First-in-Human Phase 1 Study To Assess Safety, Tolerability, and Pharmacokinetics of a Novel Antifungal Drug, VL-2397, in Healthy Adults.

VL-2397 is an antifungal drug with a novel mechanism of action, rapid fungicidal in vitro activity, and potent in vivo activity against Aspergillus fumigatus, including azole-resistant strains. VL2397-101, a phase 1 first-in-human, randomized, double-blind, placebo-controlled dose-escalation study, was conducted in healthy adults to determine the safety, tolerability, and pharmacokinetics (PK) of single and multiple ascending intravenous (i.v.) doses of VL-2397. All dosing cohorts were fully enrolled; all subjects completed the safety follow-up. A safety committee reviewed the safety data for each dosing cohort prior to recommending the initiation of each subsequent cohort. No serious adverse events (SAEs) occurred; the majority of treatment-emergent adverse events (TEAEs) were mild and self-limited. The most common drug-related TEAEs were infusion site reactions. No clinically concerning trends were noted in vital signs, electrocardiograms, physical examinations, or safety laboratory results. Following single infusions of VL-2397, the overall and maximum exposures rose less than proportionally with increasing doses from 3 mg to 1,200 mg as indicated by area under the concentration-time curve over 24 h (AUC24) and maximum concentration (Cmax). No signs of VL-2397 accumulation were observed following i.v. infusions of 300, 600, and 1,200 mg every 24 h (q24h) for 7 days. Renal elimination played a major role in total body clearance, with up to 47% of unmetabolized drug in urine 24 h after administration at single doses of >30 mg. Overall, VL-2397 dosing in the study appeared to be safe and well tolerated in the healthy subjects. The safety profile, consistent PK, and lack of drug accumulation support further development of VL-2397 in patients with invasive aspergillosis.

Phase 1 clinical trials of the safety and immunogenicity of adjuvanted plasmid DNA vaccines encoding influenza A virus H5 hemagglutinin.

BACKGROUND: Development of vaccines against highly pathogenic avian influenza virus H5N1 subtypes posing a pandemic threat remains a priority. Limitations in manufacturing capacity and production time of conventional inactivated vaccines highlight the need for additional approaches. METHODS: We conducted two double-blind, placebo-controlled phase 1 studies involving a total of 103 healthy adults who received two intramuscular injections of Vaxfectin-adjuvanted plasmid DNA vaccine or placebo 21 days apart. Vaccine cohorts received either a monovalent vaccine containing an A/Vietnam/1203/04 H5 hemagglutinin-encoding plasmid or a trivalent vaccine with plasmids encoding H5, NP, and M2 proteins in doses from 0.1 to 1mg of DNA/injection. RESULTS: All doses were well tolerated without vaccine-related serious adverse events or discontinuations. In the monovalent cohorts, hemagglutination inhibition (HI) titers of > or =40 and 4-fold rises from baseline were achieved in 47-67% of subjects and H5-specific T-cell responses in 75-100%. Trivalent cohorts had lower HI response rates (< or = 20%), but 72% of subjects achieved T-cell and/or antibody responses to one or more antigens. CONCLUSIONS: Vaxfectin-adjuvanted monovalent H5 DNA vaccines were well tolerated and induced HI response rates and titers in the reported range of inactivated protein-based H5 vaccines, suggesting that adjuvanted DNA vaccines with rapid vaccine production could be useful for pandemic control.

Density Functional and Electrostatic Calculations of Manganese Superoxide Dismutase Active Site Complexes in Protein Environments.

Density functional and electrostatic methods have been applied to calculate active site geometries and the redox potential of manganese superoxide dismutase (MnSOD). The initial active site clusters were built up by including only first-shell side chain ligands and then augmented by second-shell ligands. The density functional optimized Mn-ligand bond lengths for the reduced complexes in general compared fairly well with protein crystallography data; however, large deviations for calculated Mn-OH distances were found for the oxidized active site clusters. Our calculations suggest that this deviation can be attributed to the redox heterogeneity of the oxidized protein in X-ray crystallography studies. The redox potential was calculated by treating the protein environment and the solvent bulk by a semimacroscopic electrostatic model. The protein structures were taken from the Thermus thermophilus enzyme. The calculated coupled redox potentials converge toward experimental values with increasing size of the active site cluster models, and the final calculated value was +0.06 V, compared to experimental values of +0.26 V determined for Bacillus stearothermophilus and +0.31 V in Escherichia coli enzymes. Using an energy decomposition scheme, the effects of the second-shell ligands and the protein and reaction fields have been analyzed.

CuZn Superoxide Dismutase Geometry Optimization, Energetics, and Redox Potential Calculations by Density Functional and Electrostatic Methods.

The structures, energetics, and orbital- and charge-dependent properties of copper zinc superoxide dismutase (CuZnSOD) have been studied using density functional and electrostatic methods. The CuZnSOD was represented with a model consisting of copper and zinc sites connected by a bridging histidine ligand. In addition to the bridge, three histidine ligands and one water molecule were bonded to the Cu ion in the copper site as first-shell ligands. Two histidine ligands and an aspartate were coordinated to the zinc ion in the zinc site. Full optimization of the model was performed using different functionals, both local and nonlocal. Geometrical parameters calculated with the nonlocal functionals agree well with the experimental X-ray data. In our calculated results, the His61 Nepsilon-Cu bond in the active site breaks during the reduction and protonation, consistent with a number of X-ray structures and with EXAFS and NMR evidence. The reduction potential and pK(a) of the coupled electron/proton reaction catalyzed by CuZnSOD were determined using different models for the extended environment-from an electrostatic representation of continuum solvent, to the full protein/solvent environment using a Poisson-Boltzmann method. The predicted redox potential and pK(a) values determined using the model with the full protein/solvent environment are in excellent agreement with experiment. Inclusion of the full protein environment is essential for an accurate description of the redox process. Although the zinc ion does not play a direct redox role in the dismutation, its electronic contribution is very important for the catalytic mechanism.