The role of rituximab in combination with pentostatin or cladribine for the treatment of recurrent/refractory hairy cell leukemia.
BACKGROUND
The purine analogs pentostatin and cladribine have revolutionized the treatment of hairy cell leukemia (HCL) with overall responses in greater than 85% of patients and a median progression-free survival of up to 15 years. They continue to be effective at second- and even third-line therapy; however, alternative treatments are needed for patients who are or have become refractory to these agents or whose remissions are shorter with each course of therapy.


METHODS
The authors conducted a retrospective review of 8 patients who received pentostatin or cladribine combined concurrently (n = 6 patients) or sequentially (n = 2 patients) with rituximab at second-line therapy (n = 3 patients) and at subsequent lines of therapy (n = 5 patients). Results from a previously reported database of 219 patients with HCL (73 patients who received second-line therapy and 20 patients who received third-line therapy) were used as a historic control group against which to measure benefit.


RESULTS
All 8 patients responded to therapy, with 7 complete responses (CRs) (87.5%) and minimal toxicity. All patients who had CRs were negative for minimal residual disease (MRD). At a median follow-up of 29 months (range, 5-39 months) 1 patient developed recurrent disease, and the estimated 2-year recurrence rate was 20% (0% after second-line therapy and 25% after subsequent lines of therapy). In the historic control group, the CR rates were 70% after second-line therapy and 45% after third-line therapy, and the recurrence rates at 2 years were 15% and 33%, respectively.


CONCLUSIONS
The combination of purine analogs with rituximab was safe and effective for patients with recurrent and/or refractory HCL, and the current results suggested an added benefit compared with standard treatment.
Else
Monica
M
Section of Haemato-Oncology, Royal Marsden Hospital/Institute of Cancer Research, Sutton, United Kingdom.
Osuji
Nnenna
N
Forconi
Francesco
F
Dearden
Claire
C
Del Giudice
Ilaria
I
Matutes
Estella
E
Wotherspoon
Andrew
A
Lauria
Francesco
F
Catovsky
Daniel
D
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D058846:Antibodies, Monoclonal, Murine-Derived; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D017338:Cladribine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007943:Leukemia, Hairy Cell / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D015649:Pentostatin / Q000008:administration & dosage; D012008:Recurrence; D000069283:Rituximab
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D015649:Pentostatin; D017338:Cladribine; D000069283:Rituximab