A double-blind comparative study of the safety and efficacy of caspofungin versus micafungin in the treatment of candidiasis and aspergillosis.

The safety and efficacy profile of caspofungin and micafungin in Japanese patients with fungal infections were directly compared in this prospective, randomized, double-blind study. The proportion of patients who developed significant drug-related adverse event(s) (defined as a serious drug-related adverse event or a drug-related adverse event leading to study therapy discontinuation) was compared in 120 patients [caspofungin 50 mg, or 50 mg following a 70-mg loading dose on Day 1 (hereinafter, 70/50 mg) group: 60 patients; micafungin 150 mg: 60 patients]. The overall response rate was primarily evaluated in the per-protocol set (PPS) population. The proportion of patients who developed significant drug-related adverse events was 5.0 % (3/60) in the caspofungin group and 10.0 % (6/60) in the micafungin group [95 % confidence interval (CI) for the difference: -15.9 %, 5.2 %]. The favorable overall response in the PPS population for patients with esophageal candidiasis, invasive candidiasis, and chronic pulmonary aspergillosis including aspergilloma was 100.0 % (6/6), 100.0 % (3/3), and 46.7 % (14/30) in the caspofungin group, and 83.3 % (5/6), 100.0 % (1/1), and 42.4 % (14/33) in the micafungin group, respectively. In Japanese patients with Candida or Aspergillus infections, there was no statistical difference in the safety between caspofungin and micafungin. Consistent with other data on these two agents, the efficacy of caspofungin and micafungin was similar.

Serologic assay to quantify human immunoglobulin G antibodies to the Staphylococcus aureus iron surface determinant B antigen.

A direct binding Luminex assay has been developed and validated for the detection of human immunoglobulin G (IgG) antibodies to the Staphylococcus aureus iron surface determinant B protein (IsdB) in serum following natural infection or immunization with investigational Saccharomyces cerevisiae-derived IsdB-based vaccines. To ensure that IsdB-specific IgG antibodies are measured following immunization with S. cerevisiae-derived IsdB, an Escherichia coli-produced IsdB antigen is used in the assay. The IsdB antigen is covalently conjugated to maleimide microspheres via an engineered carboxy-terminal cysteine residue. Antibody titers are determined in a direct binding format, where the phycoerythrin-labeled monoclonal antibody (HP6043) specific for IgG1 to IgG4 binds to human serum IgG antibodies. Fluorescent signal emitted from bound HP6043 is directly proportional to an individual's antibody levels. A pooled human reference serum from vaccinees with high titers to IsdB is used to generate a 12-point standard curve. The correlation of mean fluorescent intensity (MFI) units to microg/ml of IsdB-specific IgG is made by interpolating the MFI data through a four-parameter curve-fitting algorithm. The assay is sensitive to 1.06 microg/ml with a dynamic range of 2.1 to 10,625 microg/ml. The overall specificity of the assay is >96% and the linearity (parallelism) of the assay is -4% per 10-fold dilution. The total precision of the assay was 16.6% relative standard deviation across three different IsdB antigen lots, three different microsphere lots, two secondary antibody lots, and three different operators. The assay has proven useful for evaluating the immune response following the administration of different dosages and formulations of investigational IsdB-based vaccines.

Efficacy and safety of caspofungin therapy in elderly patients with proven or suspected invasive fungal infections.

Invasive fungal infections (IFIs) are serious complications in elderly adults. Caspofungin may provide a useful therapeutic option for elderly patients with or at high risk for IFIs. We retrospectively compared efficacy and safety outcomes in elderly (> or = 65 years of age) and non-elderly patients in three clinical trials of caspofungin: a double-blind, randomized trial versus amphotericin B for documented invasive candidiasis (IC); an open-label, non-comparative study of definite or probable invasive aspergillosis (IA); and a double-blind, randomized trial versus liposomal amphotericin B as empirical therapy (ET) in febrile neutropenic patients. A total of 159 elderly patients with a median age of 71 years (range, 65-84) received caspofungin in these studies. The median duration of caspofungin therapy was 12 days for IC and ET, and 28 days for IA. Point estimates for the favorable response rates to caspofungin were numerically higher in elderly versus non-elderly patients with IC (83% vs. 68%) or IA (64% vs. 44%) and were similar in patients receiving ET (36% vs. 34%). Adverse events related to caspofungin occurred in generally similar proportions of elderly versus non-elderly patients with IC (clinical, 33% vs. 27%; laboratory, 17% vs. 29%), with IA (clinical, 7% vs. 13%; laboratory, 13% vs. 14%), or receiving ET (clinical, 47% vs. 47%; laboratory, 24% vs. 22%). Nephrotoxicity and infusion-related toxicity developed in comparable proportions of elderly and non-elderly caspofungin recipients in all three studies. In this post-hoc analysis, caspofungin appeared to be as efficacious and well tolerated in elderly patients as in non-elderly patients.

Efficacy and safety of caspofungin in solid organ transplant recipients.

Efficacy and safety data for the echinocandins in solid organ transplant (SOT) recipients are limited. We reviewed data from three clinical trials that enrolled SOT patients receiving caspofungin therapy for an invasive fungal infection (IFI). Caspofungin was administered at doses ranging from 50 to 100 mg/day. Efficacy was assessed in all patients at the end of caspofungin therapy (EOT). Adverse events (AE) and laboratory data were collected from all patients. We identified data from 22 SOT patients (aged 34-67 years) with proven invasive candidiasis (IC; 6 patients) or proven or probable invasive aspergillosis (IA; 16 patients) who received at least one dose of caspofungin therapy. All patients with IC received caspofungin as primary therapy. Caspofungin success against IC at EOT was 83% (5 of 6), with responses seen across Candida spp. Success by SOT type was: kidney 4 of 5 and liver 1 of 1. All 16 patients with IA (all pulmonary) received caspofungin as salvage therapy. Caspofungin success against IA at EOT was 50% (8 of 16), with responses seen for both definite (3 of 4) and probable IA (5 of 12). Success by SOT type was: heart 2 of 2, heart/lung 0 of 2, kidney 3 of 3, liver 1 of 3, and lung 2 of 6. The outcome was not influenced by caspofungin dose. Caspofungin, dosed for 2 to 162 (mean 36.8) days, was well tolerated. No patient had a serious drug-related adverse event or discontinued caspofungin due to toxicity. Based on these limited data, caspofungin appears to be an effective and well-tolerated option for the treatment of IC and IA in SOT recipients.

Retrospective study of the hepatic safety profile of patients concomitantly treated with caspofungin and cyclosporin A.

BACKGROUND: Mild, transient alanine aminotransferase (ALT) elevations were seen in Phase I studies of caspofungin and cyclosporin A (CsA). METHODS: We conducted a retrospective chart review at four sites to characterize the hepatic safety in patients receiving > or =1 day of both drugs over a 20-month period. Investigators assessed reasons for discontinuing concomitant therapy and the presence/etiology of any hepatotoxicity. RESULTS: Forty patients receiving concomitant therapy for 1-290 days (median 17.5 days) were identified. Although common, liver enzyme abnormalities were frequently attributed to other comorbidities or medications. ALT and/or aspartate aminotransferase (AST) elevations occurred in 14 patients (35%). Five had AST elevations at least possibly related to caspofungin/CsA, but none were >3.6 times the normal upper limit. No ALT elevations were related to caspofungin/CsA. Two of 4 patients had discontinuation of therapy because of hepatotoxicity possibly related to caspofungin/CsA. No serious adverse events occurred because of caspofungin. CONCLUSIONS: These data do not suggest a significant risk of clinically relevant hepatotoxicity with concomitant caspofungin/CsA.

Global distribution and outcomes for Candida species causing invasive candidiasis: results from an international randomized double-blind study of caspofungin versus amphotericin B for the treatment of invasive candidiasis.

In a randomized study, caspofungin was compared with amphotericin B for the treatment of invasive candidiasis in a total of 239 adults from 56 sites in 20 countries. This study provided a unique opportunity to assess the frequency and outcome of invasive candidiasis caused by different Candida species worldwide, and the results are presented here. Efficacy was primarily assessed at the end of intravenous therapy using a modified intent-to-treat (MITT) analysis. This analysis was performed on 224 of the 239 patients enrolled in the study. Attempts were made to collect baseline Candida isolates from all patients for species identification at a central laboratory. Yeasts were identified to the species level using two commercial systems and microscopic examination. Viable baseline isolates were recovered from 210 of the 224 (94%) patients included in the MITT analysis. Candida albicans was the most frequently isolated species in all regions and was responsible for 45% of cases overall. Nevertheless, the majority of cases of infection were caused by non- albicans Candida species. In the USA and Canada, Candida glabrata was the second most commonly isolated pathogen (18%). In contrast, Candida parapsilosis and Candida tropicalis accounted for 55% of cases in Latin America. Outcomes were comparable for patients treated with caspofungin (74% overall; 64% and 80% for infections due to Candida albicans and non- albicans species) and amphotericin B (62% overall; 58% and 68% for infections due to Candida albicans and non- albicans species), and were generally similar across continents. The distribution of Candida species isolated from patients enrolled in a clinical trial may not be representative of pathogens causing invasive candidiasis in the general population. Nevertheless, our findings may affect the regional choice of empirical antifungal therapy for seriously ill patients with suspected or documented invasive candidiasis since different Candida species have varying susceptibility to conventional antifungal drugs.

Antiretroviral resistance during successful therapy of HIV type 1 infection.

HIV type 1 (HIV-1) drug resistance mutations were selected during antiretroviral therapy successfully suppressing plasma HIV-1 RNA to <50 copies/ml. New resistant mutant subpopulations were identified by clonal sequencing analyses of viruses cultured from blood cells. Drug susceptibility tests showed that biological clones of virus with the mutations acquired during successful therapy had increased resistance. Each of the five subjects with new resistant mutants had evidence of some residual virus replication during highly active antiretroviral therapy (HAART), based on transient episodes of plasma HIV-1 RNA > 50 copies/ml and virus env gene sequence changes. Each had received a suboptimal regimen before starting HAART. Antiretroviral-resistant HIV-1 can be selected from residual virus replication during HAART in the absence of sustained rebound of plasma HIV-1 RNA.

Clinical monitoring of HIV-1 infection in the ERA of antiretroviral resistance testing.

Viral replication of HIV-1 in the human body is a dynamic process. Incomplete suppression of replication during antiretroviral therapy ultimately selects for resistance that imparts an adaptive advantage to HIV-1. Therefore, the goal of antiretroviral therapy is complete suppression of viral replication. Viral suppression to below the lowest possible limits of detection has been associated with an optimal clinical response and delay of drug resistance. An ultrasensitive viral load assay with a very low threshold of detection remains our best laboratory tool to monitor the response to therapy. Patients may fail HAART for many reasons. Only when other potential causes of treatment failure are excluded should antiretroviral resistance testing be considered. Genotypic and phenotypic assays for assessing resistance are now available, and recent retrospective and prospective data support their use in clinical management as an adjunct to helping to choose among different antiretroviral drugs. Despite the growing enthusiasm for these tests, improvements in sensitivity, turnaround time, and quality control are still needed. A practitioner's decision about when to initiate or change therapy in an HIV-infected patient should depend primarily on viral load results, and not on antiretroviral resistance test results. Moreover, resistance testing is no substitute for a thorough clinical and drug history. As we approach the third decade of the HIV epidemic, we will learn how to use antiretroviral resistance tests in conjunction with (not in lieu of) proven clinical and laboratory tools.

Identification of RFamide neuropeptides in the medicinal leech.

Using a four-step reverse phase HPLC separation and RIA, five RFamide peptides were purified from CNS extracts of the leech Hirudo medicinalis. YMRFamide, FMRFamide, YLRFamide, FLRFamide, and GGKYMRFamide were identified by a combination of antiserum specificity in RIA, Edman degradation, and mass spectrometry. At least three of these five endogenous peptides can modulate neuromuscular interactions in the leech (38). FMRFamide-like immunoreactivity was selectively released from neural processes on isolated heart tubes in the presence of calcium and depolarizing levels of potassium.