A phase II study of recombinant interleukin-2 with or without recombinant interferon-beta in non-Hodgkin's lymphoma. A study of the Cancer and Leukemia Group B

CpG oligodeoxynucleotides as TLR9 agonists: therapeutic applications in cancer

Toll-like receptors (TLRs) are part of the innate immune system, and they belong to the pattern recognition receptors (PRR) family. The PRR family is designed to recognize and bind conserved pathogen-associated molecular patterns, which are not generated by the host and are restricted and essential to micro-organisms. TLR9, which recognizes unmethylated CpG (cytosine guanosine dinucleotide), is a very promising target for therapeutic activation. Stimulation of TLR9 activates human plasmacytoid dendritic cells and B cells, and results in potent T helper-1 (T(h)1)-type immune responses and antitumor responses in mouse tumor models and in patients. Several pharmaceutical companies, such as Pfizer, Idera, and Dynavax, are developing CpG oligodeoxynucleotides (ODNs) for the treatment of cancer, along with other conditions, such as infections and allergy. CpG ODNs have shown promising results as vaccine adjuvants and in combination with cancer immunotherapy. Several TLR9 agonists are being developed and have entered clinical trials to evaluate their safety and efficacy for the treatment of several hematopoietic and solid tumors. In this review, we discuss the use of CpG ODNs in several phase I and II clinical trials for the treatment of NHL, renal cell carcinoma, melanoma, and non-small cell lung cancer, either alone or in combination with other agents.

Oligodeoxynucleotide CpG 7909 Delivered as Intravenous Infusion Demonstrates Immunologic Modulation in Patients With Previously Treated Non-Hodgkin Lymphoma

Oligodeoxynucleotides containing CpG motifs (CpG ODN) can alter various immune cell subsets important in antibody therapy of malignancy. We undertook a phase I trial of CPG 7909 (also known as PF-3512676) in patients with previously treated lymphoma with the primary objective of evaluating safety across a range of doses, and secondary objectives of evaluating immunomodulatory effects and clinical effects. Twenty-three patients with previously treated non-Hodgkin lymphoma received up to 3 weekly 2-hour intravenous (IV) infusions of CPG ODN 7909 at dose levels 0.01 to 0.64 mg/kg. Evaluation of immunologic parameters and clinical endpoints occurred for 6 weeks. Infusion-related toxicity included grade 1 nausea, hypotension, and IV catheter discomfort. Serious adverse hematologic events observed more than once included anemia (2=Gr3, 2=Gr4), thrombocytopenia (4=Gr3), and neutropenia (2=Gr3), and were largely judged owing to progressive disease. Immunologic observations included: (1) The mean ratio of NK-cell concentrations compared with pretreatment at day 2 was 1.44 (95% CI=0.94-1.94) and at day 42 was 1.53 (95% CI=1.14-1.91); (2) NK activity generally increased in subjects; and (3) Antibody-dependent cellular cytotoxicity activity increased in select cohorts. No clinical responses were documented radiographically at day 42. Two subjects demonstrated late response. We conclude CpG 7909 can be safely given as a 2-hour IV infusion to patients with previously treated non-Hodgkin lymphoma at doses that have immunomodulatory effects.

Immunotherapy in conjunction with autologous and allogeneic blood or marrow transplantation in lymphoma

Relapse is the major obstacle for successful transplantations in lymphoma. One of the ways to reduce relapse rates is to intensify immune-mediated effector mechanisms. Graft-versus-lymphoma may be achieved either by administration of cytokines or by allogeneic cell-mediated adoptive immunotherapy. The use of allogeneic non-myeloablative stem cell transplantation (SCT) is another option which may be applicable to all age groups. It remains to be seen whether non-myeloablative SCT will result in a lesser degree of relapse and higher disease-free survival in lymphoma patients.

Relationships between susceptibility to LAK cell-mediated lysis, conjugate formation and expression of adhesion molecules in B-cell derived non-Hodgkin's lymphomas

Adoptive immunotherapy with LAK cells has been investigated for the treatment of B-cell-derived lymphomas, but only a few significant tumor regressions were obtained. In order to explain this refractory state, the sensitivity to normal LAK-mediated lysis of 30 non-Hodgkin's lymphoma (NHL) malignant B-cells was determined using flow cytofluorimetry. A large heterogeneity was found, and we report a close correlation (p < 0.001) between the extent of lysis of malignant B-cells and their ability to form conjugates with LAK cells; which is the first step in LAK-mediated cytolysis. The levels of expression of HLA class I molecules, LFA-1 (CD11a/CD18), CD54 and CD58 were also studied and found to be expressed very heterogeneously. CD54 expression on malignant B-cells plays a major role in the initial conjugate formation with LAK cells (p < 0.001), and this was confirmed by inhibition experiments. Our results suggest that a weak expression of CD54 could constitute one mechanism by which NHL tumor B-cells escape natural immune surveillance and resist LAK cells immunotherapies.

Immunotherapy With Recombinant Human Interleukin-2 and Recombinant Interferon-α in Lymphoma Patients Postautologous Marrow or Stem Cell Transplantation

Immune-mediated effects appear to play a major role in controlling minimal residual disease (MRD). We, therefore, investigated the role of recombinant human interleukin-2 (rIL-2) given concomitantly with interferon-α (IFN-α) in malignant lymphoma (ML) patients with responding disease following autologous bone marrow or blood stem cell transplantation (ABSCT). Fifty-six patients were included in this investigation. Thirty-two patients had non-Hodgkin's lymphoma (NHL) and 24 patients had Hodgkin's disease (HD). Sixty-one patients (NHL 36, HD 25) served as historical controls. Patients from both groups had similar demographic characteristics, the same stage of disease at presentation, status of disease at transplantation, conditioning regimens, and type of transplant. rIL-2 and IFN-α were selfadministered in two cycles beginning 2.5 to 10.5 months (median, 4 months) posttransplant and separated by a 4-week interval. Each cycle consisted of IFN-α subcutaneously (SC) 3 × 106 U/d × 5 d/wk combined with rIL-2 SC 3 to 6 IU/m2/d × 5 d/wk for 4 weeks. The incidence of survival and disease-free survival (DFS) was significantly higher in the group under investigation than in the historical controls (P < .01). Of 56 patients with ML treated with IFN-α + rIL-2, 45 patients are DFS (80.4%) after a follow-up of 7 to 78 months (median, 34 months), whereas in the historical controls, 32 of 61 (52.5%) patients are disease free, in a follow-up of 4 to 84 months (median, 23 months) posttransplant (P < .01). Our preliminary results are encouraging and suggest that home administered immunotherapy with IFN-α and rIL-2 is relatively well tolerated and may intensify remission in ML patients with MRD following ABSCT.

In vivo biological response following low-dose interleukin-2 in complete remission B-cell non-Hodgkin's lymphoma patients. Italian Lymphoma Study Group (GISL)

The aim of the present study is to verify whether recombinant interleukin-2 (rIL-2) at low doses is well tolerated in aggressive lymphoma in complete remission (CR), and if there may be a biological justification for its use as a remission-maintenance therapy able to reduce the percentage of relapses. We treated 6 patients with B-cell non-Hodgkin's lymphoma (B-NHL) in CR following PM-Cytabom with rIL-2 3 IMU s.c. x 5 d per wk, every other wk for 8 wk. Our results show that this treatment provokes statistically significant changes in the absolute number of lymphocytes, eosinophils, CD25+ and CD122+ cells and soluble IL-2 receptors; these doses, however, are not sufficient to modify CD3+, CD16+ and CD56+ cell values or natural killer and lymphokine activated killer cell activity. Thus these findings do not appear to constitute a biological rationale for the use of rIL-2 at this dose and schedule as a remission-maintenance therapy in B-cell NHL. Nevertheless, the results are a valid basis for further study of the use of the same rIL-2 doses for a longer period of time in combination with other cytokines, in the hope that the biological effects can be augmented without increasing the toxic side effects.

Role of interleukin-2 in human hematological malignancies

Clinical studies with Interleukin-2 (IL-2) in human hematologic malignancies were initiated in the late 1980s. Based on clinical studies on various solid tumors, and laboratory research on hematopoietic cells, IL-2 was shown to be effective in 150 acute myeloid leukemia (AML) patients mainly for maintenance therapy in first complete remission, or with residual blast cells in the marrow. IL-2 has also been shown to be effective in remission induction in 10 patients with chronic myeloid leukemia (CML). The role of IL-2 in lymphoma patients remains to be established. IL-2 alone or in combination with Interferon-alpha, may intensify remission and prolong disease-free survival when given post autologous bone marrow transplantation (BMT) to patients with lymphoma and myeloid leukemia, and to a lesser degree, to patients with acute lymphatic leukemia (ALL). IL-2 in combination with HLA-matched or mismatched peripheral blood lymphocytes was also used post autologous BMT in preliminary studies. IL-2 was administered with or without peripheral blood lymphocytes, for prevention of relapse post T-cell-depleted allogeneic BMT in CML, ALL and AML, with encouraging results. The same strategy was shown to be effective in the reinduction of remission in patients with CML, who relapsed post BMT.

Cytokines in the pathophysiology and treatment of chronic B-cell malignancies. A review

Chronic B-cell malignancies are characterized by accumulation of transformed B cells of low proliferative index in lymphatic and extralymphatic tissues. Cytokines do not appear to play a role in the primary step of transformation. However, proliferation as well as inhibition of apoptosis of malignant B cells can readily be explained by cytokine effects. Clinical trials of interferons (IFN) and interleukin-2 alone or in combination have been performed in patients with hairy cell leukemia (HCL), CLL, and low- and intermediate-grade non-Hodgkin's lymphoma. While IFN alpha became standard therapy of HCL, responses in other entities were variable, ranging from 0 to 70% in selected populations. Combination of IFN and cytotoxic chemotherapy in general revealed no additional benefit as compared to chemotherapy alone. Perspectives for future clinical testing of cytokines in low-grade B-cell lymphomas are discussed.

Treatment of low-grade non-Hodgkin's lymphoma with continuous infusion of low-dose recombinant interleukin-2 in combination with the B-cell-specific monoclonal antibody CLB-CD19

Seven patients with low-grade non-Hodgkin's lymphoma were treated with a combination of a murine monoclonal antibody directed against the B-cell-specific antigen CD19 (CLB-CD19), given twice weekly, and continuous infusion of low-dose recombinant interleukin-2 (rIL-2). We demonstrated stable serum CLB-CD19 levels throughout the 12 weeks of treatment, and homing of the antibody into the tumour sites. A variable degree of antigenic modulation was noted. Prolonged treatment resulted in a sustained increase in the number of natural killer cells in the circulation with enhanced cytotoxic capacity, including antibody-dependent cellular cytotoxicity. During the first weeks of treatment, T cell activation occurred in the majority of patients. Toxicity was related to the rIL-2 treatment and consisted of transient constitutional symptoms and a flu-like syndrome without organ dysfunction. A partial remission occurred in one patient, and in another patient who was primarily leukaemic a greater than 50% reduction of circulating B cells was noted. An antitumour effect occurred early during treatment and could not be related to rIL-2-induced modulation of natural killer cell or T lymphocyte activation.

The clinical experience with interleukin-2 in cancer therapy

In May 1992, interleukin-2 (IL-2) was formally approved by the U.S. Food and Drug Administration for use in cancer treatment based on its activity in metastatic renal cell carcinoma. IL-2 alone or in combination with activated lymphocytes or other cytokines has significant anti-tumor activity against renal cell carcinoma and melanoma with response rates of 15-20%, some of which are quite durable. Limited anti-tumor effects have been noted in some patients with colorectal cancer and lymphoma. Too few patients have been studied to establish the level of activity in most other specific tumor types. The mechanism of this anti-tumor effect appears to be entirely mediated by the immunostimulatory effects of IL-2. Toxicities are dose related, but are substantial and similar regardless of the schedule of administration. Randomized trials have failed to establish (1) the superiority of high-dose bolus over continuous infusion IL-2, (2) the superiority of IL-2 plus interferon over IL-2 alone, or (3) the superiority of IL-2 plus LAK cells versus IL-2 alone. Further investigation is needed to determine the optimum dose and schedule from the standpoint of cost:benefit and risk:benefit, and to determine the role of IL-2 in the therapy of other malignant diseases.