Absence of prolonged benefit of initial leukapheresis therapy for hairy cell leukemia

Splenectomy, Interferon, and Treatments of Historical Interest in Hairy Cell Leukemia

The evolution and "lessons learned" for therapeutic options and approaches in HCL, which subsequently evolved into the adenosine deaminase inhibitors as the treatment of choice, has been intriguing. The contributions to patient care and individual patient lives have been remarkable. Observation, splenectomy, and recombinant interferon are potential therapeutic are alternatives in select patients as initial therapy, and as therapeutic alternatives in the 10% of patients who have progressive disease after the purine nucleoside analogs.

Splenectomy and treatments of historical interest

Hairy-cell leukaemia (HCL) was initially described as a distinct clinical entity in 1958. Various types of therapy have been evaluated since this initial description and several are currently important only for historical comparison. Hairy-cell leukaemia serves as an example of rapid progress in the development of effective therapeutic strategies. Splenectomy was the first effective treatment because it resulted in an improvement in cytopenias and relief from symptomatic splenomegaly. However, complete remission of the disease was observed only very rarely. Splenectomy was considered an appropriate initial therapy from the 1950s to the early 1980s, although no randomized controlled studies have ever shown improved survival with this approach. In the early 1980s, more effective treatments were identified, initially interferon-alpha, then the purine analogues 2-deoxycoformycin and 2-chlorodeoxyadenosine (2-CdA). These types of therapy have been so effective that most previous treatments are now obsolete. Although the purine analogues result in sustained remissions in the majority of patients, a relatively small percentage of patients relapse and require other types of therapy. Splenectomy may be necessary in some instances. In this chapter the role of splenectomy is reviewed and other types of therapy of historical interest are presented.

[Hairy cell leukemia: therapeutic approaches]

Hairy cell leukemia is a rare lymphoproliferative B disorder. It usually occurs in men older than 50 years. Until 1984, therapeutic approaches had been disappointing and most of the patients died from complications of cytopenia. The introduction of interferon and, more recently of purine analogues (pentostatine and 2-chlorodeoxyadenosine) improved outcome of this disease. Nevertheless, if complete remissions may be achieved sometimes with interferon and more frequently with purine analogues, none of these treatments seems able to remove hairy cells. So, therapeutic decision has to be made according to the efficacy and the potential adverse effects of these drugs.

Advances in therapy for hairy cell leukemia. A review

BACKGROUND

Hairy cell leukemia (HCL) is a chronic B-cell malignancy, typically seen in middle-aged men, characterized by pancytopenia, splenomegaly, immunologic abnormalities, and morphologically typical neoplastic mononuclear cells in the blood, bone marrow, liver, spleen, and other tissues. Diagnosis is confirmed by demonstration of hairy cells in biopsy specimens from the bone marrow or spleen or in peripheral blood. The natural history of this lymphoproliferative disorder varies. Patients may die early during the initial phase of therapy; others may require no therapy; and for some, splenectomy alone, without further treatment, may suffice for many years. Recently, the nucleosides pentostatin (2'-deoxycoformycin) (DCF) and 2'-chlorodeoxyadenosine (2-CdA) have been shown to produce greater numbers of durable complete remissions with curative potential in patients with HCL. The treatment options, with emphasis on major therapeutic advances with alpha-interferon, DCF, and 2-CdA, are reviewed in this article.

METHODS

Studies on HCL published from 1958 to 1992 were reviewed using the Cancerline and Medline retrieval systems and other bibliographies.

RESULTS

Management of HCL has changed in the last decade as a result of three new effective agents: alpha-interferon DCF, and 2-CdA. DCF has produced an overall response rate of 86% and a complete remission rate of 62%. 2-CdA has yielded an overall response rate of 95% and a complete remission rate of 82%. Alpha-interferon has given an overall response rate of 82% and a complete remission rate of 8%. Other agents with limited activities include chlorambucil, cyclophosphamide, cytarabine, vincristine, doxorubicin, and zorubicin hydrochloride. The effects of lithium carbonate, immunotherapy, splenic irradiation, androgens, and leukaphoresis are minimal and transient.

CONCLUSIONS

Modern management of HCL with 2-CdA and DCF is now potentially curative rather than palliative in some patients; however, the optimal therapeutic approach remains uncertain. Alpha-interferon has been approved by the Food and Drug Administration as the first-line drug therapy, followed by DCF in non-responding patients. 2-CdA remains an experimental therapy, but its higher response rate and ease of administration may make it the first-line treatment of choice. Additional research into the biology of HCL and further clinical trials are needed to determine the optimal treatment strategy for this disorder. Therefore, the best therapeutic approach at the current time is to include patients with HCL in ongoing clinical trials.

Peripheral blood and bone marrow changes following 2'-deoxycoformycin therapy in hairy cell leukemia. Results of 200 weeks' follow-up

Peripheral blood (PB) and bone marrow (BM) changes during 200 weeks' follow-up of 15 patients with hairy cell leukemia (HCL) undergoing low-dose 2'-deoxycoformycin (dCF) therapy are reported. Thirteen patients rapidly achieved complete remissions (CR) (median, 16 weeks). Previous splenectomy (two patients), or chemotherapy (two patients) had no effect on dCF response. Twelve patients have remained in CR. Patients with marked BM infiltration (hairy cell index [HCI] greater than 0.5; n = 5) had more pronounced pancytopenia and showed a slower hematologic recovery than those with a lesser degrees of infiltration. Additionally, patients with cytologic type II HCL (n = 5) had more pronounced pancytopenia with a greater tumor load in the BM, and exhibited slower hematologic recovery than those with type I (n = 5) HCL. There was a gradual decline in BM cellularity from 65% to 25% during year 1, a level which remained stable thereafter. Reticulin in the BM regressed in all nine patients in whom it was increased before dCF therapy. The authors have not seen any dysplastic changes in the hematopoietic cells during the period of follow-up.

Treatment of hairy cell leukemia with increasing doses of recombinant alpha A interferon

Since July 1984, eight patients with advanced hairy cell leukemia have received treatment with recombinant alpha A interferon. At commencement of interferon, seven patients had progressive cytopenia, and one was in leukemic phase (greater than 20 x 10(9)/L circulating hairy cells). All patients had had previous splenectomy. Interferon was administered subcutaneously. The initial dose was 3 x 10(6) U/day, continued until peripheral counts stabilised. Subsequently, patients received 6 x 10(6) U/day, 9 x 10(6) U/day, and finally 12 x 10(6) U/day. The dose increases proceeded every 8-12 weeks, as tolerated. Seven patients had an objective response. There were four complete remissions, two partial remissions, and one minor response. Complete remission was documented only in patients on at least 6 x 10(6) U/day for 12 weeks. The median time to complete remission was 40 weeks (range 35-53). Normalisation of peripheral blood counts preceded histologic marrow improvement. The median times for response (platelets greater than or equal to 100 x 10(9)/L, hemaglobin greater than or equal to 12 gm/dL, neutrophils greater than or equal to 1.5 x 10(9)/L), were six to eight and 17 weeks, respectively. Toxicity included myelosuppression during the first four weeks of therapy. With increasing doses of interferon, myelosuppression did not recur. A transient, mild, flu-like syndrome affected all patients. Two patients developed asymptomatic transaminitis at doses greater than 6 X 10(6) U/day. This resolved with dose reduction. In one case impotence was reported during the first four weeks of each interferon level.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical evaluation of bone marrow involvement in hairy cell leukemia during interferon therapy

Bone marrow biopsies from 7 patients afflicted with hairy cell leukemia were studied with a panel of monoclonal antibodies at different intervals during alpha recombinant interferon therapy. Monoclonal antibodies Dako-LC and F 8.11.13 were used because they are highly reactive with hairy cells, and 82H3 and LeuM 1 were also utilized to identify respectively the residual hemopoietic and myeloid tissue. All antibodies are reactive on sections of formalin-fixed, paraffin-embedded biopsy material. Before therapy a uniform hairy cell infiltrate was present and very little tissue was visible even after immunohistochemical staining. During therapy, identification of hairy cells in routine biopsies was difficult, since they were mixed with normal cells and the bone marrow was generally hypoplastic. Immunohistochemical stains seem to allow better identification of hairy cells and a more precise estimate of the degree of repopulation by normal bone marrow cells. It was evident, especially after immunocytochemical analysis, that interferon drastically reduced the extent of the infiltrate and allowed recovery of normal hemopoiesis, but did not produce complete remissions.

Remissions in hairy-cell leukemia with pentostatin (2'-deoxycoformycin)

The Eastern Cooperative Oncology Group conducted a study of pentostatin (2'-deoxycoformycin) in 37 patients with hairy-cell leukemia. Among the 27 patients who met all the study's entry criteria, the response rate was 96 percent, with 16 patients (59 percent) entering complete remission and 10 patients (37 percent) partial remission. In one patient no response was observed. These results were not significantly changed by the inclusion of nine additional patients who were found retrospectively not to have fulfilled the entry criteria. When complete remission was attained, maintenance therapy was not given. Despite this, no patient has had a relapse, and the duration of complete remission ranges from 1 to 375 days. Pentostatin appears to be equally effective in untreated patients and in those who have progressive disease after splenectomy or after both splenectomy and treatment with interferon. Whether pentostatin is superior to splenectomy or interferon as therapy for hairy-cell leukemia will have to be assessed by direct comparison in randomized studies. Lengthy follow-up will be required to determine a median duration for the responses of hairy-cell leukemia to pentostatin.

Hairy cell leukemia

Hairy cell leukemia is a chronic lymphoproliferative disorder that has been recognized as a separate clinical pathologic entity for the last 25 years. After a decade of discussions about the origin of the neoplastic cell, it has now been well established that hairy cells represent a certain, rather mature stage of B-cell differentiation. Evidence for this has been derived from studies using immunophenotyping with monoclonal and polyclonal antibodies, cytochemistry, and immunoglobulin gene rearrangement. For many years, splenectomy was the only therapy of proven value in hairy cell leukemia. For patients who showed insufficient response to the operation, chemotherapy with low-dose alkylating agents was moderately successful, whereas polychemotherapy often resulted in excessive toxicity. More recently, therapy with alpha-interferon has been shown to be very promising, whereas deoxycoformicin may be an attractive alternative. These new advances in immunology and therapy are reviewed.

Alpha interferon treatment of patients with hairy-cell leukaemia

We have treated 10 patients with hairy-cell, or hairy-cell-like leukaemia, for more than 6 months, with alpha interferon 3 X 10(6) IV/day I.M. or subcutaneously. All patients were severely pancytopenic before treatment. 7 patients had a typical hairy-cell leukaemia, whereas 3 lacked hairy cells but had the characteristic bone-marrow infiltration. The peripheral blood counts improved in all patients during treatment and the lymphoid infiltration of the bone-marrow was shown to decrease. 1 patient obtained complete remission, 6 partial remission and 3 had a minor response. It is concluded that alpha interferon is effective in the treatment of patients suffering from hairy-cell leukaemia.

Alpha interferon for induction of remission in hairy-cell leukemia

We treated seven patients who had progressive hairy-cell leukemia with daily doses of 3 million units of partially pure alpha (leukocyte) interferon by the intramuscular route. Three patients had a complete remission, and four had a partial remission, according to strict criteria for a response. After treatment, bone-marrow aspirates showed an absence of leukemia cells in three patients and 5 per cent or fewer in three others. Normalization of subnormal peripheral-blood values occurred in six of six patients with anemia, in seven of seven with granulocytopenia, and in four of four with thrombocytopenia. Remissions have been maintained for over 6 to over 10 months. Alpha interferon appears to be highly effective in patients with hairy-cell leukemia.

Hairy cell leukemia

Hairy cell leukemia is a malignancy with a variable course that can be relatively indolent or rapidly fatal. Alterations in the immune system are responsible for much of the morbidity and mortality from hairy cell leukemia. More than 60% of patients die from infection, and infections are both pyogenic and nonpyogenic. Many patients have transfusion requirements, and bleeding complications can also occur. Treatment strategies for hairy cell leukemia have evolved and are being modified as more is learned about the disease. Splenectomy is the initial treatment when patients become symptomatic, and if the disease progresses after splenectomy, chlorambucil offers good control in many patients. Radiation can be used for local palliation, as when complications such as bulky adenopathy or bone lesions occur. Initial studies using interferon in the treatment of hairy cell leukemia look encouraging, but more investigation is necessary before the role of interferon in treatment of hairy cell leukemia is determined.

Therapeutic cytapheresis in chronic lymphocytic leukemia

The role of therapeutic reductive lymphapheresis in 59 patients with chronic lymphocytic leukemia (CLL) was reviewed. Reduction in lymphocytosis, lymphadenopathy and hepatosplenomegaly was noted in 50%-60% of the patients studied. In addition to mobilization of the lymphoid tumor load, 40% of the patients showed an improvement in their hemogram. Although apheresis-induced anemia can occur, reported complications were minimal. These studies suggest that a majority of CLL patients might benefit from therapeutic lymphapheresis.