Treatment of Hairy Cell Leukaemia with 2′-Deoxycoformycin

Revised guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant*

The British Committee for Standards in Haematology first produced guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant in 2000. This revision updates those guidelines and covers the areas of diagnosis, treatment and assessment of response to therapy.

Malignancy: Current Clinical Practice: Treatment of Hairy Cell Leukemia at the Close of the 20th Century

In the last half of this century, hairy cell leukemia was recognized as a distinct B-cell malignancy, accounting for 2% of all leukemias. Characteristics include splenomegaly, pancytopenia, a usually indolent course, and responsiveness to both interferon and purine analog therapy. Accurate diagnosis requires the demonstration of malignant cells in the bone marrow and peripheral blood which contain cytoplasmic projections and characteristic surface antigens. Splenectomy was identified early as a palliative therapy, and in 1984 systemic treatment with interferon alpha was first reported to induce complete remissions. Soon thereafter, the purine analog deoxycoformycin was found to induce more durable complete remissions in a higher percentage of patients. In 1990, 2-Chlorodeoxyadenosine, a new purine analog therapy, was reported to be capable of inducing long-term durable responses in most patients after a single cycle. Current challenges include identifying which purine analog is the least toxic since both appear similarly effective, and neither appear to add to the already increased rate of second malignancies occurring in these patients. Moreover, up to 25% of patients with hairy cell leukemia fail initially or eventually to respond to standard therapy, making the development of new approaches necessary. The characteristic bright expression of several B-cell antigens on the malignant cells, including CD20, CD22 and CD25, has led to the development of targeted biotherapeutic approaches. A recombinant immunotoxin targeting CD25 has recently been reported to induce major responses and it is likely that other successful targeted approaches will be reported early in the new century.

Purine analogs in the treatment of low-grade lymphomas and chronic lymphocytic leukemias

The purine analogs fludarabine (FAMP), 2-chlorodeoxy-adenosine (2-CDA) and 2-deoxycoformycin (DCF) comprise a novel group of agents with high activity in low-grade lymphoid malignancies. Although all three agents share several mechanisms of action, such as the induction of apoptosis, and toxic effects, such as prolonged immunosuppression, their activity appears to be different in different disorders. While FAMP and possibly also 2-CDA are highly active in chronic lymphocytic leukemia and low-grade follicular lymphomas, 2-CDA and DCF are most effective in hairy cell leukemia. However, prospective comparative evaluations are in progress and their results may ultimately help to define the appropriate indications for and potential side effects of these highly promising new agents.

Long term results of interferon treatment in hairy cell leukemia. Italian Cooperative Group of Hairy Cell Leukemia (ICGHCL)

Eighty nine of 104 patients with hairy cell leukemia (HCL), enrolled between 1985 and 1987 in a multicenter prospective study on human lymphoblastoid IFN alpha-n1, were evaluable for long-term follow-up. The induction treatment, 3 MU/mq daily for a median of 5.7 months, produced a response of 93%, complete+partial response (CR+PR) = 80%, minor (MR) = 13%. Neither prior splenectomy nor pre-treatment variables were associated with the rate of response to IFN. However maintenance treatment of 3 MU/mq weekly given randomly had a slightly significant effect on failure free survival (FFS). Of the 43 patients who relapsed, 31/36 (86%) obtained a new response with IFN. No differences in FFS were recorded between first and second response. At the third induction 7/11 patients were treated again with IFN, 4/7 obtaining some response, but the FFS was significantly worse. The overall survival is still 85%. We conclude that (1) IFN should be used as chronic uninterrupted treatment for HCL, (2) reduced dosage is sufficient to prolong the disease free status and (3) continuous lymphoblastoid IFN administration seems not to be associated with the development of resistance to retreatment.

Rapid restoration of natural killer activity following treatment with 2-chlorodeoxyadenosine in 22 patients with hairy-cell leukemia

We report on the T-cell profile and natural killer (NK) function in 22 hairy cell leukemia patients before and 2 and 6 months after a single 7-day course of 2-CdA therapy at a dose of 0.1 mg/kg daily continuous infusion. Before treatment, two groups of patients were identified in respect to NK activity: the first (12/22) had a normal number of T and NK cells and a normal NK activity, the second (10/22) showed a severe reduction of CD3+, CD4+, CD16+, and CD56+ cells, together with impaired NK activity. All patients had increased serum levels of the soluble interleukin 2 receptor (sIL-2R). Along with a high complete remission rate (77%), treatment with 2-CdA produced a significant reduction (p = 0.001) of total lymphocytes (from 1.59 x 10(9)/l to 0.72 x 10(9)/l), and particularly of CD4+ cells (from 0.68 x 10(9)/l to 0.23 x 10(9)/l), while CD8+, CD16+ and CD56+ cells were less affected. Despite the dramatic reduction of lymphocytes which lasted for more than 6 months, 7/10 patients with impaired NK function before starting 2-CdA therapy normalized the cytotoxic function within 2 months. In conclusion, 2-CdA produces a severe reduction of lymphocytes in general, and of CD4 lymphocytes in particular, whilst it may produce a significant increase in the proportion of NK cells leading, together with a normalization of the sIL-2R serum levels, to a rapid restoration of the NK cytotoxic function in the majority of patients.

High complete remission rate in hairy cell leukemia treated with 2-chlorodeoxyadenosine

2-Chlorodeoxyadenosine (2-CdA), a purine nucleoside, has been shown to be remarkably effective in the treatment of patients with hairy cell leukemia (HCL). We hereby report on the results achieved in 26 HCL patients treated with one single course of 2-CdA at a dose of 0.1 mg/kg daily for 7 days continuous infusion. Twenty-four were males and 2 females, with a median age of 56 years; all but 5 had been previously treated with Interferon-alpha (IFN-alpha). All cases are fully evaluable for their clinical and hematological response. Twenty of them (77%) achieved a complete remission and 6 a partial remission; two of the latter progressed after 6 and 12 months, respectively. The median duration of response was 13.8 months, ranging from 7 to 22 months from the end of therapy. Circulating hairy cells and spleen enlargement, when present, disappeared within 2 weeks after completing treatment; furthermore, a rapid normalization of soluble Interleukin-2 receptor serum levels was observed in all complete responders but one, and in 2 of the 6 partial responders. A significant lymphocytopenia was observed in almost all patients, whilst a severe neutropenia (< 500/microliters) was registered mainly in the 10 patients who had less than 1,000/microliters neutrophils when treatment was started; the hemoglobin and platelets were marginally affected in only a few cases. Eight of the 10 patients who developed severe neutropenia experienced fever; in 4 of them it was short-lived (24 hours) and apparently not infection-related, while the remaining 4 probably had an infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Massive abdominal lymphadenopathy in hairy cell leukaemia: a report of 12 cases

Lymphadenopathy is an uncommon finding in hairy cell leukaemia (HCL). We report 12 HCL patients in whom relapse was associated with massive abdominal lymphadenopathy. All but one had long-standing HCL (range 3-25 years; median 10 years); in one it was discovered at presentation. Nine patients had been splenectomized and seven had previously been treated with 2'deoxycoformycin (DCF) and/or alpha-interferon (alpha IFN): three had achieved complete remission and four a partial response. The computerized tomography (CT) scan appearances were similar in all cases with a primary lymph node mass centred around the coeliac axis and involving upper para-aortic and retropancreatic regions. Histology and/or cytology confirmed nodal involvement by HCL in six patients. Large immature hairy cells were seen in both lymph nodes and bone marrow, suggesting a degree of transformation. Nine patients were treated with DCF: one had complete resolution, six responded with 50-90% reduction of the lymphadenopathy, one did not respond and one is still on treatment; alpha-IFN was used concomitantly or sequentially in two of the responders. One responding patient died of sepsis after four injections of DCF. Three patients received either alpha- or beta-IFN alone with no response. One elderly patient was not treated. Abdominal lymphadenopathy could be part of the natural history of HCL and/or may represent a transformation analogous to that seen in other low-grade lymphoproliferative disorders. Routine abdominal CT scanning should be part of the work up of all patients with HCL.

Sequential administration of recombinant interferon alpha and deoxycoformycin in the treatment of hairy cell leukaemia

Both recombinant interferon alpha and deoxycoformycin (dCF) are effective in the treatment of hairy cell leukaemia. In an attempt to reduce the complications from dCF therapy, a pilot study of the Eastern Cooperative Oncology Group (ECOG) first treated patients with interferon to improve peripheral blood cell counts before dCF treatment began. Thirty-four patients were treated for 3 months with recombinant interferon alpha-2a (rIFN alpha-2a), 3 x 10(6) IU subcutaneously three times a week for 3 months, and then by dCF, 4 mg/m2 intravenously every 2 weeks for a maximum of 12 months. The overall response rate was 94% (32/34); 76% of patients (26/34) had complete response (CR) (90% confidence interval, 62-88%) and 18% (6/34) partial response. One patient was found to have a Mycobacterium avium infection while receiving rIFN alpha-2a. Without specific antimycobacterial therapy and with continued administration of rIFN alpha-2a and dCF, the infection resolved and he achieved CR. Three patients had culture-negative febrile episodes during the dCF phase of treatment. Non-disseminated herpes zoster developed in four patients, but three of the episodes occurred only after treatment was discontinued. Sequential administration of rIFN alpha-2a and dCF resulted in fewer infections (P = 0.027) than in ECOG's previous study of dCF used alone. Two patients died, one of combined hairy cell leukaemia and non-Hodgkin's lymphoma of intermediate histologic type 17 months after entry into the study and the other of cardiac arrest 20 months after entry. Thirty-two patients were alive with a median follow-up of 21 months (range 13-31 months). This combination produces durable CRs with a low incidence of infection.