Hairy Cell Leukemia Treatment Protocols 

Updated: Dec 05, 2018
  • Author: Sandy D Kotiah, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Treatment Protocols

Treatment protocols for hairy cell leukemia (HCL) are provided below, including those for initial treatment, resistant disease, variant HCL, and relapsed/refractory HCL. [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

Symptoms requiring initiation of treatment

Many patients with HCL appear to be asymptomatic even after diagnosis, and about 10% will never require therapy. [13] Treatment should be initiated if the patient develops 1 or more of the following signs and symptoms:

  • Abdominal fullness or discomfort due to splenomegaly

  • Complaints of fatigue, weakness, and weight loss

  • Bruising and bleeding secondary to severe thrombocytopenia

  • Recurrent infections, which may be life-threatening, secondary to granulocytopenia and monocytopenia (absolute neutrophil count < 1000/µL; see the Absolute Neutrophil Count calculator)

  • Symptomatic anemia with a hemoglobin concentration < 11.0 g/dL

  • Vasculitis (rare)

Initial treatment recommendations

The purine analogues cladribine and pentostatin are first-line agents in the treatment of HCL. Cladribine is more commonly used because of ease of administration. [14]

  • Cladribine 0.1 mg/kg/day by continuous IV infusion for 7d (FDA approved) or  0.14 mg/kg/day IV or SC over 2h for 5d (different schedules but no apparent difference in toxicity; can use growth factors if febrile neutropenia) or

  • Pentostatin 4 mg/m2 IV bolus or over 30min every 2wk with 1.5 L of hydration for each dose for 3-6mo or

  • Interferon alfa 2b 2 million U/m2 SC 3 times per week for 12-18mo for relapsed or refractory HCL

  • Splenectomy (laparoscopic preferred) is considered for patients with bleeding from severe thrombocytopenia or failure to respond to systemic therapy; administer pneumococcal, meningococcal, and Haemophilusinfluenzae vaccines prior to surgery

Resistant disease

For patients who obtain no benefits from the use of a purine analogue, the use of an alternative analogue is recommended. In addition, the use of interferon alfa or a splenectomy may be an option.

Variant hairy cell leukemia

Variant hairy cell patients are resistant to the standard treatments, which include the use of purine analogues and interferon alfa. Combinations of rituximab and purine analogs are under evaluation. [13]

Relapsed/refractory disease

Patients may relapse after initial treatment, so it is important to retreat them with a second cycle of treatment that can lead to remission.

Although pentostatin and cladribine provide responses in greater than 85% of patients, and a median progression-free survival of up to 15 years, alternative treatments (eg, the addition of rituximab [14] ) are needed for patients whose disease becomes refractory to these treatments.

Moxetumomab pasudotox

Moxetumomab pasudotox is an anti-CD22 recombinant immunotoxin indicated for adults with relapsed or refractory hairy cell leukemia (HCL) who have received at least 2 prior systemic therapies, including a purine nucleoside analog. [15]

Dose: 0.04 mg/kg IV on days 1, 3, and 5 of each 28-day cycle; infuse over 30 minutes; continue for maximum of 6 cycles or until disease progression or unacceptable toxicity occurs.