Addition of interleukin-2 in vitro augments detection of lymphokine-activated killer activity generated in vivo

NK-mediated antibody-dependent cell-mediated cytotoxicity in solid tumors: biological evidence and clinical perspectives

The process of antibody-dependent cell-mediated cytotoxicity (ADCC) makes use of the innate immune cells providing antitumor cytotoxicity activated by antibodies linked to target cells. Natural killer (NK) cells are a small set of lymphocytes, but are considered the most important cells among those able to induce ADCC. They provoke innate immune responses and harmonise spontaneous cytotoxicity towards tumor and virus-infected cells. They are able to swiftly produce biochemical signals and cytokines so as to stimulate subsequent adaptive immune responses. Immunotherapeutics that target NK cells, augmenting their immune response, can cause the antitumor dynamics of the antibodies to be improved. The recent developments in the field of NK cell immunotherapy and genotypic factors which might affect patient responses to antibody-dependent immunotherapies are the main subject of this review, with a particular focus on the manipulations and strategies used to augment ADCC. In the next years combined treatment with monoclonal antibodies (mAbs) and immunomodulatory drugs will be an important part in antitumor therapy. The main challenge remains the difficulty in distinguishing in the clinical setting, between the target effect that many mAbs exert against specific cell membrane receptors and the ADCC effect that they too also can induce. Drugs able to activate NK cells, that are major actors in mAb-mediated ADCC, will improve the ADCC effect against tumors.

Clinical cancer therapy by NK cells via antibody-dependent cell-mediated cytotoxicity

Natural killer (NK) cells are powerful effector cells that can be directed to eliminate tumor cells through tumor-targeted monoclonal antibodies (mAbs). Some tumor-targeted mAbs have been successfully applied in the clinic and are included in the standard of care for certain malignancies. Strategies to augment the antitumor response by NK cells have led to an increased understanding of how to improve their effector responses. Next-generation reagents, such as molecularly modified mAbs and mAb-cytokine fusion proteins (immunocytokines, ICs) designed to augment NK-mediated killing, are showing promise in preclinical and some clinical settings. Continued research into the antitumor effects induced by NK cells and tumor-targeted mAbs suggests that additional intrinsic and extrinsic factors may influence the antitumor response. Therefore more research is needed that focuses on evaluating which NK cell and tumor criteria are best predictive of a clinical response and which combination immunotherapy regimens to pursue for distinct clinical settings.

Genotypes of NK cell KIR receptors, their ligands, and Fcγ receptors in the response of neuroblastoma patients to Hu14.18-IL2 immunotherapy

Response to immunocytokine (IC) therapy is dependent on natural killer cells in murine neuroblastoma (NBL) models. Furthermore, killer immunoglobulin-like receptor (KIR)/KIR-ligand mismatch is associated with improved outcome to autologous stem cell transplant for NBL. Additionally, clinical antitumor response to monoclonal antibodies has been associated with specific polymorphic-FcγR alleles. Relapsed/refractory NBL patients received the hu14.18-IL2 IC (humanized anti-GD2 monoclonal antibody linked to human IL2) in a Children's Oncology Group phase II trial. In this report, these patients were genotyped for KIR, HLA, and FcR alleles to determine whether KIR receptor-ligand mismatch or specific FcγR alleles were associated with antitumor response. DNA samples were available for 38 of 39 patients enrolled: 24 were found to have autologous KIR/KIR-ligand mismatch; 14 were matched. Of the 24 mismatched patients, 7 experienced either complete response or improvement of their disease after IC therapy. There was no response or comparable improvement of disease in patients who were matched. Thus KIR/KIR-ligand mismatch was associated with response/improvement to IC (P = 0.03). There was a trend toward patients with the FcγR2A 131-H/H genotype showing a higher response rate than other FcγR2A genotypes (P = 0.06). These analyses indicate that response or improvement of relapsed/refractory NBL patients after IC treatment is associated with autologous KIR/KIR-ligand mismatch, consistent with a role for natural killer cells in this clinical response.

Nursing Care of Patients Receiving High-Dose, Continuous-Infusion Interleukin-2 With Pulse Dose and Famotidine

High-dose, continuous-infusion interleukin-2 (IL-2) followed by pulse dose and concurrent administration of famotidine has demonstrated response rates of 64% and 33% in patients with metastatic melanoma and metastatic renal cell carcinoma, respectively. Currently, no information is available concerning the nursing care of patients receiving that IL-2 regimen. Given the high response rates of patients on the treatment, attention by the nursing profession is warranted. Effective nursing care of patients receiving IL-2 is essential to the regimen's success. Recognition and prompt treatment of common side effects lead to better patient outcomes. This article provides nurses with an overview of the treatment regimen, expected side effects, psycho-social considerations, and discharge instructions for patients receiving continuous-infusion plus pulse IL-2 and famotidine.

Continuous infusion interleukin-2 and intravenous famotidine in metastatic melanoma

Lymphokine-activated killer cell (LAK) cytotoxicity against tumor cells is induced by the use of high-dose infusional interleukin-2 (IL-2). LAK cytotoxicity against neoplastic cells may be augmented by famotidine. Twelve (12) patients have been treated with continuous infusion IL-2 (18 MIU/m2/24 hours) for 72 hours and famotidine 20 mg IVPB twice per day. Cycles were repeated every 3 weeks. These patients were of median age--67 years (range, 25-79), had a median performance status of 1 (range, 0-1), and had metastatic sites, including lung, lymph node, subcutaneous/soft tissue, and liver. The most common toxicities of this regimen were fever, rigors, nausea/emesis, hypophosphatemia, and hypomagnesemia. Three (3) partial responses have been seen (25% response rate). One (1) of these responders has undergone complete surgical resection and is disease-free at 15+ months. Four (4) patients are alive at a median of > 25 months. The median survival for all patients is 13 months. This combination of infusional IL-2 with famotidine is active in metastatic melanoma.

Activity of Continuous Infusion Plus Pulse Interleukin-2 with Famotidine in Patients with Metastatic Kidney Cancer or Melanoma Previously Treated with Interleukin-2

Lymphokine-activated killer (LAK) cells generated by high-dose continuous infusion interleukin-2 (IL-2) are able to nonspecifically lyse melanoma and kidney cancer cells. In vitro famotidine enhances cytotoxicity of LAK against tumor cells, possibly by increasing IL-2 uptake at the IL-2 receptor on lymphocytes. Outpatient IL-2 regimens typically have response rates of 15% or less, with most patients eventually experiencing progressive disease. Second-line therapy is, therefore, needed. We treated 11 patients (6 with metastatic melanoma; 5 having metastatic kidney cancer) who had previously experienced progressive disease on prior IL-2 regimens, with a combination of famotidine 20 mg intravenously (i.v.) twice per day and continuous-infusion IL-2 18 MIU/M2/24 hours x 72 hours, followed 24 hours later by a pulse IL-2 dose (18 MIU/M2 over 15 minutes). Cycles were repeated every 3 weeks. Patient characteristics were: 9 males, median age 63 years (range, 57-75), median Eastern Cooperative Oncology Group (ECOG) performance status: 1; most common metastatic sites: lungs, lymph nodes, and soft tissue/subcutaneous (s.c.); median number of cycles received: 4; most common toxicities were fever, nausea/emesis, hypophosphatemia, and hypomagnesemia. Five (5) patients (3 with melanoma, 2 with kidney cancer) have had partial responses. Two (2) patients with kidney cancer have been converted to complete responders with resection of residual disease, remaining without relapse at 5+ and 20+ months. Responding sites are lungs, lymph nodes, abdominal mass, and s.c. Median duration of response was 9.5 months. Median survival was 12 months. This combination has activity in patients with metastatic kidney cancer or melanoma who have received prior IL-2.

Continuous Infusion Interleukin-2 and Antihistamines in Metastatic Kidney Cancer

A prior randomized trial suggested a possible survival advantage favoring the combination of histamine and subcutaneous interleukin-2 (IL-2), compared to IL-2 alone in patients with metastatic melanoma. It has been postulated previously that antihistamines may, therefore, actually be antagonistic to IL-2 and thus interfere with its antitumor activity. We have previously shown no such antagonistic effect in patients with melanoma receiving IL-2 and antihistamines when reviewing the known literature. We sought to determine whether there was any negative effect of the combination in patients with metastatic kidney cancer. A PubMed literature search between 1985 and 2005 was done. High-dose continuous (or constant) infusion (CIV) interleukin-2 was used as the reference therapy because of the relatively constant IL-2 levels generated by this approach. Studies in which cimetidine, ranitidine, or famotidine were regularly scheduled and administered concurrently with IL-2 were included. Thirteen studies were identified. A total of 47 patients responded to therapy. Total response rate = 22%; 95%; Confidence Interval: 17%-28%. Eleven complete responses were noted. Complete response rate = 5%; 95% Confidence Interval: 3%-9%. These response rates are consistent with previously noted IL-2 response rates. In this study of CIV IL-2 and antihistamines, this combination appears to be active in metastatic kidney cancer. There appears to be no negative effect of antihistamine on the CIV IL-2 response rate in this disease.

High-Dose Continuous Infusion Plus Pulse Interleukin-2 and Famotidine in Metastatic Kidney Cancer

High-dose continuous infusion interleukin-2 (IL-2) regimens generate a higher degree of lymphokine activated killer cell (LAK) cytotoxicity when tested against tumor cells in vitro and a higher rebound lymphocytosis in vivo than do bolus IL-2 regimens. Lymphocytes initially activated by continuous infusion IL-2 have increased cytotoxicity against cancer cells when they are subsequently pulsed with additional IL-2. Famotidine may enhance LAK cytolytic ability. Six patients with kidney cancer have been treated with a combination of famotidine 20 mg intravenous bid and continuous infusion IL-2 (18 MIU/sq m/24 hours) for 72 hours, followed by a 24-hour rest, then IL-2 18 MIU/sq m over 15-30 minutes. The most common metastatic sites were the lung, lymph node, and bone. Median number of cycles received = 5 (range, 3-8). The most common toxicities were fever, rigors, nausea/emesis, hypophosphatemia, hypotension, elevated creatinine, and metabolic acidosis. There were no treatment-related deaths, and no patients required intensive care admission. Two partial responses (33% response rate) have been seen. Median survival has not been reached at greater than 8 months. The combination of high-dose continuous infusion plus pulse IL-2 and famotidine is active in metastatic kidney cancer. An accrual of additional patients is needed to better assess the response rate.

High-Dose Continuous Infusion Plus Pulse Interleukin-2 and Famotidine in Melanoma

High-dose, continuous infusion interleukin-2 (IL-2) regimens generate greater Lymphokine Activated Killer cell (LAK) cytotoxicity in vitro and a higher rebound lymphocytosis in vivo than do bolus IL-2 regimens. Lymphocytes initially activated by continuous infusion IL-2 then subsequently pulsed with IL-2 have increased cytotoxicity against cancer cells. Famotidine may enhance the lysis of tumors by cytotoxic lymphocytes. Fourteen patients with melanoma were treated with famotidine 20 mg intravenously twice per day and continuous infusion IL-2 (18 MIU/sq m/24 hours) for 72 hours, followed by a 24-hour rest, then IL-2 18 MIU/sq m over 15-30 minutes for 1 dose (12 patients) or daily for 3 doses (2 patients). Most common toxicities were fever, nausea/emesis, hypophosphatemia, hypomagnesemia, and rigors. Nine partial responses (64% response rate; 95% Confidence Interval: 39%-84%) have been seen. Median survival has not been reached at greater than 10 months. Two patients responding to therapy showed an increase in detectable CD 56(+) cells in serial subcutaneous or lymph node biopsies, while 1 patient undergoing progression of disease had no such infiltrate. High-dose, 72-hour continuous infusion plus pulse interleukin-2 with famotidine has activity in melanoma. CD 56(+) cells may play a role in responding patients.

Phase I clinical trial of the immunocytokine EMD 273063 in melanoma patients

PURPOSE

To evaluate the safety, toxicity, in vivo immunologic activation, and maximum-tolerated dose (MTD) of EMD 273063 (hu14.18-IL-2) in patients with metastatic melanoma.

PATIENTS AND METHODS

Thirty-three patients were treated with EMD 273063, a humanized anti-GD2 monoclonal antibody (mAb) linked to interleukin-2 (IL-2). EMD 273063 was given as a 4-hour intravenous infusion on days 1, 2, and 3 of week 1. Patients with stabilization or regression of disease could receive a second course of treatment at week 5. Dose levels evaluated were 0.8, 1.6, 3.2, 4.8, 6.0, and 7.5 mg/m2/d.

RESULTS

Nineteen of 33 patients completed course 1 with stable disease and went on to receive course 2. Eight patients had stable disease on completion of course 2. Grade 3 adverse events included hypophosphatemia (11 patients), hyperglycemia (three patients), hypotension (two patients), thrombocytopenia (one patient), hypoxia (three patients), elevated hepatic transaminases (two patients), and hyperbilirubinemia (one patient). Opioids were required for treatment-associated arthralgias and/or myalgias during 17 of 52 treatment courses. No grade 4 adverse events were observed. Dose-limiting toxicities at the MTD included hypoxia, hypotension, and elevations in AST/ALT. Grade 3 toxicities were anticipated based on prior studies of IL-2 or anti-GD2 mAbs, and all resolved. Immune activation was induced, as measured by lymphocytosis, increased peripheral-blood natural killer activity, and cell numbers, and increased serum levels of the soluble alpha chain of the IL-2 receptor complex.

CONCLUSION

Treatment with the immunocytokine EMD 273063 induced immune activation and was associated with reversible clinical toxicities at the MTD of 7.5 mg/m2/d in melanoma patients.

Generation and characterization of a single-gene encoded single-chain immunoglobulin-interleukin-2 fusion protein

BACKGROUND

Interleukin-2 (IL-2), a potent inducer of cellular immune responses, has been used for biological therapy of human cancer; however, the high doses of IL-2 required to mediate patients' immune responses can cause considerable systemic toxicity. The murine monoclonal antibody (MAb) CC49, which reacts with tumor-associated glycoprotein (TAG)-72, expressed on a variety of human carcinomas, has shown excellent tumor localization in recent clinical trials.

OBJECTIVES

Development and characterization of a single-chain immunoglobulin-IL-2 (SCIg-IL-2) fusion protein which, by delivering IL-2 selectively to the tumor site, can serve as an effective reagent for CC49/IL-2 combination therapy.

STUDY DESIGN

A single-gene encoding the SCIg-IL-2 fusion protein derived from the chimeric (c) CC49 was designed, generated and inserted in an expression vector. The monomeric single-chain protein consisted of the CC49 heavy and light chain variable domains covalently jointed through a (GGGGS)3 linker peptide. The carboxyl end of the variable domain of the light chain was linked to the amino terminus of the human gamma 1 Fc through the hinge region, and the carboxyl end of the CH3 domain was linked to the amino terminus of the human IL-2 through a GGGSGGG linker peptide. The SCIg-IL-2, expressed from the murine myeloma cells transfected with the expression construct, was characterized for its antigen-binding specificity, antibody effector functions and IL-2 biological activity.

RESULTS AND CONCLUSION

Transfection of murine myeloma cells with the single-gene expression construct SCIg-IL-2 expressed a single-chain protein of approximately 70 kD, which was secreted into tissue culture fluid as a homodimer of approximately 140 kD. SCIg-IL-2 competed completely with cCC49 for binding to the TAG-72 antigen, but approximately three- to four-fold more of the SCIg-IL-2 was required to achieve levels of competition similar to those observed with the murine or chimeric CC49. With human effector cells, the fusion protein mediated lysis of TAG-72-positive human carcinoma cells. Prior treatment of human effector cells with 100 U/ml of human IL-2 enhanced the fusion protein-mediated cytolysis from 32 to 65%. At doses of > or = 1 ng/ml, the stimulatory effect of SCIg-IL-2 on IL-2 dependent murine HT-2 cell proliferation was comparable to that of the recombinant human IL-2. The single-gene construct may also facilitate inoculation of the gene in animal tissue for in vivo expression of the fusion protein.

A recombinant antibody-interleukin 2 fusion protein suppresses growth of hepatic human neuroblastoma metastases in severe combined immunodeficiency mice

A genetically engineered fusion protein consisting of a human/mouse chimeric anti-ganglioside GD2 antibody (ch14.18) and recombinant human interleukin 2 (rhIL-2) was tested for its ability to target rhIL-2 to tumor sites and stimulate immune effector cells sufficiently to achieve effective tumor cell lysis in vivo. The ch14.18-IL-2 fusion protein proved more effective than equivalent doses of rhIL-2 in suppressing dissemination and growth of human neuroblastoma in an experimental hepatic metastases model of scid (severe combined immunodeficiency) mice reconstituted with human lymphokine-activated killer cells. The ch14.18-IL-2 fusion protein was also more proficient than equivalent doses of rhIL-2 in prolonging the life-span of these animals. This recombinant antibody-cytokine fusion protein may prove useful for future treatment of GD2-expressing human tumors in an adjuvant setting.

Clinical and immunological effects of human recombinant interleukin-2 given by repetitive weekly infusion to normal dogs

Four normal adult dogs received two consecutive weekly cycles of human recombinant interleukin-2 (IL-2) by continuous infusion for 4 days/week. The dose of IL-2 given to each dog was 3 x 10(6) units m-2 day-1. Toxicities consisted of mild vomiting, diarrhea, and lethargy to varying degrees in all the dogs. These side-effects were reversed when the treatment was discontinued. Fever, tachypnea, and weight gain were not seen. A marked lymphocytosis and eosinophilia developed in all dogs after completion of each course of IL-2 (resulting in a more than sevenfold increase in each cell type) and persisted for more than 1 month in some. Fresh peripheral blood lymphocytes (PBL) obtained during this lymphocytosis mediated enhanced in vitro lysis of a natural-killer-cell-sensitive canine tumor cell line (CTAC). The in vitro proliferative responses of these same PBL to IL-2 could be detected earlier, progressed faster, and involved more cells than PBL tested prior to IL-2 infusion. Thus, a relatively well-tolerated regime of IL-2 in dogs can induce dramatic increases in lymphocyte numbers and activation, which is associated with augmentation of their in vitro antitumor reactivity. The clinical effectiveness of this immunotherapeutic approach remains to be tested in tumor-bearing dogs where it could serve as a relevant large-animal model for immunotherapy of cancer with IL-2.

Induction of lymphokine-activated killer (LAK) activity in canine lymphocytes with low dose human recombinant interleukin-2 in vitro

Interleukin-2 (IL-2) is an immunostimulatory cytokine that induces activation of peripheral blood lymphocytes (PBL) which can mediate augmented tumor cytotoxicity. Several regimens using IL-2 as treatment for metastatic melanoma and renal carcinoma have shown measurable tumor responses in 10-20% of human patients. Our overall goals are to determine the efficacy of IL-2 as an adjuvant treatment for canine tumors. In order to evaluate the possibility to extend the use of IL-2 in vivo in the dog, we examined the ability of a clinically relevant (low) dose of human recombinant IL-2 (100 units/ml) to enhance the tumoricidal properties of canine PBL in vitro. This was particularly important considering the need to establish the effects on canine PBL by IL-2 at a dose that is potentially achievable in vivo with acceptable side effects. Our data show, for the first time, the ability to separate canine natural killer (NK) cell activity from lymphokine-activated killer (LAK) cell activity (induced with a low IL-2 dose) mediated by canine PBL against two canine cell lines (CTAC and CML-10) used as targets in 4 vs. 16 hour killing assays. LAK cells generated by stimulation of canine PBL with 100 units/ml of IL-2 for 72 hours, could kill CTAC or CML-10 targets up to 11 or 18 times more efficiently, respectively, than fresh PBL in a 4 hour assay. However, the killing of efficiency of the LAK cells was only 2- to 3-fold greater than that of the fresh PBL in a 16 hour assay. This apparent reduction in the killing efficiency of the LAK cells was mostly due to increased spontaneous NK activity by the fresh PBL after 16 hours in culture; both the LAK cells and the fresh PBL (NK cells) mediated a greater overall cytotoxicity after 16 hours than they did in the 4 hour assays. These results indicate that a low dose of human recombinant IL-2 can augment tumor killing by canine PBL in vitro, and suggest that it may be feasible to examine the potential use of IL-2 as an immunotherapeutic agent in tumor-bearing dogs.

Short-duration in vitro interleukin-2-activated mononuclear cells for advanced cancer. A Hong Kong biotherapy pilot study trial

BACKGROUND

In vitro studies have demonstrated that a brief exposure of peripherally collected mononuclear cells to high-dose human recombinant interleukin-2(rIL-2) will generate a population of pulsed lymphokine-activated killer (LAK) cells. These cells have similar cytotoxicity against natural killer cells and resistant and sensitive target cells as compared with the standard LAK cells incubated for 3-7 days with rIL-2. Therefore, the authors conducted a pilot study to investigate the activity of pulsed LAK cells in patients with advanced cancer.

METHODS

Nineteen patients were enrolled in a pilot study, and pulsed LAK cell treatment was administered two times per week for 4 weeks, followed by similar cycles if patients remained free of disease progression and unacceptable toxic effects.

RESULTS

Toxic effects consisted mainly of fever, chills, nausea, and dizziness but were self-limiting and mild. Most cycles were administered on an outpatient basis. There were six partial responses (31%), occurring in two of three patients with renal cell carcinoma, two of four with hepatocellular carcinoma, one of seven with non-small cell lung carcinoma, and one of one with ovarian carcinoma. Two minimal responses were seen in one case each of melanoma and carcinoma of colon. Nine other patients had disease stabilization for 16 weeks, and two additional patients had disease progression. Phenotyping of peripheral mononuclear cells showed increases in CD56 and CD25 populations with no in vivo rIL-2 being administered after treatment with pulsed LAK cells.

CONCLUSIONS

The relative ease in generating pulsed LAK cells and the associated mild toxic effects enable prolonged stimulation of the effector cells of the patients against sensitive tumor targets, with a response rate comparable to those of high-dose rIL-2 and LAK cell treatment. Therefore, it may be a theoretically ideal adjuvant for patients with renal cell carcinoma, melanoma, and hepatoma and other applicable patients after bone marrow transplantation. The initial high response rate in patients with late-stage renal cell carcinoma and hepatocellular carcinoma indicates the need for additional confirmation.

Malignant melanoma and renal cell carcinoma: immunological and haematological effects of recombinant human interleukin-2

The immunological and haematological effects of continuous infusion of recombinant human interleukin-2 (rhIL-2) in 6 patients with metastatic melanoma and 6 with disseminated renal cell carcinoma are reported. In patients with malignant melanoma dacarbazine was given before IL-2; in renal cell carcinoma IL-2 alone was given. In malignant melanoma, 1 complete (CR) and 1 partial response (PR) were seen; 2 patients had stable disease (SD) and 2 progressive disease (PD). In renal cell carcinoma 4 patients had SD and 2 PD. Toxicity of IL-2 therapy was minimal. All patients showed increased cytotoxicity, that was not major histocompatibility complex restricted, towards target cells sensitive and insensitive to natural killer cells. These activities varied between individual patients and were less marked in cases of renal cell carcinoma. Cellular proliferative responses increased in all patients, being consistently higher following the first course of therapy, as did HLA-DR, CD16 and CD25 activation marker expression. Hypersegmentation of neutrophils and eosinophilia were commonly observed, and in renal cell carcinoma these changes were accompanied by abnormal lymphocyte morphology.

Interleukin-2 dose, blood monocyte and CD25+ lymphocyte counts as predictors of clinical response to interleukin-2 therapy in patients with renal cell carcinoma

The purpose of this study was to determine immunological parameters in the peripheral blood that correlate with the clinical effect of interleukin-2 (IL-2) in patients with metastatic renal cell cancer. A group of 26 patients with metastatic renal cell cancer underwent IL-2 treatment using a 36-day schedule with continuous intravenous IL-2 infusion (3 x 10(6) units m-2 day-1) administered from days 1 to 5 and days 12 to 16. The white blood cell count and the absolute and relative number of neutrophils, lymphocytes, eosinophils and monocytes were recorded six times in peripheral blood during the treatment. Also the blood counts of T cell and NK cell subsets and cells expressing the T cell activation markers IL-2R alpha and VLA-1 were measured. The lymphokine-activated killer (LAK) cell cytotoxicity was measured either with or without additional in vitro stimulation by IL-2. Multivariate statistical analysis showed that the clinical responses were related to the administered dose of IL-2, to a low number of blood cells expressing IL-2 receptors and to a reduction in the blood monocyte count (P less than 0.05).