapy; it is a proteasome inhibitor which blocks the breakdown of proteins in the cell resulting in a buildup of proteins leading to cell death. Velcade is administered intravenously or subcutaneously. This drug can cause myelosuppression and diarrhea but the most significant side effect is peripheral neuropathy. The side effects are milder if given subcutaneously.
In June of 2013, revlimid (lenalidomide) was FDA approved for relapsed mantle cell lymphoma, an oral drug, initially approved for myeloma. Revlimid is a derivative of thalidomide although much more powerful and less toxic with immunomodulatory and antiangiogenic properties. The population tested was heavily pre-treated and it still yielded a response rate of 26% with a complete response of 7%. Bone marrow suppression, rash, and diarrhea were the most common side effects; in general the drug was very well tolerated.
In November of 2013, another oral agent, imbruvica (ibrutinib) was FDA approved in relapsed mangle cell lymphoma. Ibrutinib is a targeted agent that blocks the BTK enzyme ultimately causing cell death. Used as monotherapy it yielded a 65% partial or complete response. Approximately 20% of patients develop side effects ranging from myelosuppression, rash, fatigue, infections, and shortness of breath, edema, and anorexia. This treatment cannot be given to patients with liver problems.
These new targeted agents have mechanisms of action completely different from chemotherapeutic agents, making them orally available and with a lower toxicity profile. Hopefully in the near future targeted agents will be available as front line therapy making chemotherapy a treatment of the past.