Clinical effects and pharmacokinetics of the fusion protein PIXY321 in children receiving myelosuppressive chemotherapy

A hemopoietin with the ability to accelerate both platelet and granulocyte recovery after intensive chemotherapy would have great clinical utility. The recombinant fusion protein composed of human granulocyte-macrophage colony-stimulating factor and interleukin-3 (PIXY321), showed some promise in early adult trials. However, studies for pediatric patients are limited, and there are no systematic data on the pharmacokinetics of PIXY321 given over prolonged periods at current dosage levels. Purpose: To determine the safety, clinical effects and plasma concentrations of increasing doses of PIXY321 in children treated with myelosuppressive chemotherapy. Methods: A total of 39 children with relapsed or high-risk solid tumors were enrolled in this phase I/II study. PIXY321 was administered once or twice daily by subcutaneous injection in total doses of 500 to 1000 μg/m² per day for 14 days after each course of chemotherapy with ifosfamide, carboplatin, and etoposide (ICE). Pharmacokinetic studies were performed on day 1 of the first course in 33 patients and repeated on day 14 in 13 patients (once-daily schedule only). Results: Although mild local skin reactions and fever were frequent, no dose-limiting toxicity was identified at the maximum dose studied (1000 μg/m² per day). There were no statistically significant differences in chemotherapy-induced hematologic toxicity with increasing doses of PIXY321 or with twice-daily vs once-daily dosing. On day 1, the median PIXY321 clearance was 657 ml/min per m² (range 77–1804 ml/min per m²) and the median half-life was 3.7 h (range 2.1–20.8 h). On day 14, clearance increased in all patients studied (median increase 63%), with a corresponding decrease in the median 12-h concentration (from 1.2 to 0.25 ng/ml). Maximum concentrations were <1 ng/ml in 81% of patients, and only two patients had maximum plasma concentrations equivalent to those required for consistent activity in vitro. Conclusions: The recombinant fusion protein PIXY321 proved safe in children treated with myelosuppressive ICE chemotherapy but had no demonstrable clinical benefits. The pharmacokinetic studies suggest that the observed lack of hematologic benefit may be explained by low plasma concentrations resulting from increased clearance with prolonged administration. Moreover, the significant increase in PIXY321 systemic clearance in the absence of increased circulating myeloid cells suggests that the upregulation of either extravascular compartment hematopoietic progenitor cells or nonhematopoietic cells may play an important role in controlling circulating concentrations of this unique cytokine. These findings highlight the importance of a thorough assessment of the systemic disposition of cytokines when determining the dose and schedule necessary to achieve clinical activity in patients. Received: 29 January 1997 / Accepted: 9 May 1997     

In Vitro Effects of Retinoids on the Proliferation and Differentiation Features of Epstein-Barr Virus-Immortalized B Lymphocytes

Retinoids have been shown to be effective in the chemoprevention and treatment of certain human malignancies. In this review, we will summarize our recent results concerning the effects of retinoids on the proliferation and differentiation of Epstein-Barr virus (EBV)-immortalized lymphoblastoid B-cell lines (LCLs), an in vitro model of EBV-related lymphoproliferative disorders arising in immunosuppressed hosts. Retinoids proved to be powerful inhibitors of the proliferation of EBV-infected LCLs in vitro, with 13-cis-retinoic acid (RA), all-trans-RA, and 9-cis-RA being the most effective compounds. Of note, retinoid-induced growth arrest in vitro appears irreversible at drug concentrations (10-^-6 mol/L) which may be reached in man after oral systemic therapy. The antiproliferative activity exerted by retinoids on LCLs is a generalized phenomenon usually associated with a progressive accumulation in G₀/G₁ phases of treated cells. The strong upregulation of p27^Kipl invariably observed in cells exposed to retinoids may contribute to the decreased number of cycling cells, probably by inhibiting the transition from the G₁ to S phase. Moreover, we obtained evidence indicating that the antiproliferative effects of retinoids are not dependent on the induction of terminal differentiation of EBV-immortalized B lymphocytes. In fact, the modifications induced by retinoids relative to LCL morphology, phenotype (downregulation of CD19, HLA-DR, and s-Ig, and upregulation of CD38 and c-Ig), and IgM production were highly variable among the lines tested and often only slightly relevant. Finally, the antiproliferative activity exerted by retinoids on LCLs is not mediated by a direct modulation of viral latent antigens, since EBNA-2 and LMP-1 downregulation was a late event detected only in some cell lines. These results indicate that retinoids may be useful in the medical treatment of EBV-related lymphoproliferative disorders of immunosuppressed patients, particularly in the earlier phases of these diseases.     

Polymorphisms of interleukin (IL)-1α, IL-1β, IL-6, IL-10, and IL-18 and the risk of ovarian cancer

OBJECTIVE: Recent studies of ovarian cancer have suggested a role for inflammation in carcinogenesis. Data from a population-based case-control study in Hawaii were examined to assess the relation between polymorphisms in cytokines involved with the inflammatory response, specifically members of the interleukin (IL) family and the incidence of ovarian cancer. PATIENTS AND METHODS: The analysis of 182 epithelial ovarian cancer cases and 219 controls focused on the polymorphisms in the following genes: IL-1alpha, IL-1beta, IL-6, IL-10, and IL-18. Genotype data were obtained from blood samples collected in participants' homes, and reproductive, demographic, and lifestyle histories were collected during interview. RESULTS: There were no significant odds ratios (ORs) for ovarian cancer by allelic variants in any of the IL genes after adjusting for age, ethnicity, education, oral contraceptive pill use, pregnancy, and history of tubal ligation. Although there was a significantly reduced risk of ovarian cancer risk among women with an IL-1alpha (-4845) T allele compared to women with two G alleles (OR: 0.59; 95% confidence interval: 0.37-0.97) after adjustment for age and ethnicity, the trend was not significant (p = 0.10). Further examination of the data suggested that women with at least one IL-18 variant allele (a G to C transition at position -137) were at significantly decreased risk of advanced ovarian cancer (OR: 0.51; 95% confidence interval: 0.28-0.90) compared to women with the IL-18 GG genotype. There was a significant difference in the risk of ovarian cancer associated with the IL-18 C allele by stage at diagnosis (p = 0.04 for homogeneity in the ORs): cases with IL-18 GC or CC genotypes were less likely to be diagnosed at regional/distant stages. Analysis of the data within ethnic subgroups revealed a significant positive association of the heterozygous IL-18 GC genotype with ovarian cancer risk among Native Hawaiian women (OR: 9.96; 95% CI: 1.88-52.90). The OR for ovarian cancer was not significant for Native Hawaiian women homozygous for the IL-18 C allele, but only one case and control had the IL-18 CC genotype. CONCLUSIONS: Overall, this study does not support an association of selected IL-1alpha, IL-1beta, IL-6, IL-10, or IL-18 polymorphisms with the risk for ovarian cancer. However, the IL-18 G137C variant may be a marker for ovarian cancer progression or metastasis.     

Abnormal vascular tone in infants and children with lung hypoplasia: Findings from cardiac catheterization and the response to chronic therapy.

OBJECTIVE: We describe four cases of chronic pulmonary hypertension in infants and children with chronic lung disease and pulmonary hypoplasia due to severe congenital diaphragmatic hernia (CDH) or congenital cystic adenomatoid malformation (CCAM). We report data from cardiac catheterization under various conditions: baseline respiratory support and room air, hyperoxic and inhaled nitric oxide challenge. We further report cardiac catheterization measures after chronic pulmonary vasodilator therapy with sildenafil alone or a combination of sildenafil and inhaled nitric oxide (three patients). DESIGN: Case series. SETTING: Tertiary academic center. PATIENTS: Infants and children ages 0-11 yrs with CDH (n = 3) or CCAM (n = 1) with evidence of chronic pulmonary hypertension by echocardiogram and cor pulmonale (n = 3). INTERVENTIONS: Catheterization and pulmonary vasodilator therapy. MEASUREMENTS AND MAIN RESULTS: Pulmonary vascular resistance, pulmonary arterial pressure, and changes in these measures were assessed. A 20% change in pulmonary vascular resistance was considered a clinically significant response. Ten catheterizations were performed in four patients. All patients had elevated pulmonary vascular resistance and pulmonary arterial pressures at initial catheterizations and significant vasodilation during inhaled nitric oxide. CONCLUSIONS: Chronic lung disease following pulmonary hypoplasia from CDH and CCAM is associated with abnormal pulmonary vascular tone in infants and children with evidence of chronic pulmonary hypertension. Chronic pulmonary vasodilator therapy may improve pulmonary vascular function and enhance lung growth in infants and children who are treated during their period of potential for rapid lung growth.     

Effect of nolomirole on monocrotaline-induced heart failure.

Neurohormonal activation has been shown to be a major factor in congestive heart failure progression and mortality. The beneficial effects obtained in clinical trials with angiotensin converting enzyme (ACE) inhibitors, beta-blockers and aldosterone antagonists have confirmed this hypothesis. 5,6-Diisobutirroyloxy-2-methyl-aminotetraline hydrochloride (nolomirole) is a selective agonist of prejunctional D(2)-dopaminergic and alpha(2)-adrenergic receptors. The stimulation of these receptors inhibits catecholamine release from sympathetic nerve endings. To confirm that this mechanism can be useful in congestive heart failure, we studied the effects of nolomirole on monocrotaline-induced congestive heart failure. The ACE inhibitor trandolapril was used as reference compound. Rats were given single intraperitoneal injection of either saline (control group; n=20) or monocrotaline (50 mg kg(-1)). Three days later, the monocrotaline-treated animals were randomly allocated (n=50 per group) to oral treatment with distilled water (vehicle group), nolomirole (0.25 mg kg(-1)) twice a day, or trandolapril (0.3 mg kg(-1)) once a day up to sacrifice. On the fourth week after monocrotaline injection, animals with signs of congestive heart failure were sacrificed for evaluation of heart hypertrophy and neuroendocrine alterations. Atrial natriuretic peptide (ANP) and alderosterone were determined by radioimmunoassay in plasma. Tissue norepinephrine concentration was quantified by high-pressure liquid chromatography. Nolomirole and trandolapril significantly reduced (a) hypertrophy of right atria and ventricles, (b) plasma levels of ANP and presence of pleural/peritoneal effusions and (c) norepinephrine depletion of right ventricle. These findings confirmed that nolomirole, like trandolapril, is able to attenuate the heart failure signs in the monocrotaline-induced congestive heart failure model.     

HMGB1: A signal of necrosis

When tissues are damaged, they usually heal. The cellular responses towards healing require the prior recognition that damage has occurred. High Mobility Group Box 1 protein (HMGB1) is a ubiquitous nuclear protein that is passively released by cells that have died in a traumatic, non-programmed way (necrosis). Several receptors for HMGB1 exist, and upon binding HMGB1 they alert leukocytes to extravasate from the blood into the affected tissue, trigger adaptive immunity and promote the migration and proliferation of cells (including stem cells) to repair the damaged tissue. Significantly, apoptotic cells modify their chromatin so as to bind HMGB1, which is not released. Several cell types (in particular inflammatory cells) when distressed have the ability to secrete HMGB1 actively, via a dedicated pathway, and thus produce a damage signal without dying. Because of its powerful activities, HMGB1 is involved in several disorders, including autoimmune ones.     

A New Method to Detect Directly in Culture Cell Surface Membrane Immunoglobulins

Abstract

An ELISA assay is described for the measurement of the smIgG. The method is based on the detection of cell-smIgG directly on the same microplate used for the culture. The cells, preincubated at 37°C for one hour, were cultured in the presence of S-ConA and serum-free medium for two days. Using this strategy, the background noise due to non specific adsorbtion of IgG to plastic wells and cytophilic antibodies was eliminated. The cells in the presence of S-ConA and serum-free medium adhered to the plastic wells, and the cell-smIgG were detected using an anti-human IgG covalently linked to alkaline phosphatase or its F(ab')₂ fragment. The possibility of measuring the modulation of the expression of the cell-smIgG without any additional manipulation is stressed.