Pharmacokinetics and safety evaluation of oral Palonosetron in Chinese healthy volunteers: A phase 1, open-label, randomized, cross-over study.

PURPOSE: Palonosetron hydrochloride is a specific 5-HT3 receptor antagonist, used to prevent chemotherapy-induced nausea and vomiting (CINV), and is a known chemical entity currently registered in the oral and IV forms in several countries worldwide. METHODS: Single-center, single-dose, 3-treatment, open-label, randomized, 3-period, phase-I cross-over study, conducted in 18 individuals (16 males and 2 females). The primary objective was to assess the pharmacokinetic profile of Palonosetron 0.25, 0.5 and 0.75mg, after a single, oral administration in Chinese male and female healthy volunteers. RESULTS: After administration of a single oral dose of 0.25mg, 0.5mg, or 0.75mg palonosetron in Chinese male and female healthy subjects, plasma palonosetron concentrations reached maximum values (Cmax) of 673 ± 151 pg/mL, 1330 ± 258 pg/mL, and 1990 ± 490 pg/mL, respectively, at 3-5 h (tmax). The plasma elimination half-life for 0.25, 0.5 and 0.75 mg of palonosetron was 41.8±9.72 hours, 44.6±8.59 hours and 42.3±8.51 hours, respectively. Single oral doses of 0.25mg, 0.5mg, or 0.75mg palonosetron were safe and well tolerated among all the 18 subjects involved. CONCLUSIONS: The PK of palonosetron was found to be linear in the dose range of 0.25 to 0.75 mg. Oral palonosetron in doses up to 0.75 mg was well tolerated in healthy Chinese subjects. The PK and safety data obtained from this study were similar to previous phase I studies with IV palonosetron.

A phase 1 pharmacokinetic study of oral NEPA, the fixed combination of netupitant and palonosetron, in Chinese healthy volunteers.

PURPOSE: Oral NEPA, the only fixed-combination antiemetic, is composed of the neurokinin-1 receptor antagonist netupitant (300 mg) and the 5-hydroxytryptamine-3 receptor antagonist palonosetron (0.50 mg). This study was conducted to evaluate the pharmacokinetic profile of netupitant and its main metabolites M1 and M3, and palonosetron in Chinese subjects. Oral NEPA tolerability and safety were also analyzed. METHODS: This was a single-center, single-dose phase 1 study in healthy, adult Chinese volunteers. Eligible subjects received oral NEPA, and blood samples were collected on day 1 predose and at various time points up until day 10 postdose. Pharmacokinetic parameters were analyzed using noncompartmental methods. For safety assessments, adverse events (AEs) were monitored during the study. RESULTS: In total 18 Chinese healthy volunteers received oral NEPA. Netupitant mean maximum plasma concentration (Cmax) [± standard deviation] of 698 ± 217 ng/mL was reached at 3-6 h, with a mean total exposure (AUC0-inf) of 22,000 ± 4410 h·ng/mL. For palonosetron, a mean Cmax of 1.8 ± 0.252 ng/mL was reached at 2-6 h postadministration, with a mean AUC0-inf of 81.0 ± 14.0 h·ng/mL. The most common treatment-related AEs in > 2 subjects were constipation (n = 9) and tiredness (n = 3). No severe AEs were observed, and no subject withdrew due to AEs. CONCLUSION: Following single-dose administration of oral NEPA in Chinese subjects, the pharmacokinetic profiles of the NEPA components were mostly similar to those reported previously in Caucasians. NEPA was well tolerated with a safety profile in line with that observed in pivotal trials in Caucasians.

Efficacy of NEPA, a fixed antiemetic combination of netupitant and palonosetron, vs a 3-day aprepitant regimen for prevention of chemotherapy-induced nausea and vomiting (CINV) in Chinese patients receiving highly emetogenic chemotherapy (HEC) in a randomized Phase 3 study.

NEPA is the only fixed combination antiemetic, comprised of an NK1 RA (netupitant) and a 5-HT3 RA (palonosetron). In the first head-to-head trial to compare NK1 RA-containing regimens, a single oral dose of NEPA was non-inferior to a 3-day aprepitant/granisetron (APR/GRAN) regimen for the primary endpoint of overall (0-120 hours) complete response (no emesis/no rescue). This pre-specified analysis evaluates the efficacy of NEPA versus APR/GRAN in the subset of Chinese patients in the study. In addition, efficacy in patients at greatest emetic risk receiving high-dose cisplatin (≥70 mg/m2 ) was explored. Chemotherapy-naïve patients with solid tumors in this randomized, double-blind study received either a single dose of NEPA prior to cisplatin-based chemotherapy or a 3-day regimen of APR/GRAN, both with dexamethasone on Days 1-4. Efficacy was evaluated through complete response, no emesis, and no significant nausea rates during the acute (0-24 hours), delayed (25-120 hours) and overall phases as well as individual days post-chemotherapy, as the daily course of CINV protection is often unstudied. The Chinese subset included 667 patients; of these, 363 (54%) received high-dose cisplatin. Baseline characteristics were comparable. While response rates were similar for NEPA and APR/GRAN during the acute, delayed and overall phases, significantly fewer NEPA patients experienced breakthrough CINV on individual Days 3-5 in both the Chinese patients and also in those receiving high-dose cisplatin. As a fixed oral NK1 RA/5HT3 RA combination given once/cycle, NEPA is a convenient highly effective prophylactic antiemetic that may offer better protection from CINV than a 3-day APR/GRAN regimen on Days 3-5 following highly emetogenic chemotherapy.

Issues of ligand accessibility and mobility in initial cell attachment.

The influence of lateral ligand mobility on cell attachment and receptor clustering has previously been explored for membrane-anchored molecules involved in cell-cell adhesion. In this study, we considered instead a cell binding motif from the extracellular matrix. Even though the lateral mobility of extracellular matrix ligands in membranes does not occur in vivo, we believe it is of interest for cell engineering in vitro. As is the case for cell-cell adhesion molecules, lateral mobility of extracellular matrix ligands could influence cell attachment and, subsequently, cell behavior in cell culture. In this paper, the accessibility and functionality of extracellular matrix ligands presented at surfaces were evaluated for the conditions of laterally mobile versus non-mobile ligands by studying ligand-antibody binding events and early cell attachment as a function of ligand concentration. We compare the initial attachment of rat-derived adult hippocampal progenitor (AHP) cells on laterally mobile, supported phospholipid bilayer membranes to non-mobile, poly-L-lysine-grafted-poly(ethylene glycol) (PLL-g-PEG) polymer films functionalized with a range of laminin-derived IKVAV-containing peptide densities. To this end, synthesis of a new PLL-g-PEG/PEG-IKVAV polymer is described. The characterization of available IKVAV peptides on both surface presentations schemes was explored by studying the mass uptake of anti-IKVAV antibodies using a combination of the surface-sensitive techniques quartz crystal microbalance with dissipation monitoring, surface plasmon resonance spectroscopy, and optical waveguide lightmode spectroscopy. IKVAV-containing peptides presented on laterally mobile, supported phospholipid bilayers and non-mobile PLL-g-PEG were recognized by the anti-IKVAV antibody in a dose-dependent manner, indicating that the amount of available IKVAV ligands increases proportionally with ligand density over the concentrations tested. Attachment of AHP cells to IKVAV-functionalized PLL-g-PEG and supported phospholipid bilayers followed a sigmoidal dependence on peptide concentration, with a critical concentration of approximately 3 pmol/cm2 IKVAV ligands required to support initial AHP cell attachment for both surface modifications. There appeared to be little influence of IKVAV peptide mobility on the initial attachment of AHP cells. Although the spread in the cell attachment data was larger for the PLL-g-PEG surface modification, this was reduced when observed after 24 h, indicating that the cells might need longer times to establish attachment strengths equivalent to those observed on peptide-functionalized supported lipid bilayers. The present study is a step toward understanding the influence of extracellular-matrix-derived ligand mobility on cell fate. Further analysis should focus on the systematic tuning of lateral ligand diffusion, as well as a comparison between the response of non-spreading cells (i.e., AHPs), versus spreading cells (i.e., fibroblasts).

The production of de novo folded proteins by a stepwise chain elongation: a model for prebiotic chemical evolution of macromolecular sequences.

We describe an experimental procedure to mimic the formation of long (over 40 residues) co-oligopetide sequences in many identical copies which may have occurred in the prebiotic molecular evolution. The basic hypothesis is that chain formation is based on the stepwise fragment condensation of randomly generated short oligopeptides, whereby the elongation takes place under the contingent environmental constraints (solubility, pH, salinity), which eliminate most of the products, and thus determine the selection towards one particular small set of chains. The present work aims at verifying the validity of this scheme. In order to do so, we utilize a classic synthetic procedure based on the Merrifield solid-phase synthesis of peptides for the synthesis of randomly produced peptides as well as for their stepwise fragment condensation. Thus, starting from a library of peptides with n=10, the first condensation step produces a library of 16 peptides with 20 residues each (n=20), of which only four remain water-soluble and, therefore, capable to undergo the next fragment condensation step. This gives rise to 16 peptides with n=30, out of which twelve precipitate out under the chosen pH and buffer conditions and are eliminated. Finally, a 44-residue-long water-soluble de novo protein is obtained. This has no homologies or similarities with extant proteins, and, based on circular dichroism (CD), it assumes a stable three-dimensional folding. In agreement with CD data, molecular-modelling simulations suggest an helical fold for the protein with poor, if any, structural homology with known proteins. The implication of this procedure as a general mechanism for the etiology of de novo macromolecular sequences and globular proteins in the origin of life is briefly discussed.