Survival Experience of 195 Patients with Hairy Cell Leukemia Treated in a Multi-Institutional Study with Interferon-Alfa 2B

Panuveitis responsive to 2-CdA: an unusual ocular presentation of hairy cell leukemia

Systemic involvement in hairy cell leukemia (HCL), has rarely been reported but ocular involvement is extremely uncommon. We report an unusual ocular presentation of HCL due to panuveitis with dramatic improvement following treatment with 2-chlorodeoxyadenosine (2-CdA).

The interferons in haematological malignancies

Interferons (IFNs) are a family of biological response modifiers with a broad spectrum of action on cellular proliferation as well as immunoregulation. In the last decade, these properties have prompted several investigations of the effect of IFNs on various haematological malignancies. IFNs-alpha have been used most extensively. The response rate is dependent on the type of the disease. The most striking effects have been observed in hairy cell leukaemia and chronic myeloid leukaemia. In both these malignancies the results are well consolidated and indicate that IFNs-alpha have modified the natural history of the disease. Results of IFN therapy in low grade lymphoma, cutaneous T-cell lymphoma and multiple myeloma suggest a beneficial role of IFNs-alpha in the induction, as well as the maintenance, phase. The efficacy of IFNs is now widely confirmed in treating patients with essential thrombocythaemia or polycythaemia vera. However, the role of IFNs in the management of chronic lymphocytic leukaemia and myelofibrosis with myeloid metaplasia is still controversial.

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.

Agar capillary clonogenic microassays for cellular immunocytotoxic activities in human leukaemia and lymphoma

Current concepts of immunotherapeutic approaches in leukemias and lymphomas using activated cytotoxic lymphocytes and macrophages are briefly reviewed. Defective cellular immunocytotoxic activities and effects of interleukins and chemotherapeutic drugs thereupon are discussed. In vitro assays to measure lymphokine-activated killer (LAK) and natural killer (NK) cell activities suffer from various problems, depending on the quality of the endpoints. Our clonogenic microassay for LAK cell activity, using agar-containing glass capillaries, avoids some of the potential artifacts and offers several advantages that are discussed. As an example the stimulatory effect of low mafosfamide concentrations on the LAK cell activity versus K562 human myeloid leukemia cells is demonstrated. Thus, our clonogenic LAK microassay provides a valid tool for preclinical screening of immunomodulatory agents.

Low Dose Interferon Alfa-2B for the Induction of Remission of Hairy Cell Leukemia: A Multi-institutional Study of 49 Patients

This multicenter study reports on 49 patients with hairy cell leukemia (HCL) who were treated subcutaneously with alfa-2b interferon (Intron A, Schering Corporation, Kenilworth, N.J.), three times a week at a reduced dosage of 200,000 units/m(2), one-tenth the dose of the standard 2 million units/m(2). The response rate (normalized blood counts) was 22% (11 of 49); an additional 12 patients had a minor response for an overall response rate of 47% (23 of 49). When response was assessed by prior IFN therapy, no significant difference was noted. Five of 21 (24%) with no prior IFN and 6 of 28 (21%) with prior IFN therapy achieved at least a normalization of blood counts (p = 0.07). The response rate with low-dose interferon is inferior to that with standard dose interferon and should not be used for remission induction, but should be evaluated for its role in long-term maintenance of response.