Efficacy of enzyme replacement therapy in Fabry disease.

Enzyme replacement therapy has recently been introduced to treat Fabry disease, a rare X-linked lysosomal storage disorder. The disease occurs due to deficient activity of alpha-galactosidase A, leading to progressive accumulation of globotriaosylceramide in multiple organs and tissues. Renal, cardiac and cerebrovascular manifestations of the disease result in premature death in both hemizygous males and heterozygous females. This paper outlines the clinical signs, symptoms and diagnosis of Fabry disease, and the development of the two available enzyme replacement therapies -- agalsidase alfa and agalsidase beta. Agalsidase alfa and agalsidase beta are produced in a human cell line and in Chinese hamster ovary cells, respectively, resulting in products with the same amino acid sequence as the native human enzyme, but with different patterns of glycosylation. Correct post-translational glycosylation is important in terms of the pharmacokinetics, biodistribution, clinical efficacy and tolerability of genetically engineered protein therapeutics. Differences in glycosylation, which may affect immunogenicity and mannose-6-phosphate receptor-mediated cellular internalisation of administered enzyme, possibly account for the differences in dosing, clinical effects and safety profiles reported for agalsidase alfa and agalsidase beta.

The novel ss469415590 variant predicts virological response to therapy in patients with chronic hepatitis C virus type 1 infection.

BACKGROUND: A novel dinucleotide variant TT/∆G (ss469415590) has been associated with hepatitis C virus clearance. AIM: To assess the role of the ss469415590 variant, compared with the known IL28B polymorphisms (rs8099917, rs12979860 and rs12980275) for predicting virological response to therapy in chronic hepatitis C, and its association with the CXCL10 chemokine serum levels - a surrogate marker of interferon-stimulated genes activation. METHODS: Multivariate analysis of factors predicting rapid and sustained virological response in 280 consecutive, treatment-naïve, nondiabetic, Caucasian patients with chronic hepatitis C treated with peginterferon alpha and ribavirin. RESULTS: In hepatitis C virus genotype 1, the OR (95% CI) for rapid and sustained virological response for the wild-type ss469415590 TT was 9.88 (1.99-48.99) and 7.25 (1.91-27.51), respectively, similar to those found for rs12979860 CC [9.55 (1.93-47.37) and 6.30 (1.71-23.13)] and for rs12980275 AA [9.62 (1.94-47.77] and 7.83 (2.02-30.34)], but higher than for rs8099917 TT [4.8 (1.73-13.33) and 4.75 (2.05-10.98)]. In hepatitis C virus genotype 1, mean (SD) CXCL10 levels in patients with the TT/TT, TT/∆G and ∆G/∆G variants were, respectively, 355.1 (240.6), 434.4 (247.4) and 569.9 (333.3) (P = 0.04). In patients with genotypes 2 and 3 no significant association was found for TT/∆G with viral response. The predictive value of ss469415590 was stronger in patients with advanced fibrosis. CONCLUSIONS: The novel IL28B variants at marker ss469415590 predict response to IFN alpha in chronic hepatitis C patients, especially in those with advanced fibrosis. Their determination may be superior to that of known IL28B variants for patient management using IFN-based regimens.

A Guide to Workforce Drug Testing in Iowa, October 13, 2010

The purpose of the State of Iowa’s drug testing law—Iowa Code Section 730.5 (& Administrative Code Section 641)—is to enhance worker safety, by creating workplaces that are free of drugs and substance abuse. One tool available to private sector employers is drug testing (inclusive of alcohol testing), that often is coupled with educational efforts as part of a comprehensive drug-free workplace program. Each employer must first decide if drug and/or alcohol testing is appropriate for them. Under Iowa law, workplace drug or alcohol testing is optional for private sector employers. Federal laws or regulations governing drug or alcohol testing supersede state law in Iowa.

Reducing Prescription Drug Abuse in Iowa, January 5, 2011

Prescription drug abuse is the nation’s fastest-growing drug problem, as outlined by the White House Office of National Drug Control Policy’s 2011 national plan “Responding to America’s Prescription Drug Abuse Crisis.” The urgency of the challenge is underscored in other reports, including a recent analysis by the Centers for Disease Control (CDC) that said: “Overdoses involving prescription painkillers are at epidemic levels and now kill more Americans than heroin and cocaine combined.” According to the CDC, more than 40 people die in America every day from overdoses involving narcotic pain relievers such as hydrocodone (Vicodin), oxycodone (Oxycontin), methadone and oxymorphone (Opana). In Iowa, the situation is similar, at least in some ways. Prescription drug abuse is one of the fastest-growing forms of substance abuse in our state too, though its scope is smaller and on a more manageable scale when compared with most other states. The Iowa Department of Public Health, Bureau of Vital Statistics, reports the drug overdose deaths of at least 130 Iowans over the last three years (2008-2010) due to non-heroin opioids (i.e., prescription pain relievers such as oxycodone, hydrocodone and methadone), nearly as many as for the previous eight years combined (149 from 2000-2007).

Hepatitis B virus infection is associated with impaired immunological recovery during antiretroviral therapy in the Swiss HIV cohort study.

Hepatitis B virus (HBV) infection is a major cause of morbidity and mortality in human immunodeficiency virus (HIV)-infected patients worldwide. It is unclear whether HIV-related outcomes are affected by HBV coinfection. We compared virological suppression and immunological recovery during antiretroviral therapy (ART) of patients of different HBV serological status in the Swiss HIV Cohort Study. CD4 cell recovery during ART was significantly impaired in hepatitis B surface antigen-positive patients and in those with anti-hepatitis B core antigen alone compared with HBV-uninfected patients, despite similar virological efficacy of ART. CD4 increase in patients with resolved HBV infection was similar to that in HBV-uninfected individuals.

A Guide to Workplace Drug Testing in Iowa, October 13, 2010

The purpose of the State of Iowa’s drug testing law—Iowa Code Section 730.5 (& Administrative Code Section 641)—is to enhance worker safety, by creating workplaces that are free of drugs and substance abuse. One tool available to private sector employers is drug testing (inclusive of alcohol testing), that often is coupled with educational efforts as part of a comprehensive drug-free workplace program. Each employer must first decide if drug and/or alcohol testing is appropriate for them. Under Iowa law, workplace drug or alcohol testing is optional for private sector employers. Federal laws or regulations governing drug or alcohol testing supersede state law in Iowa.

Therapeutic drug monitoring in cancer - Are we missing a trick?

Therapeutic drug monitoring (TDM) can be defined as the measurement of drug in biological samples to individualise treatment by adapting drug dose to improve efficacy and/or reduce toxicity. The cytotoxic drugs are characterised by steep dose-response relationships and narrow therapeutic windows. Inter-individual pharmacokinetic (PK) variability is often substantial. There are, however, a multitude of reasons why TDM has never been fully implemented in daily oncology practice. These include difficulties in establishing appropriate concentration target, common use of combination chemotherapies and the paucity of published data from pharmacological trials. The situation is different with targeted therapies. The large interindividual PK variability is influenced by the pharmacogenetic background of the patient (e.g. cytochrome P450 and ABC transporters polymorphisms), patient characteristics such as adherence to treatment and environmental factors (drug-drug interactions). Retrospective studies have shown that targeted drug exposure correlates with treatment response in various cancers. Evidence for imatinib currently exists, others are emerging for compounds including nilotinib, dasatinib, erlotinib, sunitinib, sorafenib and mammalian target of rapamycin (mTOR) inhibitors. Applications for TDM during oral targeted therapies may best be reserved for particular situations including lack of therapeutic response, severe or unexpected toxicities, anticipated drug-drug interactions and concerns over adherence treatment. There are still few data with monoclonal antibodies (mAbs) in favour of TDM approaches, even if data showed encouraging results with rituximab and cetuximab. TDM of mAbs is not yet supported by scientific evidence. Considerable effort should be made for targeted therapies to better define concentration-effect relationships and to perform comparative randomised trials of classic dosing versus pharmacokinetically-guided adaptive dosing.

Assessment of a sheep animal model to optimize photodynamic therapy in the oesophagus

Background and Objectives: Precursor lesions of oesophagus adenocarcinoma constitute a clinical dilemma. Photodynamic therapy (PDT) is an effective treatment for this indication, but it is difficult to optimise without an appropriate animal model. For this reason, we assessed the sheep model for PDT in the oesophagus with the photosensitiser meta-(tetra-hydroxyphenyl) chlorin (mTHPC). Materials and Methods: Twelve sheep underwent intravenous mTHPC injection, blood sampling and fluorescence measurements. mTHPC's pharmacokinetics was measured in vivo and in plasma by fluorescence spectroscopy. Biopsies of sheep oesophagus were compared to corresponding human tissue, and the mTHPC's biodistribution was studied under fluorescence microscopy. Finally, the sheep oesophageal mucosa was irradiated, 4 days after mTHPC's injection. Results: Histologically, the sheep and human oesophagus were closely comparable, with the exception of additional fatty tissue in the sheep oesophagus. mTHPC's pharmacokinetics in sheep and human plasmas were similar, with a maximum of concentration in the sheep 10 hours after i.v. injection. mTHPC's pharmacokinetics in vivo reached its maximum after 30-50 hours, then decreased to background levels, as in humans under similar conditions. Two days after injection, mTHPC was mainly distributed in the lamina propria, followed by a penetration into the epithelium. The sheep and human tissue sensitivity to mTHPC PDT was similar. Conclusion: In conclusion, this model showed many similarities with humans as to mTHPC's plasma and tissue pharmacokinetics, and for tissue PDT response, making it suitable to optimise oesophagus PDT. Lasers Surg. Med. 41:643-652,2009. (C) 2009Wiley-Liss,Inc.

Assessment of therapeutic benefit of antiviral therapy in chronic hepatitis C: is hepatic venous pressure gradient a better end point?

Chronic hepatitis C is a major healthcare problem. The response to antiviral therapy for patients with chronic hepatitis C has previously been defined biochemically and by PCR. However, changes in the hepatic venous pressure gradient (HVPG) may be considered as an adjunctive end point for the therapeutic evaluation of antiviral therapy in chronic hepatitis C. It is a validated technique which is safe, well tolerated, well established, and reproducible. Serial HVPG measurements may be the best way to evaluate response to therapy in chronic hepatitis C.

Enteral nutrition as primary therapy in Crohn's disease

The developments in enteral feeding for Crohn's disease in the past decade are critically reviewed. The advent of amino acid based chemically defined elemental diets signalled the end of 'total bowel rest' in the management of these patients. Subsequently, controlled clinical trials showed that elemental diets were as effective as corticosteroids in inducing clinical remission in patients with acute exacerbations of Crohn's disease. The later use of peptide based elemental diets, in Crohn's disease produced somewhat conflicting results. The initial uncontrolled studies suggest that polymeric whole protein diets might also be effective in the management of acute exacerbations of the disease, casting in turn doubts concerning the role of dietary antigens in the pathogenesis of Crohn's disease. Results of controlled studies comparing the use of elemental and polymeric diets as primary therapy in Crohn's disease have, however, also produced conflicting results. The results of one recent controlled trial in which

Chronic hepatitis B reactivation following infliximab therapy in Crohn's disease patients: need for primary prophylaxis.

Background: There is little information about the effect of infliximab on the clinical course of liver disease in Crohn's disease patients with concomitant hepatitis B virus (HBV) infection. Theoretically, immunosuppression induced by infliximab will facilitate viral replication which could be followed by a flare or exacerbation of disease when therapy is discontinued. There are no specific recommendations on surveillance and treatment of HBV before infliximab infusion. Two cases of severe hepatic failure related to infliximab infusions have been described in patients with rheumatic diseases. Patients and methods: Hepatitis markers (C and B) and liver function tests were prospectively determined to 80 Crohn's disease patients requiring infliximab infusion in three hospitals in Spain. Results: Three Crohn¿s disease patients with chronic HBV infection were identified. Two of the three patients with chronic HBV infection suffered severe reactivation of chronic hepatitis B after withdrawal of infliximab therapy and one died. A third patient, who was treated with lamivudine at the time of infliximab therapy, had no clinical or biochemical worsening of liver disease during or after therapy. From the remaining 80 patients, six received the hepatitis B vaccine. Three patients had antibodies to both hepatitis B surface antigen (anti-HBs) and hepatitis B core protein (anti-HBc) with normal aminotransferase levels, and one patient had positive anti-hepatitis C virus (HCV) antibodies, negative HCV RNA, and normal aminotransferase levels. Except for the patients with chronic HBV infection, no significant changes in hepatic function were detected. Conclusions: Patients with Crohn's disease who are candidates for infliximab therapy should be tested for hepatitis B serological markers before treatment and considered for prophylaxis of reactivation using antiviral therapy if positive.

Absence of BK viremia clearance after low-dose cidofovir therapy in kidney transplant recipients with BK virus associated nephropathy

Background: BK virus associated nephropathy occurs in 1-10% of kidney transplant recipients and may be a cause of graft loss. This infection is difficult to manage because of the absence of specific therapy. Cidofovir, a DNA polymerase inhibitor approved for the treatment of CMV retinitis, has shown in vitro activity against BK virus and some clinical efficacy when used at low-dose in uncontrolled series. Objective: To assess the efficacy of low-dose Cidofovir in the treatment of BK virus associated nephropathy. Method: Two adult kidney transplant recipients with biopsy-proven BK nephropathy and persistent high viremia (>10,000 copies/ml) despite 3-month reduction of immunosuppressive therapy were treated by Cidofovir 0.5 mg/kg fortnightly for a total of 16 weeks (8 doses). Clinical response was assessed by following BK viremia. Results: No decrease in BK viremia was observed at any point during cidofovir therapy (see figure). Creatinine clearance remained stable during therapy and no side-effects of Cidofovir were observed. Conclusions: Low-dose Cidofovir therapy was not associated with a clearance or with a significant decrease of BK viremia. This pilot study does not confirm previous reports suggesting clinical efficacy of Cidofovir for BK virus associated nephropathy.

Optimization and regeneration kinetics of lymphatic-specific photodynamic therapy in the mouse dermis.

Lymphatic vessels transport fluid, antigens, and immune cells to the lymph nodes to orchestrate adaptive immunity and maintain peripheral tolerance. Lymphangiogenesis has been associated with inflammation, cancer metastasis, autoimmunity, tolerance and transplant rejection, and thus, targeted lymphatic ablation is a potential therapeutic strategy for treating or preventing such events. Here we define conditions that lead to specific and local closure of the lymphatic vasculature using photodynamic therapy (PDT). Lymphatic-specific PDT was performed by irradiation of the photosensitizer verteporfin that effectively accumulates within collecting lymphatic vessels after local intradermal injection. We found that anti-lymphatic PDT induced necrosis of endothelial cells and pericytes, which preceded the functional occlusion of lymphatic collectors. This was specific to lymphatic vessels at low verteporfin dose, while higher doses also affected local blood vessels. In contrast, light dose (fluence) did not affect blood vessel perfusion, but did affect regeneration time of occluded lymphatic vessels. Lymphatic vessels eventually regenerated by recanalization of blocked collectors, with a characteristic hyperplasia of peri-lymphatic smooth muscle cells. The restoration of lymphatic function occurred with minimal remodeling of non-lymphatic tissue. Thus, anti-lymphatic PDT allows control of lymphatic ablation and regeneration by alteration of light fluence and photosensitizer dose.