Leukocyte-derived interferon (alpha) in human breast carcinoma. The American Cancer Society phase II trial

Harnessing the immune system in the battle against breast cancer

Breast cancer is the most prevalent malignancy in women and the second most common cause of cancer-related death worldwide. Despite major innovations in early detection and advanced therapeutics, up to 30% of women with node-negative breast cancer and 70% of women with node-positive breast cancer will develop recurrence. The recognition that breast tumors are infiltrated by a complex array of immune cells that influence their development, progression, and metastasis, as well as their responsiveness to systemic therapies has sparked major interest in the development of immunotherapies. In fact, not only the native host immune system can be altered to promote potent antitumor response, but also its components can be manipulated to generate effective therapeutic strategies. We present here a review of the major approaches to immunotherapy in breast cancers, both successes and failures, as well as new therapies on the horizon.

Antitumour actions of interferons: implications for cancer therapy

The interferons (IFNs) are a family of cytokines that protect against disease by direct effects on target cells and by activating immune responses. The production and actions of IFNs are finely tuned to achieve maximal protection and avoid the potential toxicity associated with excessive responses. IFNs are back in the spotlight owing to mounting evidence that is reshaping how we can exploit this pathway therapeutically. As IFNs can be produced by, and act on, both tumour cells and immune cells, understanding this reciprocal interaction will enable the development of improved single-agent or combination therapies that exploit IFN pathways and new 'omics'-based biomarkers to indicate responsive patients.

Beta interferon regulation of glucose metabolism is PI3K/Akt dependent and important for antiviral activity against coxsackievirus B3

An effective type I interferon (IFN)-mediated immune response requires the rapid expression of antiviral proteins that are necessary to inhibit viral replication and virus spread. We provide evidence that IFN-β regulates metabolic events important for the induction of a rapid antiviral response: IFN-β decreases the phosphorylation of AMP-activated protein kinase (AMPK), coincident with an increase in intracellular ATP. Our studies reveal a biphasic IFN-β-inducible uptake of glucose by cells, mediated by phosphatidylinositol 3-kinase (PI3K)/Akt, and IFN-β-inducible regulation of GLUT4 translocation to the cell surface. Additionally, we provide evidence that IFN-β-regulated glycolytic metabolism is important for the acute induction of an antiviral response during infection with coxsackievirus B3 (CVB3). Last, we demonstrate that the antidiabetic drug metformin enhances the antiviral potency of IFN-β against CVB3 both in vitro and in vivo. Taken together, these findings highlight an important role for IFN-β in modulating glucose metabolism during a virus infection and suggest that the use of metformin in combination with IFN-β during acute virus infection may result in enhanced antiviral responses.

IMPORTANCE

Type I interferons (IFN) are critical effectors of an antiviral response. These studies describe for the first time a role for IFN-β in regulating metabolism--glucose uptake and ATP production--to meet the energy requirements of a robust cellular antiviral response. Our data suggest that IFN-β regulates glucose metabolism mediated by signaling effectors similarly to activation by insulin. Interference with IFN-β-inducible glucose metabolism diminishes the antiviral response, whereas treatment with metformin, a drug that increases insulin sensitivity, enhances the antiviral potency of IFN-β.

Utilization of Interferon in Gynecologic and Breast Cancer

The usual treatment of gynecologic cancer has been surgery, chemotherapy and radiotherapy. New therapies are being developed to improve efficacy of treatment. Interferons are inducible secretory glycoproteins that have immunomodulatory, antiviral, anti-angiogenic and anti-proliferative effects. Their potential antitumor effect has been demonstrated in many studies. Some patients obtain beneficial effects; in other patients the treatment failure can occur. IFNs can modulate the immune response and inhibition of tumor angiogenesis. When any alteration in gene expression occurs, there is modulation of the receptors of other cytokines and enzymes that control cell function. These alterations can influence the differentiation, cell proliferation rate and apoptosis. The molecular mechanisms that control apoptotic cell death can be improved through cancer management using IFN in single, combination or adjuvant treatment. Malignant cells generally present defects in programmed cell death and apoptosis. Immunomodulation and angiogenesis inhibition are indirect antitumor mechanisms mediated by apoptosis. With regard to immunomodulation, IFNs can have antitumor effects through increases in cytotoxic T cells, natural killer cells and dendritic cells. Angiogenesis inhibition can result from endothelial cell apoptosis. This factor is important in inhibiting tumor genesis and forming metastases. The aim of this review is to discuss the role of Interferon in the treatment of gynecologic malignancies/breast cancer and mechanisms of action.

Review: Milstein Award lecture: interferons and cancer: where from here?

Interferons (IFNs) remain the most broadly active cytokines for cancer treatment, yet ones for which the full potential is not reached. IFNs have impacted positively on both quality and quantity of life for hundreds of thousands of cancer patients with chronic leukemia, lymphoma, bladder carcinoma, melanoma, and renal carcinoma. The role of the IFN system in malignant pathogenesis continues to enhance understanding of how the IFN system may be modulated for therapeutic advantage. Reaching the full potential of IFNs as therapeutics for cancer will also result from additional understanding of the genes underlying apoptosis induction, angiogenesis inhibition, and influence on immunologic function. Food and Drug Administration (FDA) approval of IFNs occurred less than 20 years ago; after 40 years, third-generation products of early cytotoxics, such as 5- fluorouracil (5FU), are beginning to reach clinical approval. Thus, substantial potential exists for additional application of IFNs and IFN inducers as anticancer therapeutics, particularly when one considers that their pleiotropic cellular and molecular effects have yet to be fully defined.

Interferon-Gamma and TRAIL in Human Breast Tumor Cells

Induction of apoptosis in tumor cells by death receptor activation is a novel therapeutic strategy. However, in systemic antitumor treatments, severe toxic effects have been observed with tumor necrosis factor-alpha (TNF-alpha) and CD95 ligand. TNF-alpha causes a lethal inflammatory response and CD95L produces lethal liver damage. Preclinical studies in mice and nonhuman primates showed no systemic cytotoxicity upon injection of recombinant TNF-related apoptosis-inducing ligand (TRAIL) at doses that effectively suppressed solid tumors such as colon and mammary carcinomas. Although unwanted effects of some TRAIL preparations have been reported in normal cells, these data suggest that TRAIL could be a suitable approach in cancer therapy. However, several mechanisms of resistance to TRAIL-mediated apoptosis have been described in tumor cells such as lack of TRAIL apoptotic receptors, enhanced expression of TRAIL-decoy receptors, and expression of apoptosis inhibitors. In combination regimes, interferon-gamma (IFN-gamma) could provide a promising antitumor therapeutic approach as it has been described to enhance cellular susceptibility to apoptosis in a variety of tumor cells. The mechanism by which IFN-gamma promotes cell death seems to be via the regulation of the expression of different proteins involved in apoptosis. Altogether, these data suggest a combination strategy to selectively kill tumor cells that need to be further explored.

Potential of interferon-alpha in solid tumours: part 2

The second part of this review examines the use of recombinant interferon-alpha (rIFNalpha) in the following solid tumours: superficial bladder cancer, Kaposi's sarcoma, head and neck cancer, gastrointestinal cancers, lung cancer, mesothelioma and ovarian, breast and cervical malignancies. In superficial bladder cancer, intravesical rIFNalpha has a promising role as second-line therapy in patients resistant or intolerant to intravesical bacille Calmette-Guérin (BCG). In HIV-associated Kaposi's sarcoma, rIFNalpha is active as monotherapy and in combination with antiretroviral agents, especially in patients with CD4 counts >200/mm(3), no prior opportunistic infections and nonvisceral disease. rIFNalpha has shown encouraging results when used in combination with retinoids in the chemoprevention of head and neck squamous cell cancers. It is effective in the chemoprevention of hepatocellular cancer in hepatitis C-seropositive patients. In neuroendocrine tumours, including carcinoid tumour, low-dosage (</=3 MU) or intermediate-dosage (5 to 10 MU) rIFNalpha is indicated as second-line treatment, either with octreotide or alone in patients resistant to somatostatin analogues. Intracavitary IFNalpha may be useful in malignant pleural effusions from mesothelioma. Similarly, intraperitoneal IFNalpha may have a role in the treatment of minimal residual disease in ovarian cancer. In breast cancer, the only possible role for IFNalpha appears to be intralesional administration for resistant disease. IFNalpha may have a role as a radiosensitising agent for the treatment of cervical cancer; however, this requires confirmation in randomised trials. On the basis of current evidence, the routine use of rIFNalpha is not recommended in the therapy of head and neck squamous cell cancers, upper gastrointestinal tract, colorectal and lung cancers, or mesothelioma. Pegylated IFNalpha (peginterferon-alpha) is an exciting development that offers theoretical advantages of increased efficacy, reduced toxicity and improved compliance. Further data from randomised studies in solid tumours are needed where rIFNalpha has activity, such as neuroendocrine tumours, minimal residual disease in ovarian cancer, and cervical cancer. A better understanding of the biological mechanisms that determine response to rIFNalpha is needed. Studies of IFNalpha-stimulated gene expression, which are now feasible, should help to identify molecular predictors of response and allow us to target therapy more selectively to patients with solid tumours responsive to IFNalpha.

Potential of interferon-alpha in solid tumours: part 1

Interferon-alpha (IFNalpha) is a pleiotropic cytokine with direct and indirect antitumour effects. These include prolongation of the cell cycle time of malignant cells, inhibition of biosynthetic enzymes and apoptosis, interaction with other cytokines, and immunomodulatory and antiangiogenic effects. The first clinical trials in solid tumours used crude preparations of natural IFNalpha and demonstrated that tumour regressions in solid tumours and haematological malignancies were possible. Since the advent of genetic engineering technology, recombinant (r) IFNalpha has been widely evaluated in solid tumours. This review discusses the use and potential of rIFNalpha in solid tumours; the first part focuses on malignant melanoma and metastatic renal cell carcinoma (RCC). In the adjuvant treatment of malignant melanoma, rIFNalpha has been tested in randomised trials in more than 6000 patients. High-dosage IFNalpha (> or =10MU) prolongs disease-free survival (DFS) but not overall survival (OS). Low-dosage IFNalpha (< or =3MU) has not been shown to prolong DFS or OS, and current data do not support its use outside clinical trials. The latest United Kingdom Co-ordinating Committee on Cancer Research meta-analysis of ten randomised trials that used adjuvant rIFNalpha has shown that there is a benefit in DFS but not OS. No conclusions can be reached for intermediate-dosage IFNalpha (5 to 10MU) until the mature results of the European Organization for Research and Treatment of Cancer (EORTC) study 18952 are available. In RCC, current evidence does not support the use of adjuvant IFNalpha. In metastatic malignant melanoma and RCC, reported response rates to rIFNalpha are approximately 15%. In a minority of responding patients, however, these responses can be long-standing. In metastatic malignant melanoma, IFNalpha combined with other cytotoxic agents with or without interleukin-2 has achieved high response rates but has not improved survival. In metastatic RCC, intermediate dosages of rIFNalpha should be used and therapy should probably be prolonged (>12 months); response depends on prognostic factors such as good performance status, whereas survival is affected by factors such as low tumour burden. Nephrectomy should therefore be considered in patients with good performance status prior to IFNalpha immunotherapy in advanced RCC, even in patients with metastatic disease. The toxicity of high-dosage IFNalpha and the lack of definite benefit on OS with high- or low-dosage IFNalpha do not support its use outside clinical trials. Data from the ongoing US Intergroup studies, the ongoing EORTC 18991 study (long-term therapy with pegylated IFNalpha) and mature data from EORTC 18952 (intermediate-dosage IFNalpha) will help establish the role of IFNalpha as adjuvant therapy in malignant melanoma.

Effect of interferon alpha-2a on hormone receptor status in patients with advanced breast cancer

The aim of this study was to assess the effect of recombinant interferon alpha-2a (rh-IFN) on estrogen (ER) and progesterone (PR) receptor expression in patients with advanced breast cancer and the evaluation of the effect of rh-IFN pretreatment on response to endocrine therapy with tamoxifen (TAM). Between June 1990 and November 1992, 20 patients with disseminated breast cancer and with metastatic skin nodules suitable for biopsy were entered into this study. Eighteen assessable patients underwent biopsy before and 2 weeks after treatment with rh-INF. rh-INF 3 x 10(6) IU were administered subcutaneously per day. Patients with ER expression at second biopsy were subsequently treated with 20 mg TAM daily. One patient had rapid disease progression and died before rebiopsy could be performed, and an additional patient refused second biopsy. All other patients were considered assessable. Thirteen patients showed ER expression before rh-IFN treatment, and 5 PR presented with expression. Rh-IFN increased ER expression in three patients and PR in four patients. No change was observed in 8 patients for ER and in 12 patients for PR. ER expression decreased in seven patients and PR expression decreased in two patients, respectively. Two patients showed a partial remission after subsequent treatment with TAM. Adverse reactions caused by rh-IFN were mainly flu-like symptoms. In this trial we found no systematic impact of rh-IFN on hormone receptor expression and, subsequently, on the response rate in patients with advanced breast cancer.

The immunology and immunotherapy of breast cancer: an update

Adenocarcinomas of the breast behave clinically and epidemiologically in ways that show host resistance factors are important for outcome in addition to grade and stage of malignancy. Immune reactivity to autologous tumors is indicated by the general presence of lymphoid infiltration (LI) and regional lymph node changes; however, these changes predict favorable outcome only in non-metastatic disease. LI is characterized by CD4+ and CD8+ tumor infiltrating lymphocytes reflecting latent cell-mediated immunity (CMI). CMI and humoral immune reactivity have been demonstrated to autologous tumor and a variety of tumor-associated antigens (TAA) have been implicated including CEA, HER-2/neu, MAGE-1, p53, T/Tn and MUC-1. Immune incompetence involving CMI is progressive with the stage of breast cancer and is prognostically significant. Immunotherapy of several types has been designed to address this immunodeficiency and the TAAs involved. Animal models have employed drug therapy, cytokine transfection, vaccines with autologous tumor, cytokines like interferon alpha (IFN-alpha) and interleukin-2 (IL-2), TAA tumor vaccines, and immunotoxins with evidence of tumor regression by immunologic means. Immunotherapy of human breast cancer is a rapidly growing experimental area. Positive results have been obtained with natural IFN and interleukins, particularly in combination strategies (but not with high dose recombinant IFN or IL-2), with autologous tumor vaccine (but not yet with transfected autologous tumor); with a mucin carbohydrate vaccine (Theratope) in a combination strategy (but not with mucin core antigen) and with several immunotoxins. Combination strategies involving immunorestoration, contrasuppression, adjuvant, and immunotoxins are suggested for the future.

Minimal residual disease in metastatic breast cancer: treatment with IFN-beta, retinoids, and tamoxifen

The aim of this pilot study was to investigate if chemotherapy (CT) followed by the combination of interferon-beta (IFN-beta), retinoids, and tamoxifen could be effective in the treatment of metastatic breast cancer (MBC). Thirty-six patients with stage IV carcinoma of the breast were treated with six courses of cyclophosphamide, 5-fluorouracil, 4-epidoxorubicin, vincristine, and prednisone every 3 weeks (FECPV), followed by two courses of non-cross-resistant drugs, methotrexate, mitomycin C, and mitoxantrone (MMM). Treatment was continued, in responders, with low dose IFN-beta, retinyl palmitate, and tamoxifen until relapse of the disease occurred. Among 36 evaluable patients, 23 achieved a clinical response (64 %) (95 % confidence interval [c.i.] 46 %-79 %), 7 had stable disease (19%), and 6 (17%) progressed. Leukopenia occurred in 15 patients, thrombocytopenia in 6, and anemia in 11. Sixteen patients had nausea/vomiting, stomatitis was observed in 9, and diarrhea occurred in 3. Toxicity from maintenance therapy was mild and mainly hepatic. Median response duration was 31 months (range 5-107). Median overall survival was 32 months (9-108). Our study shows that this combined approach for the treatment of MBC is feasible, with an acceptable toxicity.

Interferon-beta, retinoids, and tamoxifen in the treatment of metastatic breast cancer: a phase II study

Based on the additive or synergistic antiproliferative effect of interferon and tamoxifen on breast cancer cell lines and on preclinical and clinical data on retinoids alone and in combination with antiestrogen or interferon, we designed a pilot phase II study to test the toxicity of simultaneous administration of interferon-beta (IFN-beta), retinoids (R), and tamoxifen (TAM) and the efficacy of this combination as salvage therapy in a group of patients with metastatic breast cancer (MBC). A total of 49 stage IV breast cancer patients, 11 pretreated with hormones, 26 with chemotherapy, and 12 with both, received 30 mg TAM and two dose levels of IFN-beta and retinyl palmitate. Among 49 evaluable patients, 27 achieved a clinical response (55%; 95% CI 41-69%), 10 had stable disease (20%), and in 12 (25%) the disease progressed. Toxicity with both dose levels was moderate and mainly hepatic. Median response duration, not statistically different in estrogen receptor-positive and negative patients, was 31.4 months (range 4.9-67). Median overall survival was 19.2 months (range 2-69). We have shown that long-term administration of TAM, IFN-beta, and retinyl palmitate is feasible with moderate toxicity. We have also demonstrated that this regimen is active in pretreated MBC patients and that responses are not influenced by receptor status.

Megestrol acetate plus alpha 2a interferon as second line therapy for postmenopausal patients with advanced breast cancer: results of a multicentric phase II trial

This phase II study was aimed to evaluate the activity of a combination of megestrol acetate (MA) and alpha 2a interferon (IFN) in a group of tamoxifen-responsive breast cancer patients. Thirty patients with metastatic breast cancer either previously treated with adjuvant tamoxifen for at least 24 months or treated with tamoxifen for metastatic disease and showing an objective response or stability of disease, were given MA (single daily dose of 160 mg per os) and alpha 2a IFN (3 million units-MU-three times per week intramuscularly-i.m.-). Of the 29 evaluable patients, 2 (6.8%) achieved a complete response and 4 (13.8%) a partial response for an overall response rate of 20.6% (95% confidence limits = 5.9%-35.4%). Treatment toxicity was mild and no patient had to discontinue or delay the treatment due to IFN side effects. Our results seem to rule out that alpha 2a IFN is able to improve the activity of MA as second-line therapy in tamoxifen-responsive patients.

Interferon as adjunctive treatment for non-metastatic renal cell carcinoma

OBJECTIVE

To investigate the effect of recombinant alpha 2b-interferon therapy on natural killer (NK) activity and antibody-dependent cell-mediated cytotoxicity (ADCC) in the peripheral blood in patients with renal cell carcinoma who had undergone radical nephrectomy.

PATIENTS AND METHODS

Between January 1988 and June 1989, 20 patients (14 men and six women, mean age 59 years, range 43-80) received interferon (IFN) therapy following radical nephrectomy for renal cell carcinoma. Thirteen patients had stage I disease, one had stage II and six had stage III; none had metastases.

RESULTS

There was a significant increase in NK activity at 5 and 7 months after starting IFN therapy but there was no increase in ADCC.

CONCLUSIONS

Low doses of IFN administered long-term increased NK activity in patients with renal cell carcinoma. This finding should be helpful in designating protocols for randomized studies of post-operative IFN administration as adjuvant therapy.

Immune modulatory effects of immunoglobulins on cell-mediated immune responses in vitro

Intravenous Immunoglobulin (IVIG) at a concentration of 5 mg/ml, significantly inhibited mitogenic responses to phytohaemagglutinin (PHA), concanavalin A (conA) and pokeweed mitogen (PWM) by peripheral blood cells from healthy donors. No difference in inhibition by IVIG was seen when stimulating different T-lymphocyte cell subsets. Inhibition by IVIG was dose-dependent. An increased response was observed when IVIG was added more than 12 h after PHA compared to adding 1 h before [P = 0.05]. Intravenous immunoglobulin added to mixed lymphocyte cultures (MLC), reduced the median response by more than 60% (range 14-89%; P = 0.03) and almost completely abrogated the lymphocyte response to Staphylococcus aureus protein A (SPA), whose median inhibition was 94% (range 90-99%; P = 0.02). When comparing 12 different commercial IVIG preparations at a concentration of 2.5 mg/ml, the median inhibition of the PHA stimulation ranged from 4% to 35% and the MLC response from 0% to 66%. In the presence of IVIG the lymphocyte response to different herpes virus antigens was reduced by > 50%. No difference in inhibitory effect was seen when comparing IVIG and cytomegalovirus (CMV) hyper Ig, but CMV negative Ig resulted in lower inhibition [P = 0.05]. Three out of five IgG preparations (2.5 mg/ml) made from single donors inhibited PHA stimulation significantly more than commercial IVIG [P < 0.05]. Mean inhibition was 61% compared to 35%. Inhibition by pooled IgG from five donors was 56%. F(ab')2 fragments of IVIG inhibited the MLC response by more than 50% (range 34-75%), SPA stimulation by 97% (83-104%) and PHA stimulation by more than 30% (26-37%). One of two Fc preparations tested had an inhibitory effect, but the inhibition was less than that obtained with the F(ab')2 fragments [P = 0.04]. These results further strengthen the notion that IVIG exerts its immune modulatory effect by binding to leukocyte surface receptors. A clear inhibition was obtained with concentrations corresponding to the serum levels obtained when IVIG is given 250-500 mg/kg bodyweight. F(ab')2 fragments have the same inhibitory effect as intact IgG molecules but the role of Fc fragments still remains unclear. Differences in the immunosuppressive effect of various IVIG preparations may be associated with the method of preparation.

Lymphoblastoid interferon in advanced breast cancer: a phase II study

Thirty-two metastatic breast cancer patients entered a phase II study in order to evaluate the toxicity and the clinical activity of lymphoblastoid interferon (IFN). The treatment was divided into two phases, induction and maintenance. During the first, patients were submitted to lymphoblastoid IFN at the dose of 3 MU die intramuscularly for 4-8 weeks; during maintenance treatment IFN was given at the same dosage, intramuscularly, every other day until progression. Five patients with inadequate follow-up were excluded from disease evaluation, thus 27 patients were evaluable for response. No complete response was observed; one patient achieved a partial response and 15 patients disease stabilization. Median time to progression in patients with partial response or stable disease was 11 weeks (range 2-32). Five patients with soft tissue metastases were biopsied before and after 1-2 months of treatment in order to perform Labelling Index and hormonal receptor status determinations. No significant modification was observed.

Human recombinant interferon-beta SER and tamoxifen: growth suppressive effects for the human breast carcinoma MCF-7 grown in the athymic mouse

Tamoxifen is the endocrine treatment of choice for breast cancer. However, resistance to therapy and patient relapse inevitably occurs. In future treatment schedules, interferons could be administered with tamoxifen, in an attempt to prevent disease recurrence. Human recombinant interferon-beta SER (rIFN-beta SER) inhibited the growth in vitro of the estrogen receptor (ER) positive breast cancer cell line MCF-7 and the ER negative breast cancer cell line MDA-MB-231. This inhibitory effect was achieved at doses of 50 U/ml and above. The growth of MCF-7 tumors in estradiol-stimulated athymic mice was greatly inhibited by high dose rIFN-beta SER treatment (10(6)U/day). In spite of the impressive antitumor effects upon MCF-7 tumors, rIFN-beta SER had no effect upon ER levels within the tumors at either the RNA or protein level, as measured by Northern blotting and ER-EIA respectively. High dose rIFN-beta SER (10(6)U/day) did result in some inhibition in the growth in vivo of the tamoxifen-stimulated MCF-7 variant MCF-7 TAM, although not to the same extent as was observed with the estradiol-stimulated MCF-7 tumors. rIFN-beta SER was also administered to animals bearing MCF-7 tumors and treated with estradiol and tamoxifen. In the animals undergoing high dose therapy (10(6)U/day), tumor growth was completely suppressed. Furthermore, tumor growth continued to be suppressed in those animals in which the rIFN-beta SER therapy was halted and the tamoxifen capsule removed. No tumors were observed in spite of the environment of estradiol stimulation. Thus, the combination of interferon and tamoxifen was totally growth suppressive for MCF-7 xenografts in nude mice.

Tamoxifen and alpha interferon in advanced breast cancer

Thirteen pretreated advanced breast cancer patients received a combination of alpha interferon 5 million IU every 2 days, subcutaneously, plus tamoxifen 10 mg 3 times daily, until disease progression. The objective response rate was 15.4%: 1 patient achieved a complete response, 1 a partial response and 11 demonstrated stable disease; half of the patients were receptor negative and/or pretreated with hormonotherapy. Durations of response were 16 and 26 months for the CR and PR patients respectively; median progression-free survival was 4 months (range 0-26). Toxicities were registered according to WHO criteria: 4 patients stopped the treatment with interferon because of severe flu-like symptoms, while in the others the combination was generally accepted with good tolerance.

Phase II evaluation of interferon added to tamoxifen in the treatment of metastatic breast cancer

This phase II trial evaluated the clinical role of interferon (IFN) in overcoming tamoxifen (TAM) resistance in breast cancer. Twenty women and 1 man received recombinant alpha interferon (5 million units per meter squared intramuscularly, 5 times per week) plus TAM (10 mg orally, twice daily) for the treatment of metastatic breast cancer, either after failing tamoxifen therapy or as frontline hormonal therapy. Of the 9 evaluable patients with disease progression after an objective response to TAM, there were no partial or complete responses with the addition of IFN. Ten evaluable patients received TAM plus IFN as frontline hormonal therapy with 2 complete and 3 partial responses for an overall response rate (RR) of 50% (95% confidence interval = 19-81), a 71% RR for ER-positive patients (95% confidence interval = 29-96) and no responses in ER-unknown patients. Sixteen patients required dose reductions of IFN and 8 patients discontinued therapy due to toxicity. It is unlikely that the RR for TAM plus IFN is greater that than seen with TAM alone, or that the addition of IFN to TAM therapy can overcome clinical TAM resistance.

CD8+ suppressor cells inhibit staphylococcal protein A-induced gamma interferon production by CD4+ lymphocytes

We have previously demonstrated that purified soluble staphylococcal protein A (SpA) induces the synthesis of gamma interferon (gamma-IFN) by human peripheral blood lymphocytes (PBL), that CD4+ (T helper) cells represent the subpopulation responsible for this synthesis and that prostaglandin E2 (PGE2)-activated CD8+ (T suppressor/cytotoxic) cells have an inhibitory effect on this synthesis. The mechanisms implicated in this regulation remain to be defined, and could involve direct cell-to-cell contact among members of these subpopulations or may be due to a soluble mediator release by CD8+ suppressor cells. In this study, we explored the ability of PGE2 to activate CD8+ cells into either cytotoxic or suppressor cells and the mechanisms by which these cells regulate the SpA-induced gamma-IFN production by CD4+ cells. Peripheral blood lymphocytes from 18 healthy volunteers, prepared by centrifugation over Ficoll-Hypaque gradient, were separated into subpopulations by passage on nylon wool columns and selective depletion using specific monoclonal antibodies and rabbit complement. CD4+ cells were incubated with SpA for gamma-IFN production and CD8+ cells were incubated with 10(-6) M PGE2. After 48 h these populations were remixed and the cytotoxic or suppressor effector function of CD8+ cells was measured. No cytotoxic activity was detected against CD4+ cells. Different levels of suppression of gamma-IFN production were observed in our subjects. Suppression mediated through the release of soluble factor was observed in only 2 of the 18 cases. Taken together, these results suggest that in the present experimental system, the regulation of gamma-IFN production is mediated by suppressor CD8+ T cells and that cell-to-cell contact between both subpopulations is usually necessary.

Biological and clinical effects of interferon-beta ser at two doses

To assess biological response, therapeutic activity, and side effects, a randomized, double-blind trial of two doses of interferon-beta ser (IFN-beta ser), differing by 20-fold 4.5 and 90 x 10(6) units), was undertaken in 64 patients with metastatic renal carcinoma. Patients were treated intravenously with injections daily for 10 days with an 11-day rest before treatment was reinitiated. The trial confirmed the relatively good toleration of IFN-beta ser; in the first cycle only 4/63 patients had anorexia of moderate or greater severity. Median weight change over the duration on study was -1.5 kg; in the first cycle only 7% of patients had performance status decline greater than 1 level. Statistically significant changes (p less than 0.05) occurred in granulocytes, lymphocytes, calcium, cholesterol, alkaline phosphatase, and aspartate transferase (AST); however, except for AST, overall clinical differences in the two doses were not great. Of 60 patients evaluated, 1 developed neutralizing antibody. When assessed 24 h after IFN-beta ser at 4.5 x 10(6) units, significant (p less than 0.05) augmentation had occurred in beta 2-microglobulin, HLA-DR, and HLA-DQ expression on monocytes, 2',5'-oligoadenylate (2-5A) synthetase in peripheral mononuclear cells, and natural killer (NK) and K cells functional activity. Although the 90 x 10(6) unit dose also resulted in stimulation of these responses, little additional augmentation of biological response occurred at the higher dose. Except for a decline in monocyte HLA-DR expression, biological responses remained increased at both doses over the 10-day period of treatment. However, no objective regressions of metastatic disease occurred. In view of objective responses in metastatic renal carcinoma in other trials with IFN-beta ser, consideration should be given to alternative schedules.

Biological response modifiers in the management of patients with breast cancer

Despite impressive progress in understanding the biology of breast cancer, mechanisms of host defense, and the pathophysiology of the metastatic process, this burgeoning fact bank has made little impact on the management of patients with breast cancer. There are many interesting ideas for improved diagnosis and therapy in various stages of development, but few have actually translated into improved survival of patients with breast cancer. Potentially useful biological agents include cytokines, monoclonal antibodies, immunotoxins, vaccines, and adoptive cellular therapies. Therapies targetting growth factor receptors and the cellular machinery required for metastasis may become useful, especially when used in combination with other cytotoxic agents. Colony-stimulating factors may allow a test of the hypothesis that augmented dose-intensity of cytotoxic chemotherapy will cure more patients. Though we are not yet sure precisely how to use all of these new tools, there can be little doubt that their application will make a significant impact on the management of patients with breast cancer and other malignancies in the next decade.

Inhibition of hormone-dependent and independent breast cancer cell growth in vivo and in vitro with the antiestrogen toremifene and recombinant human interferon-alpha 2

The antiproliferative action of the antiestrogen toremifene and recombinant human interferon-alpha 2a (IFN-alpha 2a) were examined on human breast cancer cell lines grown in culture and in the athymic mouse. Solid tumors grew from an inoculation of a 99:1 ratio of hormone dependent (MCF-7) and hormone independent (MDA-MB-231) breast cancer cells without estrogen administration. However, estradiol supplementation significantly increased the rate of tumor growth. The daily administration of 1.35 x 10(6) U of recombinant human IFN-alpha 2a resulted in a marked rduction of tumor growth in both estradiol-treated and non-treated mice. Toremifene administration (130 micrograms/day from a sustained release preparation) markedly inhibited estradiol stimulation of mouse uterine weight and partially reduced estradiol-stimulated tumor growth. The combination of IFN-alpha 2a (1.35 x 10(6) u/day) with toremifene (130 micrograms/day) reduced estradiol-stimulated growth much below that of toremifene alone but not below that seen with interferon alone. Toremifene (10(-10)-10(-6) M) did not inhibit the growth of hormone-independent MDA-MB-231 breast cancer cells in vitro whereas it did inhibit the growth of hormone-dependent MCF-7 cells in phenol red containing media. IFN-alpha 2a (1-10,000 u) inhibited the growth of both MCF-7 and MDA-MB-231 cells in culture; however, MCF-7 cells were approximately 10-fold more sensitive to interferon inhibition. This was consistent with the MCF-7 cells showing a greater sensitivity to interferon than MDA-MB-231 cells in the induction of 2'5'-oligoadenylate synthetase.(ABSTRACT TRUNCATED AT 250 WORDS)

Lymphokines and cytokines as cancer treatment. Immunotherapy realized

Human proteins with identified effects on host responses to malignant cells have been established as effective therapeutic techniques in cancer. Lymphokines, products of activated cells of the immune system, have pleiotropic biochemical and cellular effects. These include stimulation of immune effector cell proliferation, augmentation of cytotoxicity of immune effector cells for tumor cell targets, enhancement in antigen-recognition potential by monocytes, and modulation of tumor-associated antigen expression on neoplastic cells. Interferons (IFN) and interleukin-2 (IL-2), purified to homogeneity, can induce regression of metastatic malignancy. Recombinant DNA technology has facilitated large-scale production of these and other lymphokines and cytokines. It has also made possible analyses of physical structures of the molecules themselves and has enabled creation of mutated molecules with specific, desired substitutions in their amino acid sequence. Monoclonal antibodies, directed at tumor-associated antigens, can augment antibody-dependent cell-mediated cytotoxicity and can selectively deliver cytotoxic techniques to malignant cells. Molecules that modify the host resistance to malignant disease also have potential to augment effectiveness of other cancer treatment techniques. Lymphokines, cytokines, and monoclonal antibodies, all products of biotechnology, have resulted in fulfillment of the promise of the immune system for inhibition of growth of human malignancy.

Induced proteins in human peripheral mononuclear cells over a range of clinically tolerable doses of interferon-gamma

This study assessed biologic response modification at three different dose levels (0.15, 1.5, and 15 mg/m2) of interferon-gamma (IFN-gamma) administered by intravenous bolus three times weekly. A final total of 24 patients were evaluable. Dose-limiting toxicity occurred at the highest dose level (15 mg/m2) and included fatigue, leukopenia, and hepatotoxicity. Evaluation of biologic response modification included assessment of 2',5'-oligoadenylate (2-5A) synthetase activity in peripheral mononuclear cells, measurement of serum beta 2-microglobulin and expression of beta 2-microglobulin on monocytes, measurement of monocyte HLA Class II expression (HLA-DR, HLA-DQ), and measurement of hydrogen peroxide generation by monocytes 24 h after the first and fourth IFN-gamma treatments. Significant increases (p less than 0.05) from baseline were seen at 24 h with all parameters except H2O2 generation. Except for enhancement of HLA-DR, even the lowest dose (0.15 mg/m2) augmented synthesis of 2-5A synthetase and HLA proteins. A dose-response effect was noted for changes in serum and monocyte beta 2-microglobulin levels but not for 2-5A synthetase levels or HLA Class II antigen expression on monocytes. After 4 doses administered over 9 days, most parameters remained increased when compared to pretreatment, but were not further enhanced when compared with levels attained after the first dose. The results of this study document the efficacy of IFN-gamma for biological activation over a wide dose range and are consistent with the postulate that immunoregulatory effects of biological therapeutics can be obtained in man at doses substantially less than those that are maximally tolerated. Further documentation of biologic response parameters by IFN-gamma at low doses will be necessary to determine the importance of biologic activation in relation to antitumor activity.

Interferons: biological and clinical effects

Interferons play a key role in the immune system as biological response modifiers. Interferons alpha, beta, and gamma have been characterized, their nucleotide sequences defined, and the proteins produced by recombinant DNA technology. The myriad actions of interferons include enhancement of natural killer cell activity and antigen expression, induction of varied proteins, activation of macrophages, and antiviral, antiproliferative and antitumor effects. Clinical trials have demonstrated efficacy of interferons in some malignancies and ongoing studies are investigating results of combinations with other biological response modifiers and cytotoxic agents.

Recombinant human leukocyte interferon modulates neutrophil function in vitro

Recombinant human interferon-alpha 2 (rIFN-alpha A) was evaluated as a modulator of neutrophil functions. Neutrophils treated with rIFN-alpha A for 1 h in vitro showed reduced chemiluminescence (CL) and aggregation in response to phagocytosis. In contrast, when certain soluble stimuli [f-met-leu-phe (fMLP) or leukotriene B4] were used, rIFN-alpha A treatment conferred a doubling of CL. This was paralleled by a similar increase in superoxide anion production and a 56% increase of release of beta-glucuronidase and lysozyme. The NBT test showed that IFN treatment did not increase the number of responding neutrophils. However, there was a significant increase in the displaceable binding of fML[3H]P. Enzyme release, aggregation, and CL in response to other soluble stimuli, the ionophore A23187 and phorbol myristate acetate were unaffected by IFN treatment. Likewise, chemotaxis was not affected. Thus, phagocytosis-associated events and aggregation were hampered by rIFN-alpha A whereas secretory responses to receptor-dependent soluble stimuli were augmented. The mechanism for the latter is most likely dependent on the observed modulation of binding of fMLP to its receptor.

Treatment of advanced renal cell cancer with recombinant interferon alpha as a single agent and in combination with medroxyprogesterone acetate. A randomized multicenter trial

The response rates in metastatic renal cell cancer (RCC) after chemotherapy, hormonal treatment, or immunotherapy rarely exceed 15%. Recently, interferon alpha (IFN alpha) was used for treatment of this disease in several studies which also demonstrated response rates of 15%. In order to test whether IFN therapy combined with hormones would result in higher response rates we compared single agent IFN therapy with a combined therapy of rIFN alpha 2C plus medroxyprogesterone acetate (MPA) in a randomized multicenter trial. The rIFN alpha 2C (2MU) was given s.c. 5 times per week for 8-12 weeks and subsequently once weekly until week 48. In the combined treatment, 750 mg MPA was given p.o. daily until week 48 in addition to the IFN as described. The overall response rate in 93 evaluable patients was 5.4% corresponding to 2 complete and 3 partial responses. Median survival was 7 months in both treatment groups. These data confirm the ineffectivity of low IFN doses for treatment of RCC. The low response rate is not increased by addition of MPA to IFN. The analysis of other IFN studies suggests that not only IFN doses but also IFN sources may influence response rates in metastatic RCC.

Alpha-interferon treatment for adult T cell leukemia: low levels of circulating alpha-interferon and it's clinical effectiveness

We describe a patient with adult T cell Leukemia to whom alpha-interferon therapy was highly effective. Although a combination chemotherapy (ACVP) first introduced was effective in reducing total leukocyte counts, the percentage of leukemic cells relative to total leukocyte counts was decreased first after the institution of alpha-interferon therapy. The patient is now under complete remission for four years. It was noted in this patient that circulating alpha-interferon, measured by a sensitive radioimmunoassay, was consistently low as compared with the value found in the age-, sex-matched healthy control (p less than 0.001). Since adult T cell leukemia is pathogenetically related to the retrovirus infection, low levels of circulating alpha-interferon of the patient may be important from both pathogenetic and therapeutic standpoints. Alpha-interferon therapy may be an useful additive for the chemotherapy of adult T cell leukemia.

Human lymphoblastoid interferon does not increase survival when added to mitozantrone in the treatment of hepatocellular carcinomas

Human lymphoblastoid interferon, in an initial dose of 2.5 MU m-2 weekly i.m., was given with mitozantrone 12 mg m-2 i.v. every 3 weeks to 15 patients with hepatocellular carcinoma. The survival curve for these patients was worse than that of 15 patients previously treated with mitozantrone alone; there were more long-term survivors in those not given interferon; more side-effects were seen in the group given interferon. The addition of interferon to mitozantrone in the management of hepatocellular carcinoma is not recommended.

Diminished responsiveness of male homosexual chronic hepatitis B virus carriers with HTLV-III antibodies to recombinant alpha-interferon

In a randomized controlled trial, 41 chronic hepatitis B virus carriers were allocated, by opening numbered computerized randomization envelopes, to receive recombinant interferon-alpha 2A at three different doses: 2.5; 5.0, and 10.0 mU per m2. Thirty-two patients received treatment (6 for 3 months, 26 for 6 months), and 9 patients were controls (received no treatment). Ninety-three per cent of our patients were homosexual, and 41% had anti-HTLV-III in their serum. None of the control patients lost HBeAg. In contrast, six of the anti-HTLV-III-negative patients (33%) responded to treatment (p less than 0.02): five of these responders were homosexual (p less than 0.05). The response rate was greatest (44%) in the anti-HTLV-III-negative patients who received 10 mU per m2 of recombinant interferon-alpha 2A. None of the anti-HTLV-III-positive patients responded to treatment. The percentage reduction of hepatitis B virus DNA was significantly less in the anti-HTLV-III-positive group in comparison to the anti-HTLV-III-negative group at 1 and 4 months of treatment and at 3 months after the end of treatment (p less than 0.05). These patients were younger (33 vs. 42 years, p less than 0.02), had lower mean baseline AST values (42 vs. 80 IU per liter, p less than 0.02) and tended to have milder histological disease. Homosexual men with HBeAg-positive chronic liver disease who are anti-HTLV-III-positive appear to be less responsive to the direct antiviral and immunomodulatory effects of recombinant interferon-alpha 2A. This may be due to the subclinical immunosuppressive effects of co-infection with HTLV-III.

Immunotherapy of metastatic renal cell carcinoma with polyinosinic-polycytidylic acid

Polyinosinic-polycytidylic acid, a double-stranded ribonucleic acid that is a potent inducer of interferon production, was used in a stabilized form to treat 11 patients with metastatic renal cell carcinoma. Seven patients completed a full course of 8 infusions at maximum tolerated dosage. All patients experienced transient fever and marked fatigue. Anorexia was mild. Transient leukopenia occurred in 3 patients and reversible elevation in creatinine was observed in 1. All 4 patients with brain metastases became lethargic, and 3 died during or shortly after therapy. Only 2 patients demonstrated measurable total regression of isolated metastases (pleural/pulmonary in 1 and bone in 1) but in both metastases at other sites progressed. No partial regressions were seen. Metastases at all other sites (liver, brain and renal fossa) progressed during therapy. Patients who appeared to respond and who performed best during therapy generally demonstrated a higher performance status initially. Expression of natural cytotoxicity in in vitro testing did not correlate with a demonstrated response to treatment.

Effect of interferon alpha, interferon beta, and interferon gamma on the in vitro growth of human renal adenocarcinoma cells

Interferon-alpha, interferon-beta, and interferon-gamma differ in their antiproliferative effects for several cell lines. Interferons were thus assessed for their activity in inhibiting proliferation of three renal cell carcinoma cell lines. The malignant epithelial phenotype of each of these cell lines was confirmed by electron microscopy, histology, karyotype and tumorigenicity. When compared on an anti-viral unit basis, naturally produced interferon-beta was more effective than natural interferon-alpha for all cell lines and clones. Proliferation of each of the cell lines was inhibited by interferon-gamma. In all cases, removal of interferons from culture media resulted in resumption of the rate of cell growth after a variable delay of 6-10 days. If the antiproliferative effects of interferons predominate in mediating tumor regression, clinical response may depend upon the type of interferon to which the tumor is exposed.

Interferon-beta treatment of metastatic prostate cancer

A limited clinical trial of Interferon-beta (Human Fibroblast Interferon) in the treatment of advanced, hormone-refractory prostate cancer was conducted by the National Prostate Cancer Project (NPCP Protocol 2100). Sixteen patients with metastatic prostate cancer who had failed prior hormone therapy were entered into the study. Treatment consisted of 6 X 10(6) units of Interferon-beta intravenously three times per week for 12 weeks. Chills and fever were seen in ten of the 16 patients (62.5%), and mild hematologic toxicity occurred in four patients. No complete or partial responses were observed. Three patients had stable disease by NPCP criteria for a mean duration of 6.3 months. Progression of disease was seen in 13 of the 16 patients, eight of whom progressed during therapy. The results of this study suggest that Interferon-beta has limited efficacy in the treatment of advanced, hormone-refractory prostate cancer.

Recombinant gamma interferon in advanced breast cancer: a phase II trial

Fifteen patients with advanced carcinoma of the breast who had failed prior chemotherapy, were treated with recombinant gamma interferon at a dose of 2mg/m2 (1mg = 2.4 X 10(7) international units) intravenously for five consecutive days every other week. The median patient age was 51 and all patients had a performance status of 0-2 (Karnofsky greater than or equal to 50). Thirteen patients had two or three sites of metastatic disease and seven were estrogen receptor positive. No complete or partial responses were noted. Although some patients had brief periods of stable disease, almost all patients progressed after one or two courses. Only one patient was able to receive six courses of induction therapy and a brief course of maintenance. Flu-like symptoms and nausea were seen in all patients; vomiting and anorexia were frequent. Hepatic toxicity manifested by enzyme elevation was common and was most severe in patients with liver metastases. In this study a highly purified biologically active gamma interferon was not associated with anti-tumor activity in previously treated women with metastatic breast cancer.

The antitumor effects of interferon

Interferons show antitumor activity in patients with various malignancies. The mechanism(s) of the antitumor effects are not altogether clear. In one experimental animal model discussed herein, mice were injected with Friend erythroleukemia cells and treated with mouse interferon alpha/beta. The results suggest that interferon does not act directly on the tumor cells but acts via host mechanisms that are still ill defined.

Interferon in the treatment of cancer

Potential mechanisms of action of interferon in the treatment of cancer are suggested, followed by a discussion on the responsiveness of tumors to alpha-interferon.

Synergistic antiproliferative effect of human interferons in combination with mismatched double-stranded RNA on human tumor cells

Four human tumor cell lines were studied for their response to antiproliferative effects of various interferons (IFNs) alone and in combination with the novel mismatched dsRNA, r(I)n r(C12,U)n (Ampligen). RT4 cells (bladder carcinoma) were resistant to Ampligen alone, while A2182 (lung carcinoma), HT 1080 C14 (fibrosarcoma) and RT112 (bladder carcinoma) cells were inhibited in a dose-dependent manner. In contrast, RT4 cells were sensitive to the antitumor effects of IFNs as were HT1080 C14 and RT112 cells, while A2182 cells were resistant. In 3 of 4 cell lines, the recombinant IFNs were less effective than the corresponding natural IFNs when compared by analysis of variance on an IRU/ml basis over a range of concentrations. In all cell lines, a synergistic antiproliferative effect was seen with all IFN preparations studied in combination with Ampligen, as calculated by the isobole method according to Berenbaum (1981). The antiproliferative effect of IFN was potentiated greater than 3.3- to greater than 250-fold, depending on the cell lines, IFN, and concentrations used. Varying the concentration of beta ser-IFN while holding the Ampligen concentration constant gave synergy at all of the physiologically achievable concentrations tested in RT4 cells. These results indicate that: Ampligen worked synergistically with all IFNs in all cell lines studied; growth inhibition of cells resistant to IFNs can be potentiated by low doses of Ampligen; the antiproliferative effect of IFNs can be potentiated by Ampligen in Ampligen-resistant cells; and Ampligen may work by a mechanism other than, or in addition to, the induction of IFNs.

Biological therapy of cancer

Interferons and monoclonal antibodies are among the most promising biological approaches to cancer treatment which have so far been investigated. Both natural and recombinant interferon-alpha preparations have shown activity in a number of trials in hematologic malignancies, even in previously treated patients; activity in solid tumors, however, has been limited. Unconjugated monoclonal antibodies have been safely administered in several small trials and have had therapeutic value on occasion. In spite of a number of remaining problems and questions, monoclonal antibodies and their conjugates seem likely to find a number of distinct roles in cancer treatment; elimination of micrometastases and purging of bone marrow for grafting may be among these roles.