Classic Hairy-Cell Leukemia at Relapse After Initial Purine Nucleoside Analog Therapy
This protocol addresses classic hairy-cell leukemia (HCL) requiring treatment at relapse, in a patient with no active infection and no renal impairment, after a prior purine nucleoside analog regimen did not maintain the target response.
Clinical Scenario
Classic hairy-cell leukemia requiring re-treatment, in the absence of active infection and without renal impairment. The patient has relapsed following an initial standard purine nucleoside analog regimen.
Previous Treatment — Goals Not Sustained
The prior line was a standard purine nucleoside analog regimen (cladribine or pentostatin). It aimed to achieve the following targets, which were not durably maintained and trigger escalation to this protocol:
- Near normalization of peripheral blood counts: hemoglobin >11 g/dL (without transfusion); platelets >100,000/mL; absolute neutrophil count >1,500/mL
- Regression of splenomegaly on physical examination
- Absence of morphologic evidence of HCL on peripheral blood smear and bone marrow, assessed by 6 months
Re-Treatment Approach (Partial Overview)
Re-treatment strategy at relapse is stratified by the duration of the previous remission. Options may involve re-use of purine analog therapy — potentially in combination with a monoclonal antibody agent — a clinical trial, or a shift to alternative and investigational approaches. The specific path taken depends on how long the prior remission lasted.
The full decision algorithm, selection criteria, and clinical-trial options are available in the complete protocol →
References
- In the absence of renal impairment or active infection, therapy should consist of a standard regimen of a purine nucleoside analog (either cladribine or pentostatin).
- If previous remission was >60 months, consider re-treatment with initial therapy.
- If previous remission was >24 months, then consider re-treatment with a purine analog possibly combined with an anti-CD20 monoclonal antibody, or a clinical trial.
- If previous remission was <24 months, consider alternative therapy, including investigational agents, after confirming accuracy of diagnosis.
- Older therapeutic approaches may still offer benefit (eg, interferon alpha, splenectomy, rituximab).
- Patients in complete response should have near normalization of peripheral blood counts: hemoglobin >11 g/dL (without transfusion), platelets >100,000/mL, and an absolute neutrophil count >1,500/mL.
- There should be regression of splenomegaly by physical examination.
DOI: 10.1182/blood-2016-01-689422
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