Sandbox: HCL therapy

Overview

There is no curative treatment for hairy cell leukemia. The mainstay of therapy for hairy cell leukemia patients is chemotherapy. Pharmacological agents used for the treatment of hairy cell leukemia patients include cladribine, pentostatin, rituximab, and vemurafenib.

Medical Therapy

• There is no curative treatment for hairy cell leukemia.
• The mainstay of therapy for hairy cell leukemia patients is chemotherapy.
• Asymptomatic hairy cell leukemia patients, with no indications for therapy, may be managed by observation and close follow-up.
• Indications to initiate medical therapy among patients with hairy cell leukemia include:

• The presence of systemic symptoms such as fever, night sweats, and significant weight loss
• The presence of subcostal abdominal discomfort due to splenomegaly
• A positive history of recurrent infections
• Hemoglobin concentration lower than 12 g/dl
• Platelets count lower than 100,000/mcl
• Absolute neutrophils count lower than 1000/mcl

• Pharmacological agents used for the treatment of hairy cell leukemia patients include:

• Cladribine
• Pentostatin
• Rituximab
• Interferon alpha
• Vemurafenib

First Line Therapy

• The preferred pharmacological agent used for the initial management of hairy cell leukemia could be either cladribine or pentostatin.
• Cladribine is administered by a single daily IV infusion for a period of 5-7 days.
• Pentostatin is administered by a single IV infusion every 2 weeks for a period of 3-6 months.
• Common side effects of such agents may include:

• Immune suppression
• Acute kidney failure
• Fatigue
• High fever

• Hairy cell leukemia patients who demonstrate a complete response following initial medical therapy should be followed-up with close observation for any signs of relapse.
• A complete response to medical therapy among patients with hairy cell leukemia is defined by:

• Resolution of the patient's symptoms
• The absence of splenomegaly on physical exam
• Recovery of the patients blood counts to the normal limits
• The absence of malignant leukemic cells on blood smear or bone marrow aspiration

Relapsed Therapy

• The optimal therapy for patients who relapse after a complete response depends on the duration of disease-free period following the initial medical therapy.
• Hairy cell leukemia patients who relapse after one year or more are be managed by the same initial purine analogue ± rituximab.
• Whereas hairy cell leukemia patients who relapse before a period of one year are managed by an alternative purine analogue ± rituximab.

Refractory Therapy

• Hairy cell leukemia patients who do not demonstrate a complete response to medical therapy could be further managed by any of the following agents:

• Rituximab alone
• Interferon alpha alone
• An alternate purine analogue ± rituximab

• Rituximab is administered by a single IV infusion every week for a period of 8 weeks.
• Interferon alpha is administered subcutaneously (3 million units) three times a week for a period of 12-18 months.
• The major side effect of rituximab treatment is serum sickness, whereas the major side effects of interferon alpha are flu-like symptoms and depression.
• Patients with progressive hairy cell leukemia who do not demonstrate a complete response to any of the aforementioned medical therapies should be managed with a BRAF kinase inhibitor, such as vemurafenib.