Combination of ganciclovir and granulocyte-macrophage colony-stimulating factor in the treatment of cytomegalovirus retinitis in AIDS patients. The ACTG 073 Team

Retrospective case analysis of antiviral therapies for HHV-6 encephalitis after hematopoietic stem cell transplantation

Human herpesvirus 6 (HHV-6) is one of the most common causes of encephalitis in allogeneic hematopoietic stem cell transplant (HCT) recipients and is associated with significant morbidity and mortality. There are no FDA-approved treatments specifically for HHV-6 encephalitis; HHV-6 disease is typically treated with CMV antivirals. A review of antiviral medications used to treat HHV-6 encephalitis was conducted by aggregating data from case reports found on PubMed. Articles were included if they examined at least one HCT patient diagnosed with HHV-6 encephalitis and described their treatment course and outcome. Key data were abstracted from 123 cases described in 52 studies. The proportion of patients with encephalitis who died or developed sequelae was 63.6% among ganciclovir monotherapy recipients (n = 44), 55.3% among foscarnet monotherapy recipients (n = 47), and 37.5% among recipients of combination therapy with foscarnet and ganciclovir (n = 32). Logistic regression revealed that recipients of foscarnet (OR 4.286, 95% CI 1.235-14.877, P = .022) and ganciclovir (OR 5.625, 95% CI 1.584-19.975, P = .008) monotherapies were more likely to develop sequelae compared to recipients of combination therapy, respectively. In multivariate analyses, non-cord blood transplant was identified as an independent risk factor for developing sequelae after receiving ganciclovir monotherapy (OR 5.999, 95% CI 1.274-28.254, P = .023). There was no difference in mortality between patients who received combination therapy and those who received monotherapy. In conclusion, combination therapy with foscarnet and ganciclovir may reduce sequelae, but not mortality, secondary to HHV-6 encephalitis.

The role of ganciclovir for the management of cytomegalovirus retinitis in HIV patients: Pharmacological review and update on new developments

OBJECTIVE

To review the pharmacology and pharmacokinetics of intravenous, oral and intraocular ganciclovir, and to discuss the role of these various formulations in the management of cytomegalovirus (CMV) retinitis in AIDS patients.

DATA SOURCES

A MEDLINE search (1987 through November 1995) of English-language literature using the main medical subject headings 'ganciclovir' and 'cytomegalovirus', and the subheading 'acquired immunodeficiency syndrome'. Relevant articles were also selected from references of identified articles. Abstracts from recent medical conferences of infectious diseases, pharmacology and human immunodeficiency virus were screened for additional data.

STUDY SELECTION AND DATA EXTRACTION

All articles and abstracts discussing the use of ganciclovir for the management or prophylaxis of CMV retinitis in AIDS patients were considered for inclusion. Pertinent information, as judged by the authors, was selected and synthesized for discussion.

DATA SYNTHESIS

Ganciclovir has demonstrated virustatic activity against CMV, and is often administered 5 mg/kg intravenously every 12 h as first-line therapy for CMV retinitis. Intravenous maintenance therapy at 5 mg/kg daily is usually effective at delaying retinitis progression for approximately 60 to 70 days. Neutropenia and thrombocytopenia are observed frequently, often necessitating interruption or discontinuation of therapy. Local drug administration may delay disease progression even further, and may be considered for patients who are intolerant to or failing intravenous therapy. However, systemic ganciclovir should be encouraged to reduce the risk of developing contralateral eye or end-organ CMV disease. Oral ganciclovir at 1 g tid is almost as effective as intravenous ganciclovir 5 mg/kg/day in delaying retinitis progression and is associated with fewer line-related complications. Absorption, drug interactions, cost and compliance should also be considered.

CONCLUSIONS

Until recently, ganciclovir was available only for intravenous use. Recent developments allow for intraocular and oral administration of this agent. A clear understanding of the advantages and disadvantages of these new formulations is required in order to select the most appropriate product for managing CMV retinitis in AIDS patients.

Bioavailability of orally administered rhGM-CSF: a single-dose, randomized, open-label, two-period crossover trial

Background

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is usually administered by injection, and its oral administration in a clinical setting has been not yet reported. Here we demonstrate the bioavailability of orally administered rhGM-CSF in healthy volunteers. The rhGM-CSF was expressed in Bombyx mori expression system (BmrhGM-CSF).

Methods and Findings

Using a single-dose, randomized, open-label, two-period crossover clinical trial design, 19 healthy volunteers were orally administered with BmrhGM-CSF (8 µg/kg) and subcutaneously injected with rhGM-CSF (3.75 µg/kg) respectively. Serum samples were drawn at 0.0h, 0.5h ,0.75h,1.0h,1.5h,2.0h ,3.0h,4.0h,5.0h,6.0h,8.0h,10.0h and 12.0h after administrations. The hGM-CSF serum concentrations were determined by ELISA. The AUC was calculated using the trapezoid method. The relative bioavailability of BmrhGM-CSF was determined according to the AUC ratio of both orally administered and subcutaneously injected rhGM-CSF. Three volunteers were randomly selected from 15 orally administrated subjects with ELISA detectable values. Their serum samples at the 0.0h, 1.0h, 2.0h, 3.0h and 4.0h after the administrations were analyzed by Q-Trap MS/MS TOF. The different peaks were revealed by the spectrogram profile comparison of the 1.0h, 2.0h, 3.0h and 4.0h samples with that of the 0.0h sample, and further analyzed using both Enhanced Product Ion (EPI) scanning and Peptide Mass Fingerprinting Analysis. The rhGM-CSF was detected in the serum samples from 15 of 19 volunteers administrated with BmrhGM-CSF. Its bioavailability was observed at an average of 1.0%, with the highest of 3.1%. The rhGM-CSF peptide sequences in the serum samples were detected by MS analysis, and their sizes ranging from 2,039 to 7,336 Da.

Conclusions

The results demonstrated that the oral administered BmrhGM-CSF was absorbed into the blood. This study provides an approach for an oral administration of rhGM-CSF protein in clinical settings.

Trial Registration

www.chictr.orgChiCTR-TRC-00000107

Large-scale purification of human granulocyte-macrophage colony-stimulating factor expressed in Bombyx mori pupae

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) acts on many different kinds of cells, including monocytes, macrophages, granulocytes, eosinophils, and multipotential stem cells. To explore further explore pharmaceutical action, we expressed hGM-CSF by the Bombyx mori nucleopolyhedrovirus expression system in silkworm pupae. However, purifying recombinant proteins from silkworm pupae on a large scale has been a big challenge. To establish purification methods suitable for mass production, we tried two crude preparation methods: (NH4)2SO4 fractional precipitation and isoelectric precipitation with a combination of gel filtration and ion-exchange chromatography. The isoelectric precipitation method was found to be more efficient. With this method, we eventually obtained approx 11.7 mg of 95% pure product from 1000 g of infected silkworm pupae. The recovery of purified protein was greatly increased, by approx 40%, compared with the other method. The biologic activity of this protein was determined up to 9.0 x 106 colony-forming units/mg in the final purified product.

Expression, purification and characterization of human GM-CSF using silkworm pupae (Bombyx mori) as a bioreactor

To date, many recombinant proteins have been expressed in Bombyx mori cells or silkworm larvae, apart from in pupae. Silkworm pupae may be more suitable for the expression of heterologous proteins as a bioreactor. If maintained at an appropriate temperature, silkworm pupae could be inoculated with recombinant baculovirus for the expression of a protein of interest. In this study, human granulocyte-macrophage colony-stimulating factor was successfully expressed in silkworm pupae using B. mori nucleopolyhedrovirus, purified and characterized with respect to its physico-chemical properties. The target protein expressed had an apparent molecular mass of 29 kDa and an isoelectric point of 5.1. The protein was purified using three chromatographic steps with a final recovery of 10.3%. Finally, approximately 3.5mg of the protein was obtained with a biological activity of up to 8.4 x 10(6) cfu mg(-1). The results of this study suggest that silkworm pupae represent a convenient and low-cost bioreactor for the expression of heterologous proteins.

Posterior segment manifestations of HIV/AIDS

The ocular posterior segment manifestations of AIDS may be divided into four categories: retinal vasculopathy, unusual malignancies, neuro-ophthalmologic abnormalities, and opportunistic infections. Microvasculopathy is the most common manifestation. Opportunistic infections, particularly cytomegalovirus retinitis and progressive outer retinal necrosis, are the most likely to result in visual loss due to infection or subsequent retinal detachment. Diagnosis and treatment are guided by the particular conditions and immune status of the patient.

Use of cytokines in human immunodeficiency virus-infected patients: colony-stimulating factors, erythropoietin, and interleukin-2

The recombinant human cytokines granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin, and interleukin-2 (IL-2) have been manufactured and licensed. Studies have been carried out that investigate the use of G-CSF and GM-CSF to reverse leukopenia, as adjunctive therapy for HIV-associated infections and for novel approaches to treat HIV infection, including stem cell mobilization. In addition, studies that identified the role of erythropoietin in the management of anemia have been performed. Furthermore, the abilities of G-CSF and erythropoietin to permit the continued use of marrow suppressive agents that are key in managing HIV infection have been assessed. The aim of this review is to summarize these studies and to describe the reports that evaluate the use of IL-2 to enhance elevation of CD4 cell counts mediated by highly active antiretroviral therapy. This summary is important to the treating clinician in that it identifies the optimal use of these cytokines in current clinical practice as well as their potential future roles.

Comparative tolerability of therapies for cytomegalovirus retinitis

Cytomegalovirus (CMV) retinitis is a potentially sight-threatening complication of advanced HIV infection. The acute infection can be controlled with one of several therapies, including intravenous ganciclovir, foscarnet or cidofovir, slow release ganciclovir intraocular implants or serial intraocular injections of ganciclovir or foscarnet. The initial induction course of therapy is typically followed by lifelong maintenance therapy. In addition to the aforementioned treatments, oral ganciclovir and intravitreal fomivirsen injections are other options for maintenance therapy. The choice of agent must take into consideration factors such as comparative short and long term toxicity of the agents, route of administration and the possible need for indwelling catheters, administration time, cost and protection afforded against systemic dissemination of CMV infection. Possible drug interactions and additive toxicities of other agents needed for the management of the underlying HIV infection must also be taken into consideration. These factors can affect the tolerability of therapy as well as the quality of life of the patient. Relapse or progression of CMV retinitis may be caused by either inadequate drug concentrations at the site of the infection or by drug resistance. This may necessitate either an increase in drug dosage, a change in route of administration or a change to an alternative agent. All of these approaches can increase the risk of toxicity of the therapy. With the initiation of highly active antiretroviral therapy and partial reconstitution of the immune system, some patients have been able to successfully discontinue anti-CMV maintenance therapy, thereby decreasing long term drug toxicity. Determination of the patient predictors of success of this approach is an active area of research.

Management strategies for patients with cytomegalovirus retinitis

Each of the available antiviral agents has significant advantages and disadvantages, and the choice of therapy must include consideration of the extent and location of the eye disease, the patient's lifestyle and medical history, and the potential for drug interactions with the many other medications that a patient with advanced AIDS may be receiving. Treatment of CMV retinitis requires the active participation of several dedicated health care providers: the primary care physician, the ophthalmologist, nurses, and social workers. All are integral parts of a clinical treatment team engaged in providing optimal therapy. Most important, it is critical for patients to be involved with their own health care. Patients should be taught to recognize early signs of decreased vision and should be involved in important decision-making steps for their own treatment.

Priming of neutrophil and monocyte activation in human immunodeficiency virus infection. Comparison of granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor and interferon-gamma

Activation of human blood neutrophils and monocytes for enhanced release of toxic oxygen radicals may take place after priming with several cytokines including hematopoietic growth factors. The potential impact of human immunodeficiency virus (HIV) on this response and the relative potency of various cytokines remains unclear. Blood neutrophils and monocytes were isolated from 25 HIV outpatients with variable immunodeficiency. Oxidative burst response upon stimulation with N-formyl-methionyl-leucyl-phenylalanine was assessed in neutrophils after priming with granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma (IFN-g), and in monocytes after priming with GM-CSF and IFN-g. Monocyte oxidative burst responses were not changed in patients or controls. In contrast, following priming with IFN-g, GM-CSF or medium (but not G-CSF) the neutrophils in HIV patients with CD4 counts > 200 x 10(9)/L exhibited a significantly higher chemiluminescence response than was seen in healthy age-matched controls, whereas the response in patients with lower CD4 counts was not different from controls. At comparable concentrations, GM-CSF induced a significantly higher priming than G-CSF and IFN-g. A significant positive correlation between CD4 counts and priming activity of GM-CSF and IFN-g on neutrophils was observed. We conclude that neutrophils in HIV infection have a normal or enhanced response to the oxidative metabolism priming activity of hematopoietic growth factors in vitro, whereas priming effect on monocytes was not seen.