Pancreatic toxic effects associated with co-administration of didanosine and tenofovir in HIV-infected adults

The rise in didanosine concentrations in plasma when given with tenofovir raises concern for a high risk of toxic effects. Recommendations to reduce didanosine dose have been issued, but only for adults weighing more than 60 kg. We reviewed cases of pancreatitis in patients receiving didanosine plus tenofovir, didanosine alone, and tenofovir alone to assess the incidence of and risk factors for pancreatitis. Between Aug 1, 2001, and Nov 30, 2003, five of 185 (2.7%) patients receiving didanosine plus tenofovir, one of 182 (0.5%) on didanosine without tenofovir, and none of 208 on tenofovir without didanosine developed pancreatitis (p=0.016). Co-administration of both drugs versus each of them individually was an independent risk factor for pancreatitis (crude hazard ratio 10.666, 95% CI 1.246-91.294, p=0.031). These results suggest that the risk of pancreatitis is heightened when didanosine and tenofovir are given together.

Lack of neurotoxicity of the vascular targeting agent ZD6126 following repeated i.v. dosing in the rat

The vascular targeting agent ZD6126 is a water-soluble prodrug of N-acetylcolchinol that acts by disrupting the cytoskeleton of tumor endothelial cells. It is currently undergoing clinical evaluation in man. As peripheral neuropathy is a major dose-limiting toxicity associated with tubulin binding agents, the neurotoxic potential of ZD6126 was investigated in male and female Wistar rats. ZD6126 was administered i.v. at up to maximum tolerated doses using subacute (0 to 20 mg/kg/d for 5 days) and chronic (0 to 10 mg/kg/d for 5 days, repeated monthly for 6 months) dosing regimens. A separate study examined a combination of ZD6126 (three cycles of ZD6126 given as in the chronic dosing regimen) and paclitaxel (12 mg/kg/wk for 9 weeks) to assess whether coadministration of ZD6126 altered the time course or magnitude of a paclitaxel-induced neuropathy. Neurotoxic potential was examined using a comprehensive series of tests including a functional observation battery, measurements of muscle strength (forelimb and hind limb grip strength), nociception (tail flick test), locomotor activity, neuropathology, and whole nerve electrophysiology. There was no evidence that ZD6126 induced neurotoxicity in the rat following either subacute or chronic i.v. dosing. In a chronic electrophysiology study, ZD6126 produced a slight slowing of the maturational increase of caudal nerve amplitude, with some evidence of reversibility. However, this was not associated with any changes in caudal nerve conduction velocity, motor nerve conduction velocity or amplitude, functional observation battery behavioral and function parameters (including no effects on tail flick latency), and neuropathology. As expected, paclitaxel administration was associated with a significant decrease in caudal nerve conduction velocity (P = 0.0001). Coadministration of ZD6126 did not increase the neurotoxicity of paclitaxel. These studies suggest that ZD6126 should not induce the peripheral neuropathy associated with other antitubulin chemotherapeutic agents and that ZD6126 may not exacerbate the neurotoxicity of other agents with dose-limiting neuropathies.

Oral activity of ether lipid ester prodrugs of cidofovir against experimental human cytomegalovirus infection

Infection with human cytomegalovirus (HCMV) can cause serious complications in bone-marrow and solid-organ transplant recipients, and current therapies are not optimal. We evaluated 2 orally active ether lipid ester analogues of cidofovir (CDV)--hexadecyloxypropyl-CDV (HDP-CDV) and octadecyloxyethyl-CVD (ODE-CDV)--in severe combined immunodeficient mice in which either human fetal retinal tissue or human fetal thymus and liver tissue had been implanted and was later infected with HCMV. Our results indicate that orally administered treatment with either HDP-CDV or ODE-CDV is 4-8-fold more active, on a molar basis, than is intraperitoneally administered CDV. These data suggest that HDP-CDV and ODE-CDV should be further evaluated as potential antiviral agents for treatment of HCMV infection.

Comparison of susceptibility of pest Euschistus servus and predator Podisus maculiventris (Heteroptera: Pentatomidae) to selected insecticides

Susceptibility of the brown stink bug, Euschistus serous (Say), and the spined soldier bug, Podisus maculiventris (Say), to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam, was compared in residual and oral toxicity tests. Generally, susceptibility of P. maculiventris to insecticides was significantly greater than or not significantly different from that of E. servus. Cyfluthrin and oxamyl were more toxic to the predator than to E. servus in residual and feeding tests, respectively. Dicrotophos is the only compound that exhibited both good residual and oral activity against E. servus, but even this toxicant was more toxic to the predator than to the pest in oral toxicity tests. Feeding on indoxacarb-treated food caused high mortality for both nymphs and adults of P. maculiventris. In contrast, E. servus was unaffected by feeding on food treated with this compound. Insecticide selectivity to P. maculiventris was detected only with acetamiprid for adults in residual toxicity tests and for nymphs in oral toxicity tests. Because insecticide selectivity to P. maculiventris was limited, it is extremely important to conserve P. maculiventris in cotton fields by applying these insecticides for control of brown stink bugs only when the pest reaches economic threshold.

Preliminary study on pharmacokinetics of dacarbazine and fotemustine in glioblastoma multiforme patients does not indicate gender-specific differences

Twelve patients (six female and six male) with histologically proven glioblastoma multiforme were investigated during the administration of the first cycle of dacarbazine (D; 200 mg/m) and fotemustine (F; 100 mg/m). In total, 18 blood samples were collected for pharmacokinetic analysis (maximum plasma concentration, area under the concentration-time curve and total clearance) of D and F at 14 time points during therapy. D, its metabolite 5-aminoimidazole-4-carboxamide and F were evaluated by reversed-phase HPLC. For statistical calculations, groups were compared by the non-parametric Wilcoxon test. p<0.05 was considered statistically significant. No significant gender-dependent differences were observed in the pharmacokinetics of D and F. An additional response re-evaluation of 100 patients (50 female and 50 male) with glioblastoma multiforme, treated at our institution with D and F, gave no hint of any gender-dependent different response rates. We conclude that there is no evidence, neither from pharmacokinetic nor from our clinical data, to consider different dosages of D and F in female and male patients with glioblastoma multiforme.

Antiviral prophylaxis of smallpox

Proof-of-concept studies suggest that current defences against smallpox could be strengthened by supplementing vaccination with antiviral drug prophylaxis, based on aerosolized or orally available forms of the long-acting medication cidofovir. Delivery of aerosolized cidofovir to mice results in its prolonged retention in respiratory tissues and protection against lethal intranasal or aerosol poxviral challenge. Although cidofovir itself is not orally available, the addition of an alkoxyalkanol ether side-chain allows it to be absorbed from the gastrointestinal tract. This also markedly increases its antiviral activity and lengthens its intracellular half-life from roughly 3 to 8-10 days. Oral treatment also protected mice against lethal poxviral challenge. These results suggest that a single aerosol dose of cidofovir (or an alkoxyalkanol-ether derivative) could provide prolonged protection against initiation of smallpox infection, whereas oral treatment could prevent both initiation of infection and internal dissemination of virus. Both approaches may avoid the nephrotoxicity that occasionally results from intravenous cidofovir therapy.

[Therapy of malignant melanoma at the stage of distant metastasis]

Treatment of melanoma in the stage of distant metastasis aims on palliation and achievement of durable tumor remission with prolongation of survival. As long as metastasis is confined to one organ system and is removable, surgery remains the treatment of first choice. In limited metastasis radiotherapy may likewise be indicated, particularly in bone and brain metastasis. More extensive metastasis should be treated by chemotherapy or chemoimmunotherapy. Monochemotherapy with dacarbazine, temozolomide, fotemustine and vindesine or its combinations with interferon-alpha are currently preferred. Polychemotherapy or its combinations with interferon-alpha and interleukin-2 are suitable to produce higher response rates but failed to prolong survival. As these treatments are associated with substantially higher toxicity they have been widely abandoned. Combined treatment with dacarbazine and interferon-alpha obtain tumor responses or stable disease in 40-50% and objective tumor remissions in 15-20% of patients. Effective cancer vaccination strategies and blockade of melanoma specific target molecules are currently developed as new treatment options.

Intracoronary versus intravenous injection of 99mTc-tetrofosmin: comparison of myocardial perfusion patterns and wall motion

OBJECTIVES

The accuracy of viability and defect size detection by Tc-tetrofosmin has been discussed by several authors. The lower myocardial extraction fraction of the latter compared with Tc-sestamibi or Tl has often been emphasized. We hypothesized that the intracoronary (i.c.) injection of tracer activity, i.e. higher than that theoretically achievable in the case of intravenous (i.v.) administration, could demonstrate the clinical relevance of this finding intra-individually. In this study, myocardial perfusion images obtained after tracer injection down the infarct-related artery were compared with i.v. injection images in the same patients. The trial also provided us with the opportunity to compare the wall motion values calculated using conventional Tc-tetrofosmin gated single-photon emission computed tomography (SPECT) studies with those obtained using optimal target/background ratios after i.c. injection.

METHODS

Fourteen patients with acute myocardial infarction, no history of previous cardiac events, single vessel disease and no visible collaterals in the coronary arteriogram were included in the study. Electrocardiogram gated SPECT was carried out separately after i.c. and i.v. injections of the tracer within 5-7 days following thrombolytic therapy. Myocardial perfusion patterns were compared by contingency table analysis after semi-quantitative visual scoring. Segmental wall motion was compared using quantified polar map data in a subset of patients (eight of 14) with normal to moderately hypoperfused myocardium supplied by the left coronary artery.

RESULTS

Visual perfusion scores of both studies showed good concordance (kappa, 0.70), with complete agreement in 94 of 119 segments. Nearly all of the discordant segments (24 of 25) were mildly better scored in i.c. studies than in i.v. studies. The mean wall motion values calculated on polar maps of 78 segments for i.c. and i.v. studies were 8.4 +/- 1.2 mm and 8.2 +/- 1.3 mm (mean Delta wall motion=0.23 mm), respectively. High segmental wall motion correlation was observed (R=0.90; P<0.0001).

CONCLUSION

It can be concluded that infarct-related myocardial perfusion scores obtained after i.c. and i.v. injections of Tc-tetrofosmin compare favourably, with a total agreement rate of 79%. However, the additional information obtained in 21% of the total number of myocardial segments by i.c. injection may indicate a mild underestimation of myocardial viability by i.v. injection. Conventional gated SPECT using i.v. Tc-tetrofosmin was demonstrated to be a reliable technique in the detection of true wall motion.

Biological effects of short-term or prolonged administration of 9-[2-(phosphonomethoxy)propyl]adenine (tenofovir) to newborn and infant rhesus macaques

The reverse transcriptase inhibitor 9-[2-(phosphonomethoxy)propyl]adenine (PMPA; tenofovir) was previously found to offer strong prophylactic and therapeutic benefits in an infant macaque model of pediatric human immunodeficiency virus (HIV) infection. We now summarize the toxicity and safety of PMPA in these studies. When a range of PMPA doses (4 to 30 mg/kg of body weight administered subcutaneously once daily) was administered to 39 infant macaques for a short period of time (range, 1 day to 12 weeks), no adverse effects on their health or growth were observed; this included a subset of 12 animals which were monitored for more than 2 years. In contrast, daily administration of a high dose of PMPA (30 mg/kg subcutaneously) for prolonged periods of time (>8 to 21 months) to 13 animals resulted in a Fanconi-like syndrome (proximal renal tubular disorder) with glucosuria, aminoaciduria, hypophosphatemia, growth restriction, bone pathology (osteomalacia), and reduced clearance of PMPA. The adverse effects were reversible or were alleviated following either complete withdrawal of PMPA treatment or reduction of the daily regimen from 30 mg/kg to 2.5 to 10 mg/kg subcutaneously. Finally, to evaluate the safety of a prolonged low-dose treatment regimen, two newborn macaques were started on a 10-mg/kg/day subcutaneous regimen; these animals are healthy and have normal bone density and growth after 5 years of daily treatment. In conclusion, our findings suggest that chronic daily administration of a high dose of PMPA results in adverse effects on kidney and bone, while short-term administration of relatively high doses and prolonged low-dose administration are safe.

Traitement par cidofovir topique d’infections cutanées à papillomavirus humain, poxvirus et Herpes simplex virus chez des malades séropositifs pour le VIH

INTRODUCTION

Cidofovir (Vistide) is an antiviral marketed for the treatment of cytomegalovirus retinitis. Clinical efficacy has been reported with its broad antiviral spectrum that includes poxvirus, human papilloma virus and Herpes simplex. In immunodepressed patients, these infectious dermatoses are often recurrent and resistant. In an open study, we assessed the efficacy and clinical tolerance of cidofovir gel at 1 p. 100.

PATIENTS AND METHODS

Twelve HIV-infected adults were included. Cidofovir gel at 1 p. 100 was applied directly on the lesions, once a day, for two weeks on the molluscum and condylomas, four weeks on the warts and one week on the chronic herpes.

RESULTS

Four patients presented with warts and 3 of them with verruca plana. In 2 of the verruca plana patients, regression was complete although relapse was observed. Two failures were noted. Local application of the gel was not tolerated by one patient suffering from condylomas of the penis. Four patients presented with molluscum contagiosum. Two complete regressions with strong local reaction and two partial regressions were observed. The latter two patients exhibited severe immunodepression, one of them subsequently received infusions of cidofovir. Two women suffering from vulvar and perianal herpes resistant to acyclovir were treated for one week with cidofovir gel at 1 p. 100: no response was obtained. One of the patients stopped treatment because of local intolerance. A third, less immunodepressed, woman responded partially.

COMMENTS

In HIV-positive patients, cidofovir in topical form appears to be indicated in extensive and confluent molluscum contagiosum. However, the effect occurs at the cost of local inflammation. The results are disappointing in papillomavirus lesions and in chronic acyclovir-resistant herpes ulcerations, efficacy is debatable.

Atazanavir (Reyataz): new recommendations if combined with tenofovir (Viread) -- and warning on Viagra, Cialis, and Levitra

The FDA published new information on drug interactions that patients taking Reyataz should know.

The management of oral human papillomavirus with topical cidofovir: a case report

Cidofovir, a purine nucleotide analog of cytosine, has showed significant promise against a number of DNA viruses. In 1997, the US Food and Drug Administration approved the use of cidofovir intravenously in the treatment of cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome. Recent studies and reports suggest that a topical form of cidofovir may be useful for treating viral cutaneous lesions recalcitrant to traditional treatments. We report the case of a 36-year-old man with human immunodeficiency virus (HIV) and recalcitrant human papillomavirus (HPV) lesions on the gingiva that were successfully treated with cidofovir gel 1%.

Tenofovir disoproxil fumarate for the treatment of lamivudine-resistant hepatitis B

BACKGROUND & AIMS

Lamivudine resistance occurs in patients with chronic hepatitis B at rates of 16%-32% after 1 year and 49% after 3 years. Adefovir dipivoxil, a nucleotide analogue recently approved by the Food and Drug Administration for the treatment of chronic hepatitis B, is effective against hepatitis B virus (HBV) but has been associated with renal toxicity at high doses. Tenofovir disoproxil fumarate is another nucleotide analogue with demonstrated antiviral activity against both wild-type and lamivudine-resistant HBV. Tenofovir, at its licensed dose, has not been associated with renal dysfunction.

METHODS

We describe a series of 9 patients with lamivudine-resistant hepatitis B treated with tenofovir, 300 mg, once daily before the availability of adefovir. Levels of HBV DNA, alanine aminotransferase (ALT), hepatitis B e antigen (HBeAg), and antibody to HBeAg (anti-HBe) were monitored.

RESULTS

The addition of tenofovir to the existing regimen of lamivudine resulted in a median decline of 4.5 log(10) copies/mL in HBV DNA levels (range, 3.2-6.3 log(10) copies/mL) after a median treatment duration of 12 months (range, 6-16 mo). HBeAg seroconversion was observed in 2 patients, with a third patient undergoing HBeAg loss while remaining anti-HBe negative. In 4 of 7 patients with elevated ALT levels at baseline, ALT levels normalized. No significant adverse events were encountered during treatment.

CONCLUSIONS

In patients with lamivudine-resistant hepatitis B, treatment with tenofovir is well tolerated and results in significant virological, serological, and biochemical improvements on par with those seen with high-dose adefovir (30 mg/day) therapy, without the complication of renal toxicity.

Management of chronic hepatitis B in the HIV-infected patient

Coinfection with HIV and hepatitis B virus (HBV) is common because of their shared modes of transmission. HIV infection alters the natural history of HBV infection, leading to more severe liver disease, decreased hepatitis B e antigen seroconversion, and higher HBV DNA levels. Furthermore, end-stage liver disease has emerged as a common cause of morbidity and mortality in HIV-infected persons receiving HAART. For these reasons, it is important to vaccinate susceptible persons against HBV infection and to diagnose and treat chronic hepatitis B in HIV-infected persons. The treatment plan for chronic hepatitis B needs to be individualized based on the stage of both viral infections and the available options. It is anticipated that we are entering a period of combination therapy for chronic hepatitis B, but the ideal combination needs to be elucidated.

Single dose of the antivascular agent, ZD6126 (N-acetylcolchinol-O-phosphate), reduces perfusion for at least 96 hours in the GH3 prolactinoma rat tumor model

Tumor vasculature is an attractive therapeutic target as it differs structurally from normal vasculature, and the destruction of a single vessel can lead to the death of many tumor cells. The effects of antivascular drugs are frequently short term, with regrowth beginning less than 24 hours posttreatment. This study investigated the duration of the response to the vascular targeting agent, ZD6126, of the GH3 prolactinoma, in which efficacy and dose-response have previously been demonstrated. GH3 prolactinomas were grown in the flanks of eight Wistar Furth rats. All animals were treated with 50 mg/kg ZD6126. The tumors were examined with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) 24 hours pretreatment and posttreatment, and at a single time between 48 and 96 hours posttreatment. No evidence of recovery of perfusion was observed even at the longest (96-hour) time point. Involvement of a statistician at the project planning stage and the use of DCE-MRI, which permits noninvasive quantitation of parameters related to blood flow in intact animals, allowed this highly significant result to be obtained using only eight rats.

Intralesional cidofovir and surgical excision for laryngeal papillomatosis

OBJECTIVE

To evaluate the efficacy of cidofovir intralesional therapy in recurrent respiratory papillomatosis and the role of surgical excision as an associated treatment.

STUDY DESIGN

Prospective study and case series.

METHOD

Twenty-six patients received intralesional cidofovir. Three endoscopies were performed at monthly intervals, with intralesion injections of cidofovir at 5 mg/mL. Further endoscopic evaluation was made at 3 or 6 months depending on whether there was persistent papillomatosis. Cidofovir was again injected in the case of persistent papillomas, and treatment was repeated as long as papillomas were observed. Surgical excision of the papilloma was only performed in cases of airway obstruction or in cases proving resistant to cidofovir.

RESULTS

Complete remission was obtained in 8 (31%) patients after an average of 2.6 endoscopic treatment. Seventeen (65%) patients presented slight or mild disease at endpoint (final severity score 1-4). Significant results were obtained in both adults and children. A greater response was obtained in the supraglottis and glottis subsites than in subglottis, tracheal, and other sites. Patients conforming to the 1 month interinjection schedule showed better responses in supraglottis subsite than those receiving their injections with intervals longer than 1 month. Combined therapy (cidofovir plus excision) was necessary in persistent papillomas. No patients presented with any systemic or local side effects.

CONCLUSIONS

Cidofovir therapy was an effective treatment in adults and in children, allowing papillomatosis to be controlled without observed side effects. Surgical excision associated with cidofovir injections remained necessary in persistent papillomatosis after cidofovir treatment.

Emtricitabine/Tenofovir Disoproxil Fumarate

The nucleoside analogue reverse transcriptase inhibitor (RTI) emtricitabine and the nucleotide analogue RTI tenofovir disoproxil fumarate (tenofovir DF) have each shown antiviral activity against a number of HIV clinical isolates and cell lines. HIV variants with reduced susceptibility to emtricitabine and tenofovir have been selected for in vitro and have also been isolated from patients receiving the agents. Low rates of these variants have been observed in patients experiencing virological failure in large studies of emtricitabine- or tenofovir DF-containing therapy. Co-formulated oral emtricitabine/tenofovir DF was bioequivalent to the two agents as separate formulations in a pharmacokinetic trial in healthy volunteers. There are no published data on the clinical antiviral efficacy of co-formulated oral emtricitabine/tenofovir DF. However, each agent is effective in combination regimens with other drugs. Ongoing studies in antiretroviral-naive patients are evaluating the efficacy of the individual formulations given together in combination with efavirenz or lopinavir/ritonavir. In the latter trial, HIV RNA levels were reduced and CD4+ cell counts were increased at 24 and 48 weeks. Emtricitabine and tenofovir DF are generally well tolerated. Diarrhoea, nausea and vomiting were the most common adverse events reported with coadministered emtricitabine and tenofovir DF as separate formulations as part of combination therapy.

Tubulopathy consecutive to tenofovir-containing antiretroviral therapy in two patients infected with human immunodeficiency virus-1

Tenofovir disopril fumarate, a new nucleotide analogue against human immunodeficiency virus-1 (HIV-1), can induce hypophosphataemia, the mechanism of which is unclear. Moreover, a renal tubulopathy can occur in long-term treated patients, as observed in 2 HIV-1-infected patients after 12 months of tenofovir therapy, with polyuria-polydipsia, proteinuria, glycosuria and amino-aciduria, which resolved after discontinuation of tenofovir. The risk of renal tubulopathy symptoms in patients on long-term tenofovir therapy should be noted.

In vivo videomicroscopy reveals differential effects of the vascular-targeting agent ZD6126 and the anti-angiogenic agent ZD6474 on vascular function in a liver metastasis model

Metastases require a functional blood supply for progressive growth. Thus, therapies that target metastatic vasculature have potential clinical utility. The effects of the vascular-targeting agent (VTA), ZD6126, and the anti-angiogenic agent, ZD6474, on vascular development and function within metastases were compared in an experimental liver metastasis model. Ras-transformed PAP2 fibroblasts were injected into the mesenteric veins of SCID mice to produce a control liver metastasis burden of approximately 40% at 14 days. Mice given a single dose of ZD6126 (200 mg/kg, i.p.) on day 13 were examined 24 h later. Histology revealed a significant reduction in metastatic burden, associated with extensive tumor necrosis, increased tumor cell apoptosis and a reduction in tumor-associated vasculature. In vivo videomicroscopy (IVVM) revealed disrupted, non-functional vascular channels within metastases, with no blood flow. Mice given ZD6474 on days 4 to 10 (50 mg/kg daily, oral gavage) were examined on day 11. Histology revealed a lower metastatic burden, significant reductions in metastasis size and vasculature, and a significant increase in tumor cell apoptosis. IVVM revealed extensive reductions in vascularity and blood flow within metastases. Neither ZD6126 nor ZD6474 treatment affected surrounding normal liver tissue. This study shows that both agents can reduce experimental liver metastasis with no apparent effect on normal vasculature. However, these reductions were attained through distinct effects on the metastatic vasculature. Understanding differences in the modes of action of VTAs and anti-angiogenic agents will be important in optimizing their clinical application and in developing appropriate combination strategies.

Tenofovir Disoproxil Fumarate

Tenofovir disoproxil fumarate (tenofovir DF) is an oral prodrug of tenofovir, a nucleotide (nucleoside monophosphate) analogue with activity against retroviruses, including HIV-1, HIV-2 and hepadnaviruses. Following absorption, tenofovir DF is rapidly converted to tenofovir, which is metabolised intracellularly to its active anabolite tenofovir diphosphate, which is a competitive inhibitor of HIV-1 reverse transcriptase and terminates the growing DNA chain. Tenofovir exerts antiviral effects in a variety of cell types, including resting cells. Tenofovir exhibits longer serum (17 hours) and intracellular (> or =60 hours) half-lives than those of nucleoside analogues, which supports a flexible once-daily administration schedule. The pharmacokinetics of tenofovir are dose-proportional and similar in healthy volunteers and HIV-infected individuals. The oral bioavailability of tenofovir is enhanced by administration with a high-fat meal, but is similar at steady state when administered with or without a typical meal. Tenofovir is not a substrate, inducer or inhibitor of human cytochrome P450 enzymes in vitro or in vivo. Tenofovir DF has been studied with 15 other antiretroviral and other concomitant medications frequently used in the HIV-1-infected population. With the exception of didanosine and atazanavir, which require dosage modifications, no clinically significant drug interactions have been observed with tenofovir DF. The recommended oral dosage of tenofovir DF in adults is 300 mg/day. Tenofovir is eliminated by renal elimination, including tubular secretion; dose-interval adjustments are necessary for tenofovir DF in patients with significant renal impairment. No dosage adjustment of tenofovir DF is necessary in patients with liver disease.

Retrospective evaluation of bone pain palliation after samarium-153-EDTMP therapy

PURPOSE: The aim of this study was to evaluate the degree of metastatic bone pain palliation and medullar toxicity associated with samarium-153-EDTMP treatment. METHODS: Seventy-three patients with metastatic bone pain having previously undergone therapy with samarium-153-EDTMP (1 mCi/kg) were retrospectively evaluated. Routine follow-up included pain evaluation and blood counts for 2 months after treatment. Pain was evaluated using a subjective scale (from 0 to 10) before and for 8 weeks after the treatment. Blood counts were obtained before treatment and once a week for 2 months during follow-up. Dosimetry, based upon the urinary excretion of the isotope, was estimated in 41 individuals, and the resulting radiation absorbed doses were correlated with hematological data. RESULTS: Reduction in pain scores of 75% to 100% was obtained in 36 patients (49%), with a decrease of 50% to 75%, 25% to 50%, and 0% to 25% in, respectively, 20 (27%), 10 (14%), and 7 (10%) patients. There was no significant relationship between the pain response and location of the primary tumor (breast or prostate cancer). Mild to moderate myelosuppression was noted in 75.3% of patients, usually with hematological recovery at 8 weeks. The mean bone marrow dose was 347 ± 65 cGy, and only a weak correlation was found between absorbed dose and myelosuppression (Pearson coefficient = .4). CONCLUSIONS: Samarium-153-EDTMP is a valuable method for metastatic bone pain palliation. A mild to moderate and transitory myelosuppression is the main toxicity observed after samarium therapy, showing a weak correlation with dosimetric measures.

Effects of the GABAB receptor agonists baclofen and 3-aminopropylphosphinic acid (3-APA) on food intake in rats

It has previously been demonstrated that central administration of the GABAB agonist baclofen increases food intake in non-deprived or satiated animals by action at the central GABAB receptors. It has also been shown that systemic administration of baclofen increases food intake in non-deprived rats. Although baclofen crosses the blood brain barrier from systemic circulation to enter the brain, it is conceivable that it may increase food intake by a peripheral mode of action. This possibility was examined in the present study. The effects of intraperitoneal (i.p.) administration of the GABAB receptor agonists baclofen and 3-aminopropylphosphinic acid (3-APA) were investigated on food intake in non-deprived rats. 3-APA is a potent GABAB agonist that does not penetrate the blood brain barrier. The results show that while baclofen (1-4 mg/kg) increases food intake in a dose-related manner, 3-APA (0.5-2 mg/kg) has no effects on food consumption. The results indicate that a peripheral GABAB mechanism is not involved in the hyperphagia elicited by systemic administration of baclofen and suggests that the drug increases food intake by a central mode of action.

The cotton rat model for adenovirus ocular infection: antiviral activity of cidofovir

To determine the antiviral effects of compounds against ocular adenovirus (AdV) infection, we established an animal model of AdV infection in cotton rat eyes. Cotton rat eyes were inoculated intrastromally and topically with four AdV serotypes 4, 5, 8, and 37, and treated topically with 1% HPMPC (cidofovir) eye drops twice a day. The infected corneas were extracted and homogenized, and virus titers in the cornea specimens were determined by a plaque assay. The virus titer in AdV type 5-inoculated eyes peaked on days 0 through 3 after inoculation and virus shedding was detected for 18.0+/-2.8 days. AdV 5 antigen in the infected corneas was demonstrated in the corneal epithelial cells by immunofluorescence stain. However, for AdV serotypes 4, 8, and 37, no evidence of continued virus replication in cotton rat eyes was noted. Specimens from cidofovir-treated eyes infected with AdV 5 demonstrated a statistically significant reduction in the mean virus titer (days 3-15) (P=0.028) and virus shedding duration (P=0.0014), as compared with those of the control group.

Progressive multifocal leukoencephalopathy successfully treated with highly active antiretroviral therapy and cidofovir in an adolescent infected with perinatal human immunodeficiency virus (HIV)

Progressive multifocal leukoencephalopathy is an infectious demyelinating brain disease caused by the JC virus that is associated with significant morbidity and mortality in the immunocompromised host. We report a case of progressive multifocal leukoencephalopathy successfully treated with highly active antiretroviral therapy and cidofovir in an adolescent patient perinatally infected with human immunodeficiency virus (HIV).

Tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate (tenofovir DF) is a prodrug of tenofovir, a nucleotide reverse transcriptase inhibitor. In two large, well designed, placebo-controlled clinical trials, tenofovir DF 300 mg/day resulted in significant reductions in HIV-1 RNA from baseline compared with placebo at 24 weeks in antiretroviral-experienced patients with HIV infection. Patients in both treatment groups continued to receive existing stable antiretroviral therapy. In an extension phase of one trial, these reductions in viral load were maintained after 96 weeks of treatment with tenofovir DF. Preliminary data from a large, 3-year comparative trial suggest the clinical efficacy of tenofovir DF in combination with baseline antiretroviral therapy is similar to that of stavudine in antiretroviral-naive patients with HIV infection. Virological substudies showed that viral suppression was maintained in patients who developed new reverse transcriptase mutations during tenofovir DF therapy (in combination with existing stable antiretroviral drugs) for up to 48 weeks. Isolates of HIV infrequently developed the K65R mutation during 96 weeks of tenofovir DF therapy. Tenofovir DF is generally well tolerated. The most commonly observed adverse events seen with tenofovir DF (in combination with other antiretroviral drugs) were predominantly of a gastrointestinal nature.

A case of severe monkeypox virus disease in an American child: emerging infections and changing professional values

Monkeypox virus disease is a rare zoonosis that until recently was limited to Central Africa. We describe the clinical features of the third child in the United States reported with this newly emerging infection. This child was part of a large cluster of individuals in the Midwest infected by prairie dogs that had contracted the virus when housed with infected small mammals imported from Africa. The differential and laboratory diagnoses and the difficulty finding physicians and nurses to care for this patient are discussed.

Inhibition of tetraphenylphosphonium-induced NMR-visible lipid accumulation in human breast cells by chlorpromazine

The effects of chlorpromazine (CPZ) on the lipid accumulation induced by the cationic lipophilic compound tetraphenylphosphonium chloride (TPP) were examined using proton nuclear magnetic resonance spectroscopy (NMR), lipid extraction and thin layer chromatography (TLC), and electron microscopy (EM). Chlorpromazine at concentrations of 12 or 25 microM significantly reduced the NMR-visible lipid accumulation induced by a 48-h treatment with 6.25 microM TPP in the human breast cell line, HBL-100, without affecting cell viability. TPP caused threefold increases in whole-cell triglyceride levels that were attenuated by the addition of CPZ. Electron micrographs of TPP-treated HBL-100 cells showed that the destruction of mitochondria was accompanied by the accumulation of lipid droplets and myelinoid bodies. The addition of CPZ to TPP-treated cells reduced the occurrence of lipid droplets but not of mitochondrial destruction. Treatment with CPZ, in the presence or absence of TPP, resulted in large cytoplasmic inclusions indicating the inhibition of lysosomal metabolism. The induction and attenuation of NMR-visible lipids in conjunction with concomitant changes in both intracellular lipid droplets and whole-cell triglyceride levels provides evidence that NMR-visible lipids arise from cytoplasmic neutral lipid droplets. The observation that CPZ, a known inhibitor of lysosomal and cytosolic lipid metabolism, attenuates the formation of neutral triglycerides indicates that lysosomal processing may be a major step in the accumulation of NMR-visible lipid in breast cell lines.

Multicentric Castleman's disease treated with antivirals and immunosuppressants

A patient negative for human immunodeficiency virus (HIV) developed multicentric Castleman's disease (MCD) and Kaposi's sarcoma (KS) associated with active human herpesvirus 8 (HHV-8) infection. He was treated with sequential antiviral therapy, chemotherapy, and corticosteroids. HHV-8 levels were monitored throughout the course of the patient's illness, and were found to rise on relapse. No consistent change in HHV-8 levels was found with antiviral therapy. We demonstrate that in this patient antiviral therapy was clinically ineffective, and did not alter HHV-8 levels, but that corticosteroid and combination chemotherapy led to clinical improvement. Despite the implication of HHV-8 as a cause of MCD, few studies have correlated HHV-8 levels with clinical response.

[BK virus-associated nephropathy]

BK virus was first detected more than 30 years ago, however its role long time was not exactly defined. The virus is usually acquired in childhood; seroprevalence rate in adults appears to be 60-80%. In most cases the infection is asymptomatic. After renal transplantation it may manifest as so-called BK virus-associated nephropathy by gradual decrease of allograft function or signs of acute rejection. There is no effective therapy of BK virus-associated nephropathy to date. Treatment with low-dose cidofovir is under investigation.

Detection of myocardial contractile reserve by low-dose dobutamine quantitative gated single-photon emission computed tomography in patients with Kawasaki disease and severe coronary artery lesions

We studied 24 patients with severe coronary artery lesions to assess myocardial perfusion and left ventricular contractile reserve simultaneously using low-dose dobutamine quantitative electrocardiographically gated single-photon emission computed tomography in patients with Kawasaki disease. Low-dose dobutamine infusion was started after an injection of technetium-99m tetrofosmin at rest. Myocardial contractile reserve was evaluated using the post-stress and low-dose dobutamine images, and myocardial perfusion was evaluated using the stress and rest images. Quantitative electrocardiographically gated single-photon emission computed tomography during low-dose dobutamine infusion is a useful and safe method for the combined evaluation of myocardial contractile reserve and myocardial perfusion.

A Scheduled Protocol for the Treatment of Juvenile Recurrent Respiratory Papillomatosis With Intralesional Cidofovir

OBJECTIVE

To assess the efficacy of treating juvenile recurrent respiratory papillomas with intralesional cidofovir using a scheduled treatment protocol.

DESIGN

Prospective case series.

SETTING

Tertiary care academic medical center.

PATIENTS

Of 5 pediatric patients with recurrent respiratory papillomas, 2 had severe recurrent papillomatosis requiring long-term therapy of laser ablations every 2 weeks prior to cidofovir treatments. The 3 other patients were newly diagnosed or had milder disease.

INTERVENTION

Intralesional cidofovir (1 mg/kg) was administered during each scheduled visit. The first 4 treatments were at 2-week intervals (week 0, 2, 4, and 6). Subsequent treatment intervals were each increased by 1 week (treatments took place at week 9, 13, 18, 24, etc). Concomitant laser ablation was used only for bulky lesions.

MAIN OUTCOME MEASURES

Papilloma stage and need for laser ablation at each scheduled visit.

RESULTS

The mean follow-up time was 66 weeks. The mean (SD) papilloma stage decreased from 9.2 (5.5) at initial presentation to 3.4 (2.6) within 2 weeks of the first injection (P<.05), and continued to decrease for the remaining of the follow-up period. Papilloma stage 0 was achieved in 4 of the 5 patients. The need for laser ablation of papillomas also decreased within 4 weeks of treatment initiation (P<.05). At 9 weeks, no patient required laser therapy. One patient was removed from the protocol after 58 weeks.

CONCLUSION

An intralesional treatment protocol with cidofovir and increasing intervals between scheduled treatment was successful the long-term management of juvenile respiratory papillomatosis.

Intraläsionale Cidofovir-Injektion bei rezidivierender Larynxpapillomatose - Erste Ergebnisse

BACKGROUND

The treatment of recurrent laryngeal papillomatosis still presents an important therapeutic problem. This primarily benign disease of the larynx is caused by an infection with the human papilloma virus (HPV) and forms epithelial neoplastic papillomas. Therapy in larynx obstructing papillomatosis usually requires laser ablation. Cidofovir acts virustatically as an nucleosidanalogon. Currently pilot studies investigate the effectiveness of intralesional Cidofovir injection.

PATIENTS AND METHODS

The present study covers the period from October 2001 to March 2003. Seven patients, age of five to 70 years, were treated with intralesional injections of Cidofovir after microlaryngoscopic ablation of laryngeal papillomas. In all patients papillomatosis was confirmed histologically and a clinical-phoniatric examination and a photo documentation pre- and postoperatively was carried out. We treated patients to a maximum of six sessions.

RESULTS AND CONCLUSIONS

After three to six sessions of laser ablation of the papillomas and intralesional injections with Cidofovir a distinct papilloma reduction could be observed in all patients and in two cases a complete remission was achieved. The follow-up period of seven to 15 months revealed no recurrent laryngeal papillomatosis. The majority of patients showed a defined voice improvement. There were no local or systemic side-effects caused by the virustatic drug. Intralesional injection of Cidofovir appears to develop into a promising adjuvant therapy option in recurrent laryngeal papillomatosis. First results of the study seem to achieve a considerable reduction of the previously high rate of recurrence of laryngeal papillomatosis.

Successful cidofovir treatment of adenovirus-associated hemorrhagic cystitis and renal dysfunction after allogenic bone marrow transplant

We present a patient who developed hemorrhagic cystitis and renal dysfunction after unrelated bone marrow transplantation. Polyoma BK virus and adenovirus 11 were detected in the urine. Vidarabine was administered without effect. Relatively low dose cidofovir was efficacious. Renal function improved, and the urinary secretion of adenovirus stopped.