Should alpha interferon be used as primary treatment for hairy cell leukemia? Italian Cooperative Group for Hairy Cell Leukemia

Outcomes and second neoplasms in hairy cell leukemia: A retrospective cohort

Hairy cell leukemia (HCL) is a rare chronic B-cell lymphoproliferative disease which is treated on the basis of small studies, making the literature still scarce of reports, especially of those conducted in Latin America. Here we intend to describe clinical characteristics, rates of response, survival and second neoplasms in HCL patients treated in a reference center in Brazil. All patients diagnosed with HCL between July/1987 and Jun/2018 were included in this analysis. Fifty-four patients were included in this analysis. Median age at diagnosis was 55 years (range, 26-88), with 37% being above 60 years-old. Most patients were treated with cladribine in our cohort (n = 36; 68%), administered through intravenous continuous infusion. Remaining patients were firstly managed with splenectomy (n = 7; 13%), IFN (n = 6; 11%) and rituximab (n = 2; 4%). In a univariate analysis, platelet count and B2M level at diagnosis were statistically associated with CR achievement (p = 0.004 and p = 0.024, respectively). A median follow-up time of 9 years was calculated. Estimated 10-year overall survival was 91.1% (95% confidence interval, 77-97). In this cohort, 10 patients had any second neoplasm, diagnosed before or after HCL. Regarding the sites of cancer, 69% were of skin - 8/16 carcinoma-type and 3/16 melanoma-type. Our response and survival data are similar to those reported by literature, which reaffirms the role of purine analogs in current HCL management. With a very long follow-up we also have observed a high incidence of second neoplasm.

Long-term results of alpha interferon as initial therapy and splenectomy as consolidation therapy in patients with hairy cell leukemia. Final report from the Italian Cooperative Group for HCL

PURPOSE

In 1987 the Italian Cooperative Group for the Study of hairy cell leukemia (HCL) started a prospective trial with the following three major aims: 1) to confirm the effectiveness of alpha-IFN as first-line treatment; 2) to assess the usefulness of splenectomy as consolidation treatment in patients achieving a satisfactory partial remission (PR) with alpha-IFN, and 3) to explore whether splenectomy in patients achieving complete remission (CR) with alpha-IFN can reduce the risk of relapse after discontinuation of the drug.

PATIENTS AND METHODS

One-hundred seventy-seven patients with histologically-confirmed HCL were registered in the HCL88-A trial between December 1987 and January 1992. Inclusion criteria included no previous treatment and age less than 66 years. All patients received total doses of 3 MU of alpha-IFN daily for 12 months except for those who achieved early CR and would stop treatment after 6 or 9 months. Patients could be treated with different alpha-IFNs. At the time of the present analysis, 166 patients (93.8%) were fully evaluable.

RESULTS

Treatment of HCL patients with alpha-IFN at the onset of the disease resulted in 28 CR (16.9%), 103 PR (62.0%), and 27 Minor Remissions (MR) (16.3%). Patients treated with different alpha-IFNs achieved similar results: the overall response rate (CR + PR + MR) was 92.7%, 97.2%, and 95.3% for patients treated with r-alpha-2a, r-alpha 2b, and alpha-N1, respectively. The presence of a leukemic phase and a poor performance status were associated with a statistically significant lower response rate. Patients who were randomly assigned and underwent splenectomy after achieving a PR had a better but not significant 4-year progression-free survival than cases randomized for observation (53% vs. 22%, p = 0.116). Overall, 5 patients died after study entry, with an actuarial 5-year survival rate of 96% for the entire group of 166 patients. After a mean follow-up time of 38 months, only one second malignancy has been recorded.

CONCLUSIONS

Initial therapy with alpha-IFN, regardless of the type of alpha-IFN used, induces satisfactory responses in the majority of patients with HCL, but in most instances discontinuation of treatment results in recurrence of disease. In most cases alpha-IFN improves the performance status of patients and favors a satisfactory bone marrow recovery and thus could still play a role in the initial management of the disease. Although splenectomy following alpha-IFN could prolong the progression free survival, its use should be restricted to selected cases.

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.

Hairy cell leukemia: a clinical review based on 725 cases of the Italian Cooperative Group (ICGHCL). Italian Cooperative Group for Hairy Cell Leukemia

The Italian Registry for hairy cell leukemia (HCL) has recorded 725 patients with HCL diagnosed over 25 years. We analysed this large series of patients with the aim of providing an evaluation of changes in clinical presentation, impact of initial therapy and modifications in prognostic factors over the period of two decades. Over time, a progressive down-staging of the disease at the onset, along with a reduction of patients with severe anemia and marked splenomegaly, has been observed. A second malignancy was found in 3.7% of patients, mostly detected several years after the onset of HCL. A striking improvement of survival rates has been observed, from 58.9% survival at five years for patients diagnosed before 1985 to 87.5% at five years for patients diagnosed after 1985 (p < 0.0001). Before 1985 hemoglobin alone provided prognostic information, whereas after 1985, clinical stage and the number of leukocytes correlated better with patient outcome. Survivals at 5 and 10 years were 34.4% and 29.6% respectively for untreated patients, 58.8% and 44.1% for patients receiving chemotherapy, steroids or other drugs, 64.1% and 56.1% for splenectomized patients and 88.9% (at 5 years) for alpha interferon (IFN)-treated patients (p < 0.0001). Our findings suggest that IFN has improved the prognosis of HCL, and that it must be considered a good initial treatment for patients with HCL.

An interferon resistant variant of the hairy-cell leukemic cell line, Eskol: biochemical and immunological characterization

The B-lymphoblastoid cell line Eskol, which is composed of differentiated cells resembling hairy-cell leukemia, has been used to study the effects of type I interferon in vitro. In order to study the mechanism of delayed interferon therapy resistance, a hairy-cell leukemia-like clonal cell line (IREs-4) was isolated from Eskol after 4 months of exposure to r-metIFN-con1. When compared to Eskol cells, the IREs-4 cells were resistant to the antiproliferative effect of type I interferons as well as interferon induced protection against LAK cells. Treatment of IREs-4 with type I interferon did not induce MHC antigens, although both MHC class I and II antigens were induced in Eskol. Binding studies indicated the presence of equal numbers of high affinity binding sites with similar affinities on both cell lines. The resistant phenotype appears to result from an intracellular event which is essential to interferon signal transduction. It is hypothesized that this variant may reflect heterogeneity in the normal population of hairy-cell leukemia cells, and may explain the partial resistance of HCL patients to IFN therapy.

Three years' continuous low-dose interferon-alpha treatment of hairy-cell leukaemia: evaluation of response and maintenance dose

Thirty-six HCL patients were treated with 2 x 10(6) U/m2 IFN-alpha-2b three times weekly for 24 months, followed by 12 months of treatment with one of three doses ranging from 0.5 x 10(6) U to 2 x 10(6) U/m2. For most patients the response continued to improve during the whole treatment period, and there were no cases of disease progression during treatment. Patients with disease of short duration before IFN treatment and/or non-splenectomized patients seemed to respond more slowly than others, but there were no differences between patients treated with the different IFN doses. Toxicity was usually WHO grade 1 or 2. The continued improvement in a large number of patients even with very small IFN doses might indicate that only a small number of true complete responses are reached after 24 months of treatment, thus explaining the reported high relapse rate after early discontinuation of treatment. It therefore seems worthwhile--also from a cost/benefit point of view--to test long-term or continuous IFN-alpha treatment at other centres.