Recombinant human interferon (IFN) alpha-2b in chronic myelogenous leukaemia: dose dependency of response and frequency of neutralizing anti-interferon antibodies

Development of neutralizing antibodies to intramuscular interferon beta-1a (Avonex ®)

The most frequent treatment for relapsing-remitting multiple sclerosis (RRMS) is interferon beta (IFNβ). Development of neutralizing antibodies (NAbs) to IFN therapy is a well-documented phenomenon. Patients who have persistent NAbs of sufficient titer no longer receive clinical benefit from these therapies. In the case of intramuscular (IM) IFNβ-1a (Avonex®), approximately 22% of patients in the pivotal trial (conducted from 1990 to 1994) developed NAbs. However, improvements in the processes for the production of IFNβ-1a-Avonex resulted in a commercial product (first released in 1996) that was significantly less immunogenic; approximately 2% of patients developed NAbs with titers ≥20 neutralizing units (NU)/mL. In a large three-year Phase IV clinical trial using IFNβ-1a-Avonex, it was shown that NAb-positive patients had significantly greater annual relapse rates, greater increases in disability (compared with baseline), and more lesions detected by MRI compared with NAb-negative patients, indicating that the development of NAbs has serious consequences for patients with MS treated with IFNβ. Therefore, maintaining the low immunogenicity of IFNβ-1a-Avonex in the context of improving formulations and delivery options, has been a critical objective for Biogen Idec in the development of this important therapy for patients with MS. Multiple Sclerosis 2007; 13: S14—S20 http://msj.sagepub.com

Significance of neutralizing antibodies to interferon beta during treatment of multiple sclerosis: expert opinions based on the Proceedings of an International Consensus Conference

On August 30, 2002, an international panel of neurologists who specialize in the treatment of multiple sclerosis (MS) was convened in Paris (France) to discuss the issue of neutralizing antibodies (NAb) to interferon beta (IFN-beta) therapy in patients with MS. The goals of this meeting were to: (i) review the most recent clinical information on NAb, (ii) come to a consensus on the clinical relevance of NAb in the management of patients with MS receiving IFN-beta therapy, and (iii) establish a framework for the development of patient management guidelines based on scientific consensus. The meeting was chaired by Hans-Peter Hartung (Heinrich-Heine University, Düsseldorf, Germany) and Huub Schellekens (Utrecht University, Utrecht, the Netherlands). This article summarizes the opinions of the expert panel on a number of key issues raised at the meeting.

Interferon therapy in chronic myelogenous leukemia

Interferon (IFN)-alpha, the molecule used in the treatment of chronic myelogenous leukemia and initially prepared from human leucocytes,is now produced essentially by recombinant techniques. Polyethylene glycol (PEG) modifications of proteins could be more effective than the regular molecules; thus, pegylated IFNs more recently have been tested in chronic myelogenous leukemia. PEG modification of proteins reduces sensitivity to proteolysis. Moreover,administration of pegylated IFNs results in less antigenicity and immunogenicity, and prolongation of their plasma half-life has been assessed by pharmacokinetic studies. It is assumed, therefore, that this compound could be more effective and better tolerated. Given the results recently obtained with imatinib, however, whether IFN-alpha will still have a therapeutic role is questionable.

Treatment intensity significantly influencing fibrosis in bone marrow independently of the cytogenetic response: meta-analysis of the long-term results from two prospective controlled trials on chronic myeloid leukemia

Bone marrow fibrosis (MF) has been shown to indicate therapy failure in Ph(+) chronic myeloid leukemia (CML). However, the results on the development of MF during interferon-alpha therapy of CML are controversial. The significance of the interferon dose has not been considered as yet. In total, 627 bone marrow biopsies taken prospectively from 200 patients with CML recruited in two studies using different doses of interferon-alpha +/- low-dose cytosine arabinoside were examined for MF before and during therapy. The results showed that the risk of MF depended significantly on the interferon-alpha dose applied (P<0.000005). MF progressed during low-dose therapy (3 x 5 x 10(6) IU/week), but was prevented from progression when applying high dose (5 x 10(6) IU/m(2)/per day). MF disappeared when high-dose interferon-alpha was combined with low-dose cytosine arabinoside (P<0.000005). The risk of death markedly increased when MF occurred or progressed (P<0.0009), independent of all other prognostic factors evaluated including the cytogenetic response. In conclusion, the effectiveness of interferon-alpha on MF depends on the treatment intensity. MF reverses when combining high-dose interferon-alpha with low-dose cytosine arabinoside, but progresses when applying low-dose interferon-alpha. MF appears to be a significant early indicator of ineffective therapy in CML.

Biochip as a potential platform of serological interferon α2b antibody assay

The formation of antibodies against cytokines may play a major role in the generation of the immune response and may affect treatment protocols with recombinant cytokines. Interferon (IFN) is one of the effective therapeutic agents with anti-viral and anti-tumor specific effects. The appearance of IFN antibodies in patients may limit the natural and the therapeutic effect by IFNs. In contrast to conventional ELISA techniques, we here report a simple biochip methodology that enables identification of antibodies against cytokines and peptides. The method takes advantage of a functionalized self-assembled monolayer modified by N-hydroxysuccinimide (NHS). To validate this surface, four human proteins: IFNalpha2b, leptin, growth hormone and human IgG, with molecular sizes ranging between 14 and 150 kDa, were used. A number of other parameters for protein assay conditions by array technology were evaluated concomitantly. Finally, 56 serum samples from patients treated with recombinant human IFNalpha2b were simultaneously tested on single chip. In these patients, 16.1% (9 of 56 cases) were positive for IFNalpha2b antibodies. All results were confirmed in an ELISA, specific for the identification of IFNalpha specific antibodies in human samples. The potential application of this protein biochip can be amplified rapidly and reliably to test not only IFNalpha2b, but also other cytokine specific antibodies. The clinical relevance of such assays for investigations in autoimmune disorders is expected.

Human immune response to recombinant human proteins

Delivery of pharmacological doses of proteins to people has raised concerns of inducing immune responses, especially when the protein is provided in multiple doses over an extended period of time. Immune responses could impact the therapeutic exposure and efficacy of the protein itself. In addition, there have been fears of anaphylaxis or autoimmunity. This review summarizes the available literature regarding the measurement and evaluation of immune responses observed during clinical assessment of recombinant human proteins. Immune responses have ranged from none at all to inactivation and/or accelerated clearance. Presence of antibodies does not necessarily impact therapeutic viability. While responses are related to frequency and route of delivery, there is no clear relationship that enables one to predict the clinical experience.

Extramedullary blast crisis in a patient with chronic myelogenous leukemia in complete cytogenetic and molecular remission on interferon-alpha therapy

We report the previously undescribed occurrence of extramedullary blast crisis in a patient with chronic myelogenous leukemia in complete cytogenetic and molecular remission on interferon-alpha. Development of bilateral testicular swelling prompted a biopsy showing stromal infiltration with CD20 and TdT positive immature cells. On repeated examinations, the bone marrow remained BCR/ABL negative by RT-PCR analysis. However, the cerebrospinal fluid (CSF) contained atypical lymphocytes positive for the P210 BCR-ABL product. Following treatment with testicular irradiation, intrathecal methotrexate, systemic chemotherapy and an unrelated donor transplant, the patient showed no evidence of disease until 9 months post-transplant, when he relapsed in lymphoid blast crisis in both bone marrow and CSF.

Neutralizing and binding anti-interferon-beta (IFN-beta) antibodies. A comparison between IFN-beta-1a and IFN-beta-1b treatment in multiple sclerosis

Interferon-beta (IFN-beta) is currently the most commonly used treatment of relapsing-remitting multiple sclerosis (MS). At the time of this study, two preparations of IFN-beta were available, IFN-beta-1a (Avonextrade mark) and IFN-beta-1b (Betaferon(R)), which both can elicit an immune response with the development of anti-IFN-beta antibodies. Direct comparisons between these two preparations regarding antibody frequencies have, however, been difficult to perform, because two different analysis methods measuring partly different biological effects of IFN-beta have been employed. In the present study, binding and neutralizing anti-IFN-beta-1a and -1b antibodies were detected in parallel by an independent, well-acknowledged, interferon research laboratory using an immunoassay and a cytopathic virus inhibition assay. Five per cent of patients treated with IFN-beta-1a intramuscularly (n = 20) had neutralizing antibodies (NABs) compared with 44% of patients treated with IFN-beta-1b subcutaneously (n = 48). A high degree of cross-reactivity between neutralizing anti-IFN-beta-1a and -1b antibodies was observed. No effect of NABs on clinical outcome could be detected in this limited material. Binding anti-IFN-beta antibodies were observed in 20% of IFN-beta-1a treated patients compared with 81% of patients treated with IFN-beta-1b. Only one of 17 patients examined (6%) had detectable titres of binding anti-IFN-beta-1b antibodies in the cerebrospinal fluid (CSF). These data are the first using identical methodology to show that IFN-beta-1a gives rise to fewer NABs than IFN-beta-1b at recommended treatment schedules.

Treatment of Philadelphia chromosome-positive early chronic phase chronic myelogenous leukemia with daily doses of interferon alpha and low-dose cytarabine

PURPOSE

To evaluate the efficacy of the combination of interferon alpha (IFN-alpha) and daily low-dose cytarabine (ara-C) in the treatment of patients with early chronic-phase chronic myelogenous leukemia (CML) (within 1 year of diagnosis). Improving the degree of hematologic and cytogenetic response in patients with Philadelphia chromosome (Ph)-positive CML may improve prognosis. Both IFN-alpha and ara-C induce cytogenetic responses as single-agent therapy in CML.

PATIENTS AND METHODS

One hundred forty patients with Ph-positive early chronic-phase CML received subcutaneous injections of IFN-alpha 5 megaunits/m2 daily and ara-C 10 mg daily. Their median age was 46 years; 53% had good-risk disease, 33% had intermediate-risk disease, and 14% had poor-risk disease. Their results were compared with those of patients receiving IFN-alpha with or without intermittent ara-C (7 days/mo).

RESULTS

A complete hematologic response (CHR) was achieved in 92% of patients. A cytogenetic response was seen in 74%: it was major in 50% (Ph-positive < 35%) and complete in 31% (Ph-positive 0%). With a median follow-up of 42 months, the 4-year estimated survival rote was 70% (95% confidence interval, 61% to 79%). Significant side effects included fatigue (43%; grade 3/4, 11%), weight loss (19%; grade 3/4, 11%), muscle and bone aches (20%; grade 3/4, 7%), oral ulcers (4%), diarrhea (6%), and neurologic changes (27%, grade 3/4, 6%). The median dose of IFN-alpha was 3.7 megaunits/m2 daily, mainly because of reductions for myelosuppression (70% of cases); the median ara-C dose was 7.5 mg daily. Prognostic risk groups were predictive for response to the IFN-alpha plus ara-C combination. The incidence of CHR was higher with IFN-alpha plus daily ara-C compared with IFN-alpha plus intermittent ara-C and IFN-alpha alone (no ara-C) (92% v 84% v 80%, P = .01), as were the incidences of cytogenetic response (74% v 73% v 58%; P = .003) and major cytogenetic response (50% v 38% v 38%; P = .06). The median time to achievement of major cytogenetic response was significantly shorter than that for previous IFN-alpha regimens (7 v 10 v 12 months; P < .01). However, with the present follow-up, the survival and time to blastic transformation were similar.

CONCLUSION

The combination of IFN-alpha plus daily low-dose ara-C seems to be promising for the treatment of CML. High rates of CHR and cytogenetic response were observed with acceptable toxicity and a lower daily dose of IFN-alpha compared with our previous studies.

Clinical course and therapy of chronic myelogenous leukemia with interferon-alpha and chemotherapy

This article begins with a review of the natural history of chronic myelogenous leukemia (CML), with an emphasis on prognostic features. Current standard therapy of CML with interferon-alpha based regimens, and interferon-alpha, in the context of allogenic stem cell transplantation is then discussed. Finally, some potentially effective novel agents including homoharringtonine, decitabine, ATRA, and topotecan are described.

Interferons Alpha, Beta, and Omega

Interferon alpha (IFN-α) is a mixture of closely related proteins, termed “subtypes,” expressed from distinct chromosomal genes. Interferon β (IFN-β) is a single protein species and is molecularly related to IFN-α subtypes, although it is antigenically distinct from them. IFN omega (IFN-ω) is antigenically distinct from IFN-α and IFN-β but is molecularly related to both. The genes of three IFN subtypes are tandemly arranged on the short arm of chromosome 9. They are transiently expressed following induction by various exogenous stimuli, including viruses. They are synthesized from their respective mRNAs for relatively short periods following gene activation and are secreted to act, via specific cell surface receptors, on other cells. IFN-α subtypes are secreted proteins and as such are transcribed from mRNAs as precursor proteins, pre-IFN-α, containing N-terminal signal polypeptides of 23 hydrophobic amino acids (aa) mainly. Pre-IFN-β contains 187 aa, of which 21 comprise the N-terminal signal polypeptide and 166 comprise the mature IFN-β protein. IFN-ω contains 195 aa—the N-terminal 23 comprising the signal sequence and the remaining 172, the mature IFN-ω protein. At the C-terminus, the aa sequence of IFN-ω is six residues longer than that of IFN-α or IFN-β proteins. IFN-α, as a mixture of subtypes, and IFN-ω may be produced together following viral infection of null lymphocytes or monocytes/macrophages. The biological activities of IFNs are mostly dependent upon protein synthesis with selective subsets of proteins mediating individual activities. IFNs can also stimulate indirect antiviral and antitumor mechanisms, depending upon cellular differentiation and the induction of cytotoxic activity.

Antibodies to interferon-alpha in treated cancer patients: incidence and significance

Antibodies to interferon-alpha (IFN-alpha) are found in some patients being treated with this cytokine. In studies in which two recombinant IFN-alpha preparations were directly compared in cancer patients, those given IFN-alpha2a were found to have neutralizing antibodies in their serum significantly more often than those given IFN-alpha2b (p <0.001). Patients who develop neutralizing antibodies are more likely to have a clinical relapse and to become resistant to further treatment with at least the IFN preparation initially used for their treatment. In 10 studies in cancer patients, such an outcome was found in 63% of those who developed antibodies but in only 13% of those who did not. These data are tabulated.

Practical guidelines for the management of chronic myelogenous leukemia with interferon alpha

Interferon-A (IFN-A) is an effective agent in the treatment of chronic myelogenous leukemia (CML). Hematologic remissions occur in the majority of patients with newly diagnosed disease, and cytogenetic remissions may occur in up to 50% of patients. Several studies have shown a correlation between the dose of IFN-A and achievement of a major cytogenetic response; this response has also been correlated with prolonged survival. However, IFN-A may be associated with significant side effects that reduce enthusiasm for the use of this drug, produce difficulties in patient compliance, and limit the dose delivered to the patient, thus resulting in ineffective use of IFN-A. Experience with this drug has led to a refinement in techniques for initiation of therapy as well as interventions to deal with side effects. These strategies are often not discussed in publications dealing with response rates and survival. In this review we discuss strategies to minimize toxicity and improve the effectiveness of IFN-A in the treatment of CML.

Natural leukocyte interferon-alpha therapy in patients with chronic granulocytic leukemia who have antibody-mediated resistance to treatment with recombinant interferon-alpha

Two patients with chronic-phase chronic granulocytic leukemia initially responded to recombinant interferon alpha-2a (rIFN-alpha-2a) but relapsed as a result of development of hightiter neutralizing antibodies to rIFN-alpha-2a. Both patients were subsequently treated with natural leukocyte IFN-alpha (IFN-alpha-n3), and one of the two patients achieved a durable second hematologic and cytogenetic remission. IFN-alpha-n3 may be considered for patients in whom antibody-mediated resistance to rIFN-alpha-2a develops.

Chronic myelogenous leukemia: a review

Chronic myelogenous leukemia (CML) is a chronic myeloproliferative disorder with an initially chronic course lasting for 3-5 years. It eventually transforms into accelerated and blastic phases, which are generally fatal. CML was one of the first diseases in which a specific chromosomal abnormality was identified, a t(9;22)(q34;q11) or Philadelphia chromosome. CML had been traditionally treated with conventional chemotherapy with hydroxyurea or busulfan. Although these agents can achieve hematologic remissions in most patients, no evidence of sustained disappearance of the chromosomal abnormality was evident. Interferon alpha (IFN-alpha) has been able to achieve hematologic and cytogenic remissions in a significant number of patients, and recent studies show a survival advantage for patients treated with IFN-alpha compared with those treated with conventional chemotherapy. The results of these studies are discussed, and the reasons for discordance among different investigators analyzed in this review. Allogeneic bone marrow transplantation (BMT) may be curative in some patients with CML. The benefits and limitations of this approach in the treatment of CML are also discussed and the results of different alternatives compared. Other alternatives of therapy, including newer chemotherapeutic agents, combinations of IFN-alpha with other agents, and autologous BMT, are presented. The availability of very sensitive techniques for detection of the Philadelphia chromosome at the molecular level has allowed the detection of minimal residual disease. The information available on these measurements is also analyzed. Finally, we discuss the alternatives for patients with accelerated and blastic phase CML, as well as the clinical characteristics and prognosis for patients with Philadelphia-chromosome-negative CML.

Natural killer cells and cancer

BACKGROUND

Natural cytotoxicity, mediated by natural killer (NK) cells and cell with lymphokine-activated killer (LAK) activity, is believed to play an important role in host anti-cancer mechanisms.

METHODS

The authors critically review recent publications on the role of natural cytotoxicity in patients with cancer.

RESULTS

In patients with cancer, several studies have noted variations in the numbers and activity of NK and cells with LAK activity in different body compartments. NK cell activity in the peripheral blood lymphocytes (PBLs) is higher than that found in lymph nodes and within tumors, and this appears to be due to the presence of suppressor factors. The natural cytotoxicity of PBLs in patients with different types of cancers varies. However, there appears to be a trend for natural cytotoxicity to be reduced in certain cancer patients, possibly related to tumor volume or dissemination. Anti-cancer treatments (e.g., surgery, hormonal modulation, radiotherapy and chemotherapy) can also result in suppression of natural cytotoxicity, although the long-term effect on response to treatment and development of metastases is at present unknown.

CONCLUSIONS

NK and LAK cells, through the use of immune biologic modifiers, have been demonstrated to have a therapeutic role in the treatment of human cancers. Further studies are required to determine the optimal dosages and combinations of chemotherapeutic agents, the timing of surgery, and the adjuvant use of immune biologic response modifiers. An increasing awareness and understanding of this field, may allow for the future development of anti-cancer therapies.

Interferon-alpha therapy for chronic myelogenous leukemia

PURPOSE

To provide a status report on the use of interferon (IFN)-alpha in patients with chronic myelogenous leukemia (CML).

DATA SOURCES

Data on IFN-alpha therapy for CML collected from published articles identified in a MEDLINE computer search.

RESULTS

Previously untreated patients with low-risk factors and early-stage disease consistently had the best results in clinical trials. A dose response was seen, with patients treated with dosages of 5 million units (MU)/m2 per day showing the greatest incidence of cytogenetic remissions. In addition, randomized trials showed a survival advantage for IFN-alpha-treated patients. In studies comparing IFN-alpha therapy to chemotherapy, IFN-alpha produced significantly more major and durable cytogenetic responses than chemotherapy did. In studies combining IFN-alpha and chemotherapy, patients had significantly more cytogenetic responses, although more patient accrual and follow-up data are needed to offer conclusive statements concerning durability of response. IFN-alpha also showed activity in maintaining remissions after both chemotherapy and bone marrow transplantation.

CONCLUSIONS

IFN-alpha has significant activity in patients with CML, with best results at dosages of 5 MU/m2 per day. At these dosages, in patients with early-stage, Philadelphia+ CML, hematologic response rates of 70% to 80% and cytogenetic response rates of 50% (approximately 20% of which were complete) are seen. One randomized trial shows a survival advantage with cytogenetic response in IFN-alpha-treated patients, and this advantage appears to be unrelated to the degree of that response. These questions remain under study.

Biotherapy of chronic myelogenous leukemia

The aim of this review is to summarize the current knowledge on the clinical results of biotherapy of chronic myelogenous leukemia (CML) and potential mechanisms of the antitumor action of interferon alpha. IFN alpha treatment induces hematologic and cytogenetic remissions in patients with chronic phase CML. In addition, the duration of the chronic phase is prolonged by IFN alpha resulting in a significant survival benefit. In two randomized clinical trials this survival benefit was demonstrated in all chronic phase CML patients independent of their risk scores. Moreover, IFN treatment also delays the onset of clinical relapse after allogeneic bone marrow transplantation. The critical mechanisms of IFN action have not yet been identified. Both direct and indirect antiproliferative mechanisms have been described. In particular, differential regulation of growth promoting and growth inhibiting cytokines represents an attractive hypothetical mechanism of IFN action. Nevertheless, no leukemia specific IFN activities explaining cytogenetic remissions and/or delay of disease progression have been identified. Further research on that field are required to further improve biological CML therapies.

Neutralising antibodies in patients with multiple myeloma receiving maintenance therapy with interferon alpha 2b

In a study of 29 patients who were receiving or had received interferon alpha 2b (IFN-alpha 2b) as maintenance therapy for multiple myeloma, antibodies were detected in 58% (17/29) of patients measured by a solid-phase enzyme-linked immunosorbent assay (ELISA). Only 7/17 patients who were positive for antibody in the ELISA had neutralising antibody to IFN-alpha 2b, measured by virus growth inhibition. These patients comprised six who were receiving IFN-alpha 2b at the time of assessment and one who had finished treatment. Among patients who were receiving the cytokine, four had progressive disease, one was in complete remission and one in partial remission. Neutralising activity was also detected to natural human leucocyte IFN-alpha in the same patients. Two patients who were positive for neutralising antibody remain in remission and are continuing to receive IFN-alpha 2b. These two patients have since lost their neutralising titre. No neutralising antibody to IFN-alpha 2b or natural human leucocyte IFN-alpha was detected in serum from six normal donors. The data suggest that neutralising antibody formation in patients with multiple myeloma is not responsible for relapse in patients receiving IFN-alpha 2b. The transient nature of neutralising antibody production in patients who remain in remission suggests that this response to IFN-alpha 2b is not associated with memory B cells.

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.

Divergent in vivo and in vitro antileukemic activity of recombinant interferon beta in patients with chronic-phase chronic myelogenous leukemia

It was the aim of this study to investigate the antileukemic activities of recombinant interferon beta (rIFN beta) in chronic-phase CML in vitro and in vivo. Nine patients in the early chronic-phase of CML were treated in a phase-II trial with escalating doses of rIFN beta. In parallel, antiproliferative and immunomodulatory activities of rIFN beta and rIFN alpha 2b were studied in vitro. rIFN beta exhibited a significantly higher antiproliferative activity on hematopoietic progenitor cells of CML patients in vitro than rIFN alpha 2b. In contrast, only very limited clinical antileukemic efficacy of rIFN beta was observed. None of the patients achieved a complete or partial hematologic response (0% response rate, 0-36% 95 C.I.). Primary resistance of CML patients to rIFN beta treatment was caused neither by antibody formation against the recombinant material nor by deficient IFN receptor targeting and/or signaling; Induction of serum levels of beta-2-microglobulin (beta-2-m) and neopterin after administration of rIFN beta was comparable to that seen after administration of rIFN alpha. However, rIFN beta treatment less effectively induced biosynthesis of interleukin-1 receptor antagonist protein (IL-1-Ra) than rIFN alpha 2b. Thus, we conclude that rIFN beta at doses up to 12 MU/day s.c. is ineffective for treatment of chronic-phase CML. Further investigations into divergent biologic responses to various type-I interferons might help to elucidate mechanisms crucial for IFN action in patients with CML.

Treatment of chronic hepatitis C with high-dose interferon alpha-2b. A multicenter study

A comparative study of three different high-dose regimens of interferon-alpha-2b (IFN) was conducted in patients with chronic hepatitis C to determine which was better at obtaining a sustained remission. A total of 126 patients were assigned randomly to one of three groups: group A was given 10 million international units (MIU) of IFN six times a week for eight weeks; group B was given 10 MIU IFN six times a week for four weeks followed by three times a week for an additional eight weeks; group C was given 10 MIU IFN six times a week for two weeks followed by three times a week for 12 weeks. The total dose administered to each group was 480 MIU/patient. Only the dosing schedule varied among the three groups. Among 98 efficacy-evaluable patients, a sustained alanine aminotransferase (ALT) response, defined as persistent normalization of the ALT for greater than six months after the termination of treatment, was achieved in 21.2% (7/33) of group A, 42.3% (11/26) of group B, and 54.5% (18/33) of group C patients. Similarly, a sustained loss of measurable serum hepatitis C virus RNA was observed in 28.6% (8/28) of group A, 40.9% (9/22) of group B, and 48.3% (14/29) of group C patients. Based upon these data, it can be concluded that 10 MIU of IFN administered six days a week for two weeks followed by three times a week for an additional 12 weeks produces the highest rate of both biochemical and virological responses to IFN therapy in patients with chronic HCV.

Interferon-alpha antibodies in patients with renal cell carcinoma treated with recombinant interferon-alpha-2A in an adjuvant multicenter trial. The Delta-P Study Group

BACKGROUND

Prolonged therapy with interferon (IFN) may lead to the formation of IFN antibodies.

METHODS

Patients with renal cell carcinoma (n = 270) with advanced localized disease were randomized after complete tumor resection to receive treatment with adjuvant recombinant IFN-alpha-2a (rIFN-alpha 2a) (9 x 10(6) IU subcutaneously, three times per week for a maximum of 12 months) versus no treatment. Patients (IFN-treated group, 106 patients; control group, 97 patients) were monitored for the presence of rIFN-alpha 2a antibodies.

RESULTS

Of 86 IFN-treated patients observed for more than 2 months, 40 (47%) had IFN-alpha 2a-binding and 25 (29%) had IFN-alpha 2a-neutralizing antibodies developed within a median of 3 and 6 months, respectively. A distinct peak in binding antibody titers occurred at 6-9 months. Therapy-induced neutralizing antibodies were equally reactive with two other recombinant IFN-alpha-2 subtypes but poorly recognized natural IFN-alpha (IFN-alpha), recombinant IFN-alpha-1/alpha-8, and recombinant IFN-omega-1. The duration of remission and rate of relapse were independent of the antibody status, although neutralizing and most non-neutralizing antibodies correlated with a reduction in the IFN-induced increase in beta-2-microglobulin levels.

CONCLUSIONS

Patients treated with IFN-alpha 2a should be monitored for the presence and clinical relevance of IFN-alpha antibodies to determine those who could respond to alternative treatment.

Treatment of chronic myeloid leukemia with interferon alpha (Roferon): results of the Israeli Study Group on CML

Thirty patients with chronic myeloid leukemia from 11 Israeli medical centers entered this study. Their ages ranged from 16-65 (median 41) and time from diagnosis to treatment was 1-16 months (median 4 months). After cytoreductive therapy with hydroxyurea (22 patients) or busulphan (8 patients), patients received 9 million units/day of recombinant interferon alpha-2 alpha (Roferon A) subcutaneously. Side effects included arthralgia or low back pain in 7 patients, thrombocytopenia in 9, weight loss in four, neurologic disturbances in 4 and leukopenia in 3 cases. Seventeen patients achieved complete hematologic remission (CHR) and 6 partial hematologic remission (PHR). Six patients achieved major cytogenetic response, 4 of them lost all Ph1 chromosome positive cells and 4 had minimal cytogenetic response. Frequency of relapse was high: 8 patients with CHR and 6 with PHR relapsed, but patients with major cytogenetic response did not relapse. Patients who had received prior therapy with busulphan had a higher remission rate but a lower quality of cytogenetic response. Escalation of Roferon to 12 million units per day in relapsing or nonresponding patients induced PHR in 2/7. Neutralizing anti-interferon antibodies occurred in 7 relapsing or nonresponding patients. The cytoreductive induction with hydroxyurea enhanced the hematologic remissions to a median of 6 weeks. Further studies should define the role of combination therapy in order to improve response and prevent relapses.

Interferon alpha 2A in the treatment of chronic myelogenous leukemia in chronic phase. Results of the Spanish Group

Fifty-one patients with CML in chronic phase, less than two years after diagnosis, were included in one multicentric study aiming to assess the therapeutic value of interferon alpha 2a (IFN alpha 2a) in this setting. The therapeutic scheme was biphasic: The patients were first treated with hydroxyurea, and afterwards only received IFN alpha 2a, at a planned dose of 5MU/m2/day, s.c. Thirty-eight patients (81%) achieved an hematologic response, which was complete in 57% of the total group. The median time to response was of 42 days. In the last evaluation, a complete hematologic response was sustained in 21 patients (47%). Philadelphia suppression was obtained in 44% of the patients who achieved hematologic responses; major cytogenetic responses were obtained in 16% of the patients. The patients who obtained genetic responses were significantly younger and had a shorter interval from diagnosis to IFN than the patients who did not respond. At the moment of evaluation, 90% of the patients are alive, but the median follow-up of the series (217 days, range 21-1150) is too short to analyze any impact of IFN over survival. Six patients (12%) discontinued IFN because of toxicity, three of them because of severe flu-like syndrome. Leukopenia and thrombocytopenia were frequent, but rarely severe. Hypertriglyceridemia has been a very frequent finding.

Long-term treatment of chronic myelogenous leukemia with different interferons: results from three studies

131 patients with Philadelphia (Ph') chromosome positive chronic myelogenous leukemia (CML) were treated with interferon (IFN) alpha or a combination of IFN alpha and IFN gamma. In study, 1, 13 not pretreated and 41 pretreated patients, 48 in chronic phase disease, 6 in accelerated phase, received 4 x 10(6) U/m2 IFN alfa-2b initially. After achievement of hematologic remission, the individually minimum effective dose was used for maintenance. There was no response in acute phase disease. Of the 48 patients with chronic phase disease, 22 achieved a hematologic remission (HR), 13 a partial HR (PHR), and 13 did not respond (NR) to IFN. No major cytogenetic response occurred in these patients, but two patients achieved a major molecular response in Southern blots, whereas PCR tests were positive. In a further randomized study, CML patients without prior therapy were treated initially with 4 x 10(6) U/m2 IFN alpha alone (arm A) or in combination with 50 micrograms IFN gamma (arm B). For maintenance, the maximum tolerable dose of IFN alpha was given (up to 10 x 10(6) U/day). Thirteen patients in arm A (54%) and 14 (56%) patients in arm B achieved a HR, 7 patients (29%) in arm A and 6 patients (24%) in arm B a PHR. No response could be induced in 4 patients (17%) of arm A and 5 patients (21%) of arm B. Major cytogenetic responses were observed in 5 (20%) patients of arm A and 5 patients (20%) of arm B. Major molecular responses were observed in 3 patients of arm A and 5 patients of arm B.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Opposite sensitivity to the antiproliferative action of interferon-alpha and granulocyte-macrophage colony-stimulating factor in monoblastic U937 cells

Three variants of the human monoblastic cell line U937 with different degrees of sensitivity to the antiproliferative action of interferon-alpha (IFN-alpha were examined for phenotypic differences. The highly IFN-sensitive variant U937-V expressed twice as many IFN-alpha binding sites as both its IFN-alpha-resistant derivative U937-VR and the cell line U937 exhibiting a 20-fold reduction in IFN-alpha sensitivity as compared to U937-V cells. All three variants were IFN-reactive with regard to induction of 2',5'-oligoadenylate (2-5A) synthetase activity and were similarly sensitive to the growth-inhibiting action of IFN-gamma and tumor necrosis factor. Responsiveness to the antiproliferative effect of granulocyte-macrophage colony-stimulating factor (GM-CSF), however, was confined to cell lines U937 and U937-VR. Although expressing a comparable number of GM-CSF receptors, the highly IFN-sensitive variant U937-V was refractory to GM-CSF. Flow cytometry revealed a marked difference in the expression of the antigen CD11b which was detectable on 85% of cells of the U937-V line but only on approximately 25% of cells derived from the U937 and U937-VR lines. Results thus demonstrate opposite sensitivity of U937 cells to the growth-inhibiting action of IFN-alpha and GM-CSF, apparently dependent on the state of U937 differentiation as determined by expression of the CD11b antigen.

Characterization of anti-interferon-alpha antibodies appearing during recombinant interferon-alpha 2a treatment

Patients with malignant midgut carcinoid tumours received recombinant interferon-alpha 2a (rIFN-alpha 2a) or rIFN-alpha 2a and chemotherapy (streptozocin and doxorubicin) for 6 months, and then rIFN-alpha 2a alone. Antibodies, mainly of IgG type, binding to rIFN-alpha 2a developed in nine of 22 patients (41%), as determined by immunoassay. In seven patients, antibodies also neutralized the biologic (anti-viral) activity of rIFN-alpha 2a. Anti-IFN-alpha 2a antibodies were equally frequent in both sexes and treatment groups, but were not observed in those patients (n = 8) that had previously received other types of IFN. Antibodies appeared after a median of 6 months of rIFN-alpha 2a treatment and had a median duration of 6 months. The anti-IFN-alpha 2a antibody titres declined with time with no obvious relation to change of therapy, also during continued IFN-alpha 2a treatment. High titres of neutralizing antibodies appeared to impair anti-tumoural effects in individual potential responders. Anti-IFN-alpha 2a antibodies further examined in six patients bound to native IFN-alpha subtypes present in both allogenic and autologous leucocyte IFN-alpha. Such autoantibodies neutralized the biologic activity of autologous IFN-alpha in two patients, and in a third were partially neutralizing.

Low-dose alpha-interferon treatment of chronic myeloid leukemia

We treated 29 patients with chronic-phase and accelerated chronic myeloid leukemia (CML) with alpha-interferon in a dose of 2 mU/m2 given subcutaneously daily for 30 days and then three times per week. Most had received prior treatment. Three patients have had sustained hematologic and karyotypic remissions after a median of 22 months of treatment. Three further patients have had complete hematologic and partial karyotypic remissions. At a median follow-up of 48 months, the median survival has not been reached. This dose of alpha-interferon may induce sustained remissions even in pretreated patients and may prolong survival in CML.

Effects of tumour necrosis factor alpha on bone marrow aspirates of patients with acute myelogenous leukemia determined by flow-cytometric cell-cycle analysis

Tumour necrosis factor alpha (TNF alpha) exerts cytotoxic and antiproliferative effects on neoplastic cells. It has been used as a therapeutic agent for solid tumours and haematological malignancies. We report on the ex vivo determination of the effect of recombinant human rhuTNF alpha on bone marrow aspirates by a bromodeoxyuridine/propidium iodide method. Cell samples were drawn after 0.5, 2, 4, 6, 8, 10, 22, and 25 h from short-term suspension bone marrow cultures from patients with acute myelogenous leukemia (AML). Flow-cytometric cell-cycle analysis was performed after double DNA staining with propidium iodide and anti-BrdU antibodies. By this method the effect of rhuTNF alpha on cell proliferation can be evaluated after only 35 h. In about two-thirds of the bone marrow aspirates of AML an inhibiting effect on rhuTNF alpha can be demonstrated, developing to its full extent after 10 h.

Interferon alfa-2b in acute- and chronic-phase chronic myelogenous leukaemia: initial response and long-term results in 54 patients

Fifty-four patients with Ph1-positive chronic myelogenous leukaemia (CML) (48 with chronic-phase and six acute-phase disease) were treated with interferon alfa-2b subcutaneously (s.c.). The starting dose was 4 million units (MU)/m2 body surface area daily. It was reduced in parallel with serially determined leucocyte counts, and minimal effective doses were given as maintenance after achieving remission. Haematological remissions were induced in 22 of the 48 patients (46%) with chronic-phase disease. Thirteen patients (27%) revealed partial haematological remission and another 13 no response to treatment. No complete remission could be induced, although minor or partial cytogenetic responses were seen in 16 patients (33%). Moreover, a bcr-abl reduction was detected on Southern blot analysis in two patients. In chronic-phase disease, results of treatment were influenced by elapsed time after diagnosis, extent of previous treatment and interferon dosage. No beneficial effects of interferon were detected in the six patients with acute-phase disease. Principal acute side effects were fever and flu-like symptoms at the beginning of the therapy, which usually subsided within 3-7 days. Chronic side effects, especially weakness and neuropathy, were less frequent but more severe and necessitated discontinuation of treatment in 10 patients. In summary, interferon alfa-2b seems to be an effective treatment in early chronic-phase CML. Long-term effects on the course of the disease, however, must be determined.

Hairy cell leukaemia: the role of alpha interferon

Hairy cell leukaemia (HCL) is a chronic progressive disease of predominantly middle-aged men. Alpha interferon has been shown to induce significant responses in HCL patients. With interferon treatment the platelet count normalizes first, followed by the haemoglobin and neutrophil counts. The number of hairy cells in the bone marrow decreases and granulocytic, erythroid and megakaryocytic cells increase. Interferon is well tolerated with the most common side effect being a flu-like syndrome. A number of HCL patients will develop neutralizing antibodies and in these cases the chemotherapeutic agents pentostatin and 2-chlorodeoxyadenosine should be considered. Preliminary results with these agents are promising and further trials are ongoing to confirm their clinical promise.

A phase II study alternating alpha-2a-interferon and gamma-interferon therapy in patients with chronic myelogenous leukemia

Patients with Philadelphia chromosome-positive chronic myelogenous leukemia (CML) were treated with a combination of alpha-interferon and gamma-interferon. Recombinant alpha-2a-interferon (Roferon-A, Hoffmann-LaRoche, Inc., Nutley, NJ) and recombinant gamma-interferon (Genentech, Inc., South San Francisco, CA) were administered on alternating weeks each at doses ranging from 2 to 10 MU/m2 given intramuscularly. Of the 27 patients, 11 (41%) achieved complete hematologic remission (CHR) and 3 (11%) achieved partial hematologic remission (PHR). Responses were seen among 9 of 22 (41%) patients treated during the chronic phase of the disease and in 2 of 5 (40%) patients treated during the accelerated phase/second chronic phase. Cytogenetic responses were seen in six patients, including one complete response and five minor responses. Toxicities included flu-like symptoms, which appeared to be more severe with gamma-interferon than with alpha-interferon, hypertriglyceridemia, and thrombocytopenia. In this limited study, an improved outcome was not observed for the combination regimen compared with alpha-interferon alone.