Effect of continuous complement inhibition using soluble complement receptor type 1 on survival of pig-to-primate cardiac xenografts.

A single bolus of soluble complement (C) receptor type 1 (sCR1, TP-10) has been shown to delay hyperacute rejection (HAR) of porcine cardiac xenografts (Xgs) by primate recipients. In these recipients, C activity slowly returned and C deposition was noted in the Xgs at rejection. To evaluate the effect of sustained C inhibition using sCR1 on HAR, two additional cynomolgus monkeys received porcine cardiac Xgs and a continuous infusion of sCR1. In the first recipient, Xgs survival was 5 days (120+ hr), whereas in the second, Xg survival was 7 days (168+ hr). Serial biopsies of the Xgs were remarkable for an increasing cellular infiltrate composed predominantly of neutrophils and macrophages, and the development of edema, hemorrhage, and myocyte necrosis. These findings suggest that once C-mediated HAR has been inhibited, infiltration of the Xg by these cells may lead to accelerated acute rejection, which is an additional barrier to successful longer term Xg survival.

The effects of soluble recombinant complement receptor 1 on complement-mediated experimental glomerulonephritis.

Complement is a major mediator of tissue injury in several types of glomerulonephritis. However, no therapeutic agents that inhibit complement activation are available for human use. sCR1 (TP10, BRL 55736) is a recombinant, soluble human complement receptor 1 (CR1) molecule lacking transmembrane and cytoplasmic domains that inhibits C3 and C5 convertase activity by preferentially binding C4b and C3b. To test the efficacy of sCR1 on complement-mediated glomerulonephritis, rats were pretreated with sCR1 (60 mg/kg per day) before and during the induction of three models of complement-dependent glomerulonephritis (concanavalin A and antithymocyte serum models of proliferative glomerulonephritis, passive Heyman nephritis). Daily sCR1 and complement hemolytic activity levels were measured, and renal histology and urine protein excretion were examined. Mean serum sCR1 levels of 100 to 200 micrograms/mL were maintained with a reduction in complement hemolytic activity to less than 15% in most animals. In the antithymocyte serum model, sCR1-treated animals had significant reductions in mesangiolysis, glomerular platelet and macrophage infiltrates, and proteinuria at 48 h. In the concanavalin A model, sCR1 significantly reduced glomerular C3 and fibrin deposits, platelet infiltrates, and proteinuria at 48 h. In passive Heymann nephritis, proteinuria was also significantly reduced (199 +/- 8.5 versus 125 +/- 16 mg/day, P < 0.002) at 5 days. It was concluded that sCR1 significantly reduces both morphologic and functional consequences of several different types of complement-mediated glomerulonephritis and deserves evaluation as a potential therapeutic agent in complement-mediated immune glomerular disease in humans.

The effect of soluble complement receptor type 1 on hyperacute rejection of porcine xenografts.

The use of xenografts (Xgs) from distantly related species to relieve the increasing shortage of organs for clinical transplantation is prevented by the occurrence of hyperacute rejection (HAR). This process, in which C activation plays a central role, cannot be inhibited with currently available immunosuppressants. In two clinically relevant xenotransplantation models, this study evaluated the effect of C inhibition using recombinant soluble complement receptor type 1 (sCR1) on HAR. In an ex vivo model in which porcine cardiac Xgs were perfused with human blood, cardiac function ceased within 34 min when the perfusate blood was untreated (n = 3). When the perfusate blood was treated with sCR1 (300 micrograms/ml), cardiac Xg function was maintained for up to 4 hr (n = 3). Immunohistologic examination of these Xgs demonstrated deposition of C3b/iC3b and C3d in Xgs perfused with untreated human blood but only C3d deposition in those Xgs perfused with sCR1-treated human blood. These findings are consistent with the cofactor activity of sCR1 for factor I-mediated degradation of deposited C3b/iC3b to C3d. Treatment with sCR1 also prevented the histopathologic changes of HAR observed when untreated blood was used as the perfusate. In an in vivo pig-to-primate heterotopic cardiac xenotransplantation model, in which porcine Xgs transplanted into untreated cynomolgus monkey recipients underwent HAR in 1 hr or less (n = 3), a single intravenous bolus of sCR1 (15 mg/kg) administered to the recipient immediately before Xg reperfusion markedly inhibited total and alternative pathway serum C activity and prolonged Xg survival to between 48 and 90 hr (n = 5). These studies confirm the important role of C activation in HAR of porcine cardiac Xgs by primates and indicate that sCR1 may be a useful agent for xenotransplantation.

A phase II study of dacarbazine and cisplatin in combination with outpatient administered interleukin-2 in metastatic malignant melanoma.

BACKGROUND: Based on prior experience with dacarbazine (DTIC) and an outpatient interleukin-2 (IL-2) regimen, the current study was conducted to improve the antitumor efficacy and assess the immunologic interactions between chemotherapy and IL-2. METHODS: Thirty-two patients were registered onto a treatment program, which included DTIC 750 mg/m2 with cisplatin 100 mg/m2, each by intravenous bolus on day 1. Recombinant IL-2 was administered on an outpatient basis intravenously by 15-30-minute infusion (24.0 x 10(6) IU/m2) daily on days 12-16 and 19-23 of a 28-day cycle for three cycles and then every 42 days for responding patients. RESULTS: There were responses in 13 of the 32 registered patients (41% response rate), including five complete and eight partial remissions. Responses in the liver, lung, spleen, lymph nodes, and soft tissue sites were noted. The median duration of response was 8.0 months (range, 3.0-20.0+ months), and the overall median survival duration was 10.2 months. Three patients (9%) are alive, free of disease, without any treatment at 32.0+, 36.0+, and 42.0+ months after initiation of treatment. Only minor nephrotoxicity was observed, and treatment delays were rare. CONCLUSIONS: Additional chemotherapeutic, hormonal, or biologic agents may be added to enhance efficacy further if they have toxicities that do not overlap.

Complement inhibition with soluble complement receptor type 1 in cardiopulmonary bypass.

Although complement activation during cardiopulmonary bypass (CPB) is well documented, its pathogenic role in postperfusion organ injury is unproven. In this study, soluble human complement receptor type 1 (sCR1), a potent inhibitor of complement activation, was used to determine the contribution of complement activation to pulmonary injury in a porcine model of CPB. In vitro experiments demonstrated that sCR1 inhibits both classic and alternative complement pathways in the pig. Seven control piglets and 6 piglets treated with sCR1 (12 mg/kg intravenously) underwent 2 hours of hypothermic (28 degrees C) CPB followed by 2 hours of observation. In control piglets, total hemolytic complement activity and functional activities of C3 and C5 declined to 61.3%, 67.8%, and 61.4% of prebypass values, respectively, after 2 hours of CPB. Plasma from animals treated with sCR1 had virtually no hemolytic activity (total hemolytic complement activity < 5% of baseline), demonstrating effective complement inhibition. Similar degrees of neutropenia developed in the two groups during CPB, and there was no difference in post-CPB lung tissue myeloperoxidase level. Two hours after CPB, pulmonary vascular resistance increased 338% in control piglets but only 147% in piglets pretreated with sCR1 (p < 0.05); the alveolar-arterial gradient was not significantly different between controls (331 +/- 52 mm Hg) and piglets receiving sCR1 (290 +/- 85 mm Hg). Histologic examination revealed similar degrees of pulmonary edema in both groups. These data constitute direct evidence that complement activation plays a pathogenic role in lung injury after CPB.(ABSTRACT TRUNCATED AT 250 WORDS)

Lung injury after deposition of IgA immune complexes. Requirements for CD18 and L-arginine.

Acute lung injury produced by deposition of IgA immune complexes is complement-dependent, neutrophil-independent, oxygen radical-mediated, and may be a result of the formation of the hydroxyl radical (HO) generated directly or indirectly from activated lung macrophages. The current studies were designed to evaluate further the pathophysiologic events that occur after intrapulmonary deposition of IgA immune complexes. Pretreatment of rats with the human recombinant soluble complement receptor-1 resulted in marked attenuation of IgA immune complex-induced lung injury. Intravenous administration of antibody to CD18, but not antibody to CD11b, was highly protective against lung injury. Treatment of animals with either anti-endothelial leukocyte-adhesion molecule-1 or anti-TNF-alpha, both of which were highly protective against IgG immune complex-induced lung injury, had no protective effects in the model of IgA immune complex-induced lung injury. Immunohistochemical analysis revealed up-regulation of the endothelial leukocyte adhesion molecule-1 in the pulmonary vasculature after deposition of IgA immune complexes. This up-regulation was TNF-alpha-dependent. The arginine analog, NG-monomethyl-L-arginine, was highly protective against IgA immune complex-induced lung injury. This protective effect was reversed by the co-presence of L-arginine (but not D-arginine). Protective interventions against IgA immune complex-induced lung injury were inversely correlated with the numbers of macrophages that could be retrieved by lung lavage. These data suggest fundamental differences in the pathogenesis of lung injury after intrapulmonary deposition of IgA immune complexes, as compared with injury caused by deposition of IgG immune complexes. In the latter, neutrophils, intrapulmonary generation of TNF-alpha, and up-regulation of pulmonary vascular endothelial leukocyte-adhesion molecule-1 are required for the full development of lung injury, whereas no such requirements appear in the case of IgA immune complex-induced lung injury. Full expression of IgA immune complex-induced lung injury also appears to require L-arginine, suggesting a possible role for nitric oxide or its derivatives in events ultimately leading to injury.

Protective effects of soluble CR1 in complement- and neutrophil-mediated tissue injury.

Complement activation is an important step for triggering of acute inflammatory reactions. Soluble human recombinant complement receptor type 1 (sCR1) blocks complement activation by both classical and alternative pathways. In addition to glycogen-induced peritonitis, three models of complement-dependent acute inflammatory injury have been used to assess the protective effects of sCR1: lung and dermal injury after intraalveolar or intradermal deposition of IgG immune complexes; acute lung injury resulting from intravascular activation of complement after the i.v. injection of cobra venom factor; and acute skin and lung injury (at 4 h) after thermal trauma involving 25 to 30% total body surface area. Vascular injury was quantified by increases in vascular permeability, hemorrhage, neutrophil infiltration, and, as indicated, tissue water content. Intravenous infusion of sCR1 reduced lung and dermal vascular injury in all models studied. In glycogen-induced peritoneal exudates sCR1-reduced neutrophil accumulation by 79%. In animals undergoing IgG immune complex-induced alveolitis, sCR1 treatment reduced vascular permeability and hemorrhage by 72 and 71%, respectively, and tissue accumulation of neutrophils was reduced by 68%. After cobra venom factor injection, sCR1 reduced increases in lung vascular permeability by 67%, hemorrhage by 73%, and lung myeloperoxidase content by 55%. Four hours after thermal injury of skin, sCR1-treated animals demonstrated significant protection against lung injury; increases in vascular permeability and hemorrhage were reduced by 45 and 46%, respectively, and myeloperoxidase content was lowered by 39%. In thermal injury of the skin, sCR1 injection reduced dermal vascular permeability by 25% at 1 h (p = NS) and 44% at 4 h. Water content in skin biopsies was also decreased. There was a dose-response relationship between the amount of sCR1 infused and the extent of protection in each of the injury models. These data demonstrate that sCR1 offers significant protection against complement-dependent tissue injury in the animal models studied and that the protective effects are related to reduced neutrophil content.

A phase I trial of recombinant human macrophage colony-stimulating factor by rapid intravenous infusion in patients with refractory malignancy.

Twenty patients with advanced cancer for which there was no effective standard therapy or whose disease was refractory to standard therapy were treated with recombinant macrophage colony-stimulating factor (rM-CSF). The rM-CSF was administered by intravenous bolus infusion for 5 consecutive days every other week for 2 treatment weeks. The doses administered ranged from 30 to 33,000 micrograms/m2/day. There was no intrapatient dose escalation. There were minimal to no systemic side effects seen, except for acute dyspnea noted in three patients. The dyspnea was felt to be related to the rate of infusion and did not recur in one patient given additional rM-CSF at a slower infusion rate. The major hematologic effect seen was a mild decrease in platelet count, which began to recover while the patients continued to receive the rM-CSF. The clearance of rM-CSF was dose dependent. Lower doses resulted in a saturable mechanism felt to represent cellular uptake. Clearance at higher doses demonstrated both a first-order mechanism at high serum rM-CSF concentrations, representing renal clearance, as well as a saturable mechanism at low serum concentrations. The maximum mean serum half-life was reached at dose levels of greater than or equal to 3,690 micrograms/m2 and was in the range of 234-258 min. By this route of administration, rises in absolute monocyte count were slight and seen only at doses of greater than or equal to 450 micrograms/m2 during the second therapy week. The maximum tolerated dose was not reached in this study because of lack of availability of rM-CSF.

Renal cell carcinoma: treatment with recombinant interleukin-2 plus beta-interferon.

Preclinical data have demonstrated synergy between interleukin-2 (IL-2) and beta-interferon (IFN-beta) in stimulating natural-killer (NK) cell activity and in increasing expression of IL-2 receptors. Based on results of a phase I trial, a combination of IL-2 and IFN-beta was administered three times weekly by intravenous (IV) bolus injection with 5 x 10(6) Cetus U/m2 of IL-2 and 6 x 10(6) U/m2 of IFN-beta to 24 patients with advanced renal cell carcinoma (RCC). Of 22 assessable patients there were six (27%) objective responses including one complete remission (CR) and five partial responses (PRs). There were three minor responses (MRs), 11 stable disease (SD), and two progressive disease (PD). Two of the objective responses have continued for almost 2 years. Response sites include lymph nodes, lungs, and bone. Toxicities requiring dose reduction include arthralgia, weight loss, fatigue, decreased performance status, depression, and hypotension. Five of 10 patients who had a prior nephrectomy without local recurrence achieved an objective response as compared with only one of 12 without a prior nephrectomy or with a local recurrence (P = .04). Mean peak lymphokine-activated killer (LAK) cell activity of the objective responders was 88 lytic units (LU) as compared with 4 LU in the nonresponders (P = .01). Mean peak NK cell activity was 288 LU in the objective responders as compared with 100 LU in the nonresponders (P = .10).(ABSTRACT TRUNCATED AT 250 WORDS)

A phase I trial of subcutaneously administered recombination tumor necrosis factor to patients with advanced malignancy.

Nineteen patients with advanced cancer for which there was no effective standard therapy or whose disease was refractory to standard therapy were treated with recombinant tumor necrosis factor (rTNF). The rTNF was administered subcutaneously for 5 consecutive days every other week for 3 treatment weeks. The doses administered ranged from 5 micrograms/m2/day to 150 micrograms/m2/day. There was no intrapatient dose escalation. Systemic side effects of chills, fever, hypotension, nausea, vomiting, and headache were mild and self-limiting. At the maximum tolerated dose of 150 micrograms/m2/day, five of seven patients experienced moderate to severe thrombocytopenia. Mild rapid declines in total leukocyte count occurred within 60-90 min of administration of the drug, followed by a rise in the total leukocyte count by 120 min. When the total daily dose was administered in a single subcutaneous site, skin ulceration and necrosis occurred at the 100 micrograms/m2/day dose. By giving the total daily dose in two subcutaneous sites, the maximum tolerated dose increased to 150 micrograms/m2/day, and there was no further skin ulceration or necrosis. Skin necrosis occurred in the abdomen and thigh but not on the upper extremity at the 100 micrograms/m2/day dose given in a single site. There was no other significant organ toxicity. No rTNF was detectable in the serum even at the highest doses. No antibodies to TNF developed in any of the patients. The recommended dose of rTNF for Phase II trials given for 5 days subcutaneously is 150 micrograms/m2/day divided into two or more sites.

Exacerbation of epidemic Kaposi's sarcoma with a combination of interleukin-2 and beta-interferon: results of a phase 2 study.

Epidemic Kaposi's sarcoma (EKS) is the most common neoplastic manifestation of acquired immune deficiency syndrome (AIDS). The underlying immune deficiency can be partially reversed in vitro with interleukin-2 (IL-2). The type 1 interferons (IFN), alpha and beta, inhibit the growth of the etiologic agent of AIDS, the human immunodeficiency virus, have antitumor activity against Kaposi's sarcoma, and are synergistic with IL-2 in stimulating natural killer cell activity. Four patients with EKS were treated three times weekly with simultaneous intravenous injections of recombinant IL-2 (5 X 10(6) Cetus units/m2) and recombinant IFN-beta (6 X 10(6) units/m2). All patients had generalized disease, were without systemic symptoms, had no prior opportunistic infection, and had stable disease at the initiation of therapy. No patient had an objective response. Three patients exhibited rapid disease progression within 2-4 weeks of starting treatment, necessitating discontinuation of therapy and early closure of the study. This adverse result may have resulted from the significant levels of gamma-interferon (IFN-gamma) that can be generated with this dose and schedule of IL-2. Investigators using IL-2 should monitor IFN-gamma levels and avoid intermediate to high-dose bolus IL-2 therapy in patients with EKS.

Specificity of tumor necrosis factor toxicity for human mammary carcinomas relative to normal mammary epithelium and correlation with response to doxorubicin.

By using a unique short-term culture system capable of growing both normal and malignant breast epithelial tissue, human recombinant tumor necrosis factor (TNF) showed preferential cytotoxicity to malignant cells as compared to the corresponding nonmalignant cells. Most of the malignant specimens were sensitive to TNF with 13 of 18 specimens showing 90% inhibition of clonal growth (ID90) by less than 500 units of TNF per ml of culture fluid. In contrast, all 13 nonmalignant specimens tested clustered at the resistant end of the TNF response spectrum, with ID90 values being greater than 5000 units of TNF per ml of culture fluid. This differential sensitivity to TNF was seen in three cases in which malignant and nonmalignant breast epithelial tissues from the same patient were studied. To investigate the mechanism of resistance to TNF by normal cells, the presence of receptors for TNF was determined. Five of six cultures showed specific binding of 125I-labeled TNF and there was no relationship between the degree of resistance and the degree of specific binding. Simultaneous comparison of tumor responsiveness to doxorubicin and TNF revealed a positive correlation in ID90 values; these results may have important implications for the clinical use of TNF in cancer patients heavily pretreated with doxorubicin.

A phase I study of recombinant interleukin 2 plus recombinant beta-interferon.

Interleukin 2 (IL-2) therapies have antitumor activities against several neoplasms. In vitro these activities are enhanced by beta-interferon (IFN-beta). Therefore, we initiated a Phase I trial with a combination of IL-2 and IFN-beta three times weekly. The IFN-beta was administered i.v. Initially, the IL-2 was administered s.c. However, neutralizing antibody to the IL-2 developed in five patients, and the route of administration of the IL-2 was changed to i.v. Forty-seven patients were entered on the study. The maximum tolerated doses for the combination given i.v. were 5 x 10(6) units/m2 of IL-2 and 10 x 10(6) units/m2 of IFN-beta. Dose-limiting toxicities were profound fatigue/decreased performance status, anorexia/weight loss, depression, and arthralgias. Hypotension, exfoliative skin rash, thrombocytopenia, diarrhea, temperature greater than 40.6 degrees C, and peripheral edema were rarely dose limiting. Thirty-two patients were evaluable for response. After 4 weeks of treatment, 21 patients had stable disease, three patients had a minor response, and one patient had a partial response. Significant lymphokine-activated killer cell (LAK) activity was seen in seven patients (22%) and required 5 x 10(6) units/m2 of IL-2. Those who had progressive disease had significantly less LAK activity than those with either stable disease or a response. This therapy also induced more than 60 units/ml of endogenous gamma-interferon 4 h after the i.v. IL-2 administration. This study demonstrates that (a) intermittent i.v. bolus IL-2 therapy can generate LAK activity, (b) LAK activity may be associated with an antitumor response, (c) significant levels of gamma-interferon are induced by this therapy, and (d) IL-2 and IFN-beta given three times weekly i.v. is both tolerable and biologically active. The recommended Phase II dose is 5 x 10(6) units/m2 of IL-2 plus 6 x 10(6) units/m2 of IFN-beta.

Mixed germ-cell tumor of the pineal region. Case report.

The case is presented of a 15-year-old boy with a mixed nongerminomatous germ-cell tumor of the pineal region associated with elevated cerebrospinal fluid and serum levels of the beta subunit of human chorionic gonadotropin. Treatment consisted of initial subtotal resection followed by radiotherapy and systemic chemotherapy with cisplatin, vinblastine, and bleomycin. The patient is alive without evidence of tumor 37 months after his initial diagnosis. A literature review of intracranial embryonal carcinoma and choriocarcinoma provided the rationale for a combined-modality approach to this otherwise lethal neoplasm.