Comparison of peginterferon pharmacokinetic and pharmacodynamic profiles.

The pharmacokinetics and in dosing regimens of the currently available pegylated interferon (peginterferon) alfa molecules differ greatly, depending on the size and nature of their polyethylene glycol (PEG) moiety. Peginterferon alfa-2a has a branched 40 kDa PEG chain covalently attached to lysine residues and circulates as an intact molecule. On the other hand, peginterferon alfa-2b has a linear 12 kDa PEG chain covalently attached to interferon-a-2b via an unstable urethane bond that is hydrolysed after injection, releasing native interferon alfa-2b. The difference in pegylation between the two peginterferons has a significant impact on their pharmacokinetic properties. Data from comparative and non-comparative studies indicate that peginterferon alfa-2b has a shorter half-life in serum than peginterferon alfa-2a, and a significant proportion of patients receiving peginterferon alfa-2b may have trough concentrations below the limit of detection during the latter part of the 7-day dosing schedule. However, the pharmacodynamic parameters of the two drugs appear to be similar.

Pharmacodynamics of peginterferon alpha-2a and peginterferon alpha-2b in interferon-naïve patients with chronic hepatitis C: a randomized, controlled study.

BACKGROUND: Peginterferon alpha-2a and alpha-2b, the two commercially available pegylated interferons, have different pharmacokinetic properties that produce differing abilities to suppress replication of the hepatitis C virus. AIM: To compare the pharmacodynamics of peginterferon alpha-2a and peginterferon alpha-2b in interferon-naive patients with chronic hepatitis C. METHODS: Patients were randomized to receive peginterferon alpha-2a, 180 microg (n = 10) or peginterferon alpha-2b 1.0 microg/kg (n = 12) once weekly. The enzymatic activity of 2'5'-oligoadenylate synthetase and levels of neopterin and beta(2)-microglobulin were measured at baseline and at 24, 48, 120 and 168 h. RESULTS: Oligoadenylate synthetase activity and serum neopterin and beta(2)-microglobulin concentrations did not differ significantly between the two patient groups at any time point, nor was there a significant correlation between the serum area under the concentration-time curve of either peginterferon and the area under the concentration-time curve for 2',5'-oligoadenylate synthetase, neopterin and beta(2)-microglobulin. The area under the concentration-time curves calculated for these three markers did not correlate with body mass index stratified at <25 and >or=25 kg/m(2) for either peginterferon. CONCLUSIONS: Despite pharmacokinetic differences between peginterferon alpha-2a and peginterferon alpha-2b, the pharmacodynamic profiles of the two formulations appear to be comparable.

Hepatotoxicity and antiretroviral therapy with protease inhibitors: A review.

Highly active antiretroviral therapy including protease inhibitors has led to dramatic decrease in the morbidity and mortality resulting from infection with human immunodeficiency virus-1. However, this combination regimen can be associated with the occurrence of serious toxicities, which may reduce patient compliance. In particular, human immunodeficiency virus-1 protease inhibitors and nevirapine among nonnucleoside reverse transcriptase inhibitors, have the potential for producing hepatotoxicity. We summarise current knowledge of the hepatotoxic effects associated with the commercially available human immunodeficiency virus-1 protease inhibitors based on a literature review of the major retrospective and prospective clinical studies designed to elucidate risk factors for developing hepatotoxicity among human immunodeficiency virus-1-infected patients receiving antiretroviral therapy containing protease inhibitors. Coinfection with chronic hepatitis, a common occurrence in human immunodeficiency virus-1-infected patients, is identified as an independent risk factor for developing hepatotoxicity in antiretroviral-treated human immunodeficiency virus-1-infected patients treated with antiretroviral regimens containing protease inhibitors. The importance of other risk factors for developing protease inhibitor-associated hepatotoxicity and the mechanism underlying the drug-related hepatotoxicity are discussed. The data indicate that the potential for producing hepatotoxicity is variable among the protease inhibitors and suggest that based on differences in drug-related hepatotoxicity, certain protease inhibitors may be preferred for the treatment of human immunodeficiency virus-hepatitis C virus coinfected patients.

The current role of abdominal ultrasound in the clinical management of patients with AIDS.

Patients with AIDS present a wide variety of clinical manifestations through involvement of various organs. Ultrasonography (US) is easy to perform, safe, inexpensive, not invasive and repeatable. Those features are crucial for AIDS patients, who in industrialised countries are now mostly seen on an outpatient basis thanks to the introduction of Highly Active Antiretroviral Therapy. US can investigate most of the organs affected in AIDS and can guide biopsies, allowing the cyto-histological and microbiological investigations needed for a definitive diagnosis. This paper reviews the wide variety of applications of abdominal US and stresses its importance in the management of a complex and changing condition, particularly in settings where other more expensive imaging techniques are not--and will not be for a long time--available. The increasing use of portable/hand-carried scanners further adds to the value of the technique in such settings. With new treatments, prevalence and morbidity/mortality rates change, but new conditions and new side effects appear. US applications to these new conditions are discussed as well.

[Overview of therapeutic options for cystic echinococcosis]. / Attualità in tema di terapia dell'echinoccocosi cistica.

Surgical excision of echinococcal cyst has long been considered the only effective treatment for echinococcosis. However, the remarkable advances in imaging techniques, particularly ultrasound, made during the past 25 years have greatly facilitated diagnosis, treatment and follow-up. Today, chemotherapy and percutaneous treatments have become widely available. A major step forward in management of the disease came in 2001, when the WHO International Working Group on Echinococcosis (WHO-IWGE) came to a consensus by developing a standardized classification of ultrasound images in cystic echinococcosis. Thus, the most appropriate treatment for patients affected by this serious and sometimes life-threatening disease may now be chosen. An overview of the three main therapeutic options for abdominal- and particularly hepatic-cystic echinococcosis is presented, with focus on the indications and contraindications of each one. Data from long-term follow-up studies are also discussed, with emphasis on the resulting stage-specific criteria for treatment.

Synthesis of a new class of 2,3-dihydro-2-oxo-1H-benzimidazole-1-carboxylic acid derivatives as highly potent 5-HT3 receptor antagonists.

A series of 2,3-dihydro-2-oxo-1H-benzimidazole-1-carboxylic acid esters and amides containing a basic azacyclo- or azabicycloalkyl moiety has been synthesized and evaluated for 5-HT3 antagonistic activity in a radioligand binding assay ([3H]ICS 205930) and in the 5-HT-induced von Bezold-Jarisch reflex in the rat. It was found that endo-substituted azabicycloalkyl derivatives (e.g. 7a, 12a, 12b) were much more active than the corresponding exo analogues (e.g. 7b, 12h, 12i) or azacycloalkyl compounds. Amidic derivatives 12a, 12b, 12c, 12e, 13b, and 13c proved to be about 10 times more active than the corresponding ester derivatives 7a, 11a, 7c, 7d, 8a, and 8b. In particular, compound 12a (DA 6215) showed a Ki = 3.8 nM in the binding test and an ED50 = 1 nM/kg iv in the von Bezold-Jarisch reflex assay, an activity comparable to that of the reference compound 2 (ICS 205930, Ki = 2 nM, ED50 = 2.1 nM/kg). IR spectroscopy studies in the solid state and in CHCl3 solution revealed the existence of an intramolecular hydrogen bond in 13b, taken as a model compound for this class of substances. A molecular modeling study showed that 12a, in its internal hydrogen-bound conformation, well matches a recently proposed pharmacophoric model for 5-HT3 antagonist activity.