Niraparib Population Pharmacokinetics and Exposure-Response Relationships in Patients With Newly Diagnosed Advanced Ovarian Cancer.

PURPOSE: Niraparib is a poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitor approved for the maintenance treatment of advanced ovarian cancer (OC). Niraparib was originally approved in recurrent OC at a fixed starting dose (FSD) of 300 mg once daily (QD). This analysis characterized the population pharmacokinetics (PK) of niraparib and evaluated the relationships between exposure, efficacy, and safety to support clinical use of an individualized dosing strategy, in which the starting dose of niraparib was adjusted based on patient characteristics to improve the benefit-risk profile. METHODS: A population PK model was developed by pooling data from four niraparib clinical trials (PN001 [n = 104], QUADRA [n = 455], NOVA [n = 403], and PRIMA [n = 480]) in patients with solid tumors, including OC. Exposure-response analyses were conducted to explore the relationships of niraparib exposure with progression-free survival (PFS) and adverse events in the PRIMA study. A multivariate logistic regression model was also developed to estimate the probability of grade ≥3 thrombocytopenia, using data from patients enrolled in PRIMA and NOVA. The impact of an individualized starting dose (ISD) regimen (200 mg QD in patients with body weight [BW] <77 kg or platelet count [PLT] <150,000/µL, or 300 mg QD in patients with BW ≥77 kg and PLT ≥150,000/µL) on systemic exposure, efficacy, and safety was assessed. FINDINGS: Niraparib disposition was best described by a 3-compartment model with linear elimination. Key covariates included baseline creatinine clearance, BW, albumin, and age, all of which had minor effects on niraparib exposure. Comparable model-predicted exposure up to the time of disease progression/death or censoring in the 300-mg FSD and 200-/300-mg ISD groups was consistent with the lower rate of dose reduction in the ISD groups. No consistent niraparib exposure-response relationship was observed for efficacy in all PRIMA patients (first-line OC), and no statistically significant difference was seen in PFS curves for patients receiving a niraparib dose of 200 mg versus 300 mg. In the multivariate regression model, performed using combined data from PRIMA and NOVA, higher niraparib exposure (area under the concentration-time curve at steady-state [AUCss]), lower BW, and lower PLT were associated with an increased risk of grade ≥3 thrombocytopenia. IMPLICATIONS: Population PK and exposure-response analyses support use of an ISD to improve the safety profile of niraparib, including reducing the rate of grade ≥3 thrombocytopenia, without compromising efficacy. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01847274 (NOVA), NCT00749502 (PN001), NCT02655016 (PRIMA), NCT02354586 (QUADRA), www. CLINICALTRIALS: gov.

Large-scale snake genome analyses provide insights into vertebrate development.

Snakes are a remarkable squamate lineage with unique morphological adaptations, especially those related to the evolution of vertebrate skeletons, organs, and sensory systems. To clarify the genetic underpinnings of snake phenotypes, we assembled and analyzed 14 de novo genomes from 12 snake families. We also investigated the genetic basis of the morphological characteristics of snakes using functional experiments. We identified genes, regulatory elements, and structural variations that have potentially contributed to the evolution of limb loss, an elongated body plan, asymmetrical lungs, sensory systems, and digestive adaptations in snakes. We identified some of the genes and regulatory elements that might have shaped the evolution of vision, the skeletal system and diet in blind snakes, and thermoreception in infrared-sensitive snakes. Our study provides insights into the evolution and development of snakes and vertebrates.

Genome of Laudakia sacra Provides New Insights into High-Altitude Adaptation of Ectotherms.

Anan's rock agama (Laudakia sacra) is a lizard species endemic to the harsh high-altitude environment of the Qinghai-Tibet Plateau, a region characterized by low oxygen tension and high ultraviolet (UV) radiation. To better understand the genetic mechanisms underlying highland adaptation of ectotherms, we assembled a 1.80-Gb L. sacra genome, which contained 284 contigs with an N50 of 20.19 Mb and a BUSCO score of 93.54%. Comparative genomic analysis indicated that mutations in certain genes, including HIF1A, TIE2, and NFAT family members and genes in the respiratory chain, may be common adaptations to hypoxia among high-altitude animals. Compared with lowland reptiles, MLIP showed a convergent mutation in L. sacra and the Tibetan hot-spring snake (Thermophis baileyi), which may affect their hypoxia adaptation. In L. sacra, several genes related to cardiovascular remodeling, erythropoiesis, oxidative phosphorylation, and DNA repair may also be tailored for adaptation to UV radiation and hypoxia. Of note, ERCC6 and MSH2, two genes associated with adaptation to UV radiation in T. baileyi, exhibited L. sacra-specific mutations that may affect peptide function. Thus, this study provides new insights into the potential mechanisms underpinning high-altitude adaptation in ectotherms and reveals certain genetic generalities for animals' survival on the plateau.

The structural and functional divergence of a neglected three-finger toxin subfamily in lethal elapids.

Bungarus multicinctus is a widely distributed and medically important elapid snake that produces lethal neurotoxic venom. To study and enhance existing antivenom, we explore the complete repertoire of its toxin genes based on de novo chromosome-level assembly and multi-tissue transcriptome data. Comparative genomic analyses suggest that the three-finger toxin family (3FTX) may evolve through the neofunctionalization of flanking LY6E. A long-neglected 3FTX subfamily (i.e., MKA-3FTX) is also investigated. Only one MKA-3FTX gene, which evolves a different protein conformation, is under positive selection and actively transcribed in the venom gland, functioning as a major toxin effector together with MKT-3FTX subfamily homologs. Furthermore, this lethal snake may acquire self-resistance to its ß-bungarotoxin via amino acid replacements on fast-evolving KCNA2. This study provides valuable resources for further evolutionary and structure-function studies of snake toxins, which are fundamental for the development of effective antivenoms and drug candidates.

The technology of artificial pneumoperitoneum CT and its application in diagnosis of abdominal adhesion.

To retrospectively analyze the use of artificial pneumoperitoneum in CT scans, to explore its operation methods and technical points, and to lay the foundation for the widespread application of artificial pneumoperitoneum in CT. A total of 331 patients who underwent artificial pneumoperitoneum with CT angiography from January 1, 2013, to November 1, 2019, were recruited. All patients underwent standardized artificial pneumoperitoneum in the horizontal, left and right lateral, and prone positions during CT thin-layer scans of the abdomen and 3D reconstruction. Taking the surgical results as the gold standard, and using kappa test to verify the consistency of surgical results and imaging results. In all 331 patients, 43 patients had a normal peritoneal space, and 288 patients had an abnormal peritoneal space. And only 22 patients developed complications of subcutaneous emphysema, accounting for 6.6% of all 331 patients. In terms of the postoperative results, 28 were normal, and 303 were abnormal. The sensitivity, specificity and accuracy of CT diagnosis of abdominal adhesions using artificial pneumoperitoneum were 100%, 95.04%, and 95.46%, respectively. According to the Kappa consistency test, the imaging diagnosis from the CT scan with artificial pneumoperitoneum had a high consistency with the surgical results (kappa = 0.796, P < 0.05). The technique of artificial pneumoperitoneum CT is safe, reliable, highly practical, and proficient for obtaining good imaging results. It provides a good imaging basis for the diagnosis of intra-abdominal diseases, especially intra-abdominal adhesions.

Pharmacokinetics and safety of niraparib in patients with moderate hepatic impairment.

PURPOSE: The purpose of this study is to characterize niraparib pharmacokinetics (PK) and safety in patients with normal hepatic function (NHF) versus moderate hepatic impairment (MHI). METHODS: Patients with advanced solid tumors were stratified by NHF or MHI (National Cancer Institute-Organ Dysfunction Working Group criteria [bilirubin > 1.5-3 × upper limit of normal and any aspartate aminotransferase elevation]). In the PK phase, all patients received one 300 mg dose of niraparib. In the extension phase, patients with MHI received niraparib 200 mg daily; patients with NHF received 200 or 300 mg based on weight (< 77 kg, ≥ 77 kg)/platelets (< 150,000/µL, ≥ 150,000/µL). PK parameters included maximum concentration (Cmax), area under the curve to last measured concentration (AUClast) and extrapolated to infinity (AUCinf). Safety was assessed in both phases. Exposure-response (E-R) modeling was used to predict MHI effects on exposure and safety of niraparib doses ≤ 200 mg or 300/200 mg or 200/100 mg weight/platelet regimens. RESULTS: In the PK phase (NHF, n = 9; MHI, n = 8), mean niraparib Cmax was 7% lower in patients with MHI versus NHF. Mean exposure (AUClast, AUCinf) was increased by 45% and 56%, respectively, in patients with MHI without impacting tolerability. In the extension phase (NHF, n = 8; MHI, n = 7), the overall safety profile was consistent with previous trials. In patients with MHI, E-R modeling predicted niraparib 200 mg reduced Grade ≥ 3 thrombocytopenia incidence, whereas a 200/100 mg regimen yielded exposures below efficacy-associated levels in 15% of patients. CONCLUSION: These findings support adjusting the 300 mg niraparib starting dose to 200 mg QD in patients with MHI. TRIAL REGISTRATION: NCT03359850; registered December 2, 2017.

Ratiometric fluorescence detection of sulfide ions based on lanthanide coordination polymer using guanosine diphosphate as ligand.

The efficiency of energy transfer from guanine nucleotide to terbium ion (Tb3+) is affected by the phosphate group significantly. Compared with the biomolecules 5'-GMP (guanosine monophosphate), guanosine diphosphate (GDP) exhibits better sensitize ability to Tb3+ ions luminescence. Assisted with the carboxycoumarin ligand, we synthesized a more stable optical Coumarin@GDP-Tb polymer with the characteristic emission peaks located on 440 nm and 545 nm in this work. The Coumarin@GDP-Tb polymer is not only rich in metal binding sites, but also maintains a moderate ionic binding force, which helps metal ions to bind or leave it easily. Experiment result shows that Coumarin@GDP-Tb polymer has the appropriate binding force for Fe2+ ions, which can be destroyed by sulfur ions (S2-) as the formation of FeS precipitation. Based on this, Coumarin@GDP-Tb was designed as the ratio fluorescence probe for sulfur ions detection, where the fluorescence at 545 nm can be selectively quenched by Fe2+ ions, while that at 440 nm was unaffected, in the presence of S2- ions, the quenched fluorescence can be recovered remarkably. With the increasing S2- ions from 0.1-45 µM, the ratio of fluorescence intensity at 545 nm to 440 nm (F545/F440) is linear to S2- concentration, and the detection limit of S2- was calculated to be 0.073 µM. Contrast to those fluorescence probes with single wavelength emission, Coumarin@GDP-Tb displays a comparable sensitivity, the introduced self-adjust wavelength improved the detection accuracy efficiently. The above 98.1 % recovery rates of S2- ions in the actual water sample demonstrated the practicability of Coumarin@GDP-Tb fluorescence probe.

Phase I Pharmacokinetic Study of Niraparib in Chinese Patients with Epithelial Ovarian Cancer.

LESSONS LEARNED: Pharmacokinetics characteristics of niraparib in Chinese patients were similar to those in white patients. Niraparib could be well tolerated by Chinese patients, and adverse events were manageable in this study. Population pharmacokinetics analysis indicated that baseline body weight had a modest impact on pharmacokinetics parameters of niraparib; however, it was not considered clinically important. BACKGROUND: This randomized, open-label, single-arm, phase I study was designed to investigate the pharmacokinetics (PK) and safety of niraparib in Chinese patients with epithelial ovarian cancer. METHODS: Eligible patients were randomized in a 1:1:1 ratio to receive 100, 200, or 300 mg of niraparib once daily. PK parameters were analyzed after single and multiple dose administrations. RESULTS: Thirty-six Chinese patients were enrolled in total. Niraparib was rapidly absorbed after administration, and median time-to-peak (Tmax ) was 3 hours. The long terminal elimination half-life (T1/2 ∼ 35 hours) supports once-daily dosing regimen. The exposure to niraparib showed linear and dose-proportional pharmacokinetics, whereas other PK parameters such as Tmax , T1/2 , and accumulation ratio were dose independent. Population PK analysis indicated that there was no effect of race on niraparib PK parameters, whereas baseline body weight had a modest impact on niraparib exposure. Grade 3/4 treatment-emergent adverse events (TEAEs; reported in ≥10% of patients) included platelet count decreased (a total of five patients who were all from the 300-mg group) and neutrophil count decreased. The TEAEs were manageable after dose modification. CONCLUSION: The PK profile of niraparib in Chinese patients is consistent with that in white patients. Niraparib is safe and well tolerated in Chinese patients with ovarian cancer.

Population Pharmacokinetics of Rolapitant in Patients With Chemotherapy-Induced Nausea and Vomiting.

Population pharmacokinetics of rolapitant and its active metabolite M19 were studied in 482 patients receiving this neurokinin-1 receptor antagonist in combination with a 5-hydroxytryptamine-3 receptor antagonist and dexamethasone for prevention of chemotherapy-induced nausea and vomiting (CINV). Patients received a single dose of rolapitant (range, 9-180 mg) before administration of moderately or highly emetogenic chemotherapy. Population pharmacokinetic analysis was performed via nonlinear mixed-effects modeling. Rolapitant pharmacokinetics was best characterized by a 2-compartment model. Population typical values were estimated to be 0.962 L/h for apparent oral clearance and 214 L for central compartment volume of distribution. The intercompartment clearance and peripheral compartment volume of distribution was estimated to be 2.79 L/h and 164 L, respectively. Metabolite M19 pharmacokinetics was described by a 1-compartment model with an apparent metabolite clearance of 1.83 L/h. Intersubject variability was moderate for pharmacokinetics parameters. Weight positively correlated with central compartment volume of distribution and peripheral compartment volume of distribution but not with apparent oral clearance. No other demographic, clinical, or pathophysiologic covariates, including liver and renal function, influenced rolapitant pharmacokinetics. A slight positive trend was observed between rolapitant exposure and efficacy (ie, complete response defined as no emesis and no use of rescue medication) in the delayed phase of CINV (>24-120 hours after chemotherapy). This further supports the 180-mg dose of rolapitant in CINV patients. In summary, this validated population pharmacokinetic model satisfactorily describes pharmacokinetics of rolapitant and M19 in patients with CINV. These results support the recommendation that no dose adjustment for patient variables investigated is necessary.

A phase 1, open-label, dose-escalation trial of oral TSR-011 in patients with advanced solid tumours and lymphomas.

BACKGROUND: Anaplastic lymphoma kinase (ALK) gene rearrangements are oncogenic drivers in non-small-cell lung cancer (NSCLC). TSR-011 is a dual ALK and tropomyosin-related kinase (TRK) inhibitor, active against ALK inhibitor resistant tumours in preclinical studies. Here, we report the safety, tolerability and recommended phase 2 dose (RP2D) of TSR-011 in patients with relapsed or refractory ALK- and TRK-positive advanced cancers. METHODS: In this sequential, open-label, phase 1 trial (NCT02048488), patients received doses of 30 mg, escalated to 480 mg every 24 hours (Q24h), followed by an expansion cohort of patients with ALK-positive cancers. The primary objective was to evaluate safety and tolerability. Secondary objectives included pharmacokinetics. RESULTS: TSR-011 320- and 480-mg Q24h doses exceeded the maximum tolerated dose. At the RP2D of 40 mg every 8 hours (Q8h), the most common grade 3-4 treatment-emergent adverse events occurred in 3.2-6.5% of patients. Of 14 ALK inhibitor-naive patients with ALK-positive NSCLC, 6 experienced partial responses and 8 had stable disease. CONCLUSIONS: At the RP2D (40 mg Q8h), TSR-011 demonstrated a favourable safety profile with acceptable QTc changes. Limited clinical activity was observed. Based on the competitive ALK inhibitor landscape and benefit/risk considerations, further TSR-011 development was discontinued. CLINICAL TRIAL REGISTRATION NUMBER: NCT02048488.

Effect of niraparib on cardiac repolarization in patients with platinum-sensitive, recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancer.

PURPOSE: Anticancer drugs may cause cardiovascular toxicities, including QT interval prolongation. Niraparib, a potent and selective once-daily oral poly (ADP-ribose) polymerase inhibitor, is approved as a maintenance therapy in platinum-sensitive recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancer (EOC). Here, we present the effects of niraparib on cardiac repolarization, and the correlation between changes in baseline QT interval corrected by Fridericia's formula (ΔQTcF) and niraparib plasma concentrations. METHODS: Patients with EOC from the NOVA study (subset of n = 15), the food effect NOVA substudy (n = 17), and a QTc substudy (n = 26) underwent intensive electrocardiographic (ECG) monitoring that included triplicate ECG testing on Day 1 at baseline (predose) and at 1, 1.5, 2, 3, 4, 6, and 8 h postdose concurrent with time-matched blood sampling for determination of niraparib plasma concentrations. All patients received once-daily 300-mg niraparib until disease progression or toxicity. RESULTS: Across the 3 substudies, the upper limit of the two-sided 90% confidence interval (CI) of ΔQTcF was ≤ 10 ms at every postdose timepoint, with a maximum upper limit of 4.3 ms, which indicates no clinically meaningful effect on QTc prolongation. No statistically significant relationship between ΔQTcF and niraparib plasma concentration was observed (estimated slope: 0.0049; 95% CI: - 0.0020, 0.0117; P = 0.164). There were no clinically relevant changes in other ECG parameters that could be attributable to niraparib. CONCLUSION: Niraparib administration at the recommended daily dose of 300 mg for EOC is not associated with clinically relevant alteration of ECGs, including QTc prolongation.

An Open-Label, Randomized, Pivotal Bioequivalence Study of Oral Rolapitant.

Rolapitant, a selective and long-acting neurokinin-1 receptor antagonist, is approved in an oral formulation for prevention of delayed chemotherapy-induced nausea and vomiting in adults. This pivotal open-label, randomized, single-dose, multicenter, parallel-group study assessed the bioequivalence of a single oral dose of 180 mg of rolapitant administered in tablet (2 × 90-mg tablets) or capsule (4 × 45-mg capsules) form in healthy male and female subjects. Blood samples for pharmacokinetic analysis were collected predose and at times up to 912 hours postdose. The rolapitant tablet was considered bioequivalent to the rolapitant capsule if the 90% confidence intervals for the ratios of the geometric means for rolapitant, observed maximum plasma concentration (Cmax ), and area under the curve from time 0 extrapolated to infinity (AUC0-∞ ) were within the 0.80-1.25 range. The pharmacokinetic profiles of the capsule group (n = 43) and tablet group (n = 44) were similar. The geometric mean ratios of Cmax and AUC0-∞ were 0.99 (0.89-1.11) and 1.05 (0.92-1.19), respectively, establishing bioequivalence of the rolapitant tablet and capsule formulations. Both formulations were well tolerated, with a similar incidence of treatment-emergent adverse events in the 2 groups.

Pharmacokinetics, Safety, and Tolerability of Rolapitant Administered Intravenously Following Single Ascending and Multiple Ascending Doses in Healthy Subjects.

Rolapitant is a selective and long-acting neurokinin-1 receptor antagonist approved in an oral formulation in combination with dexamethasone and a 5-hydroxytryptamine type 3 receptor antagonist for the prevention of delayed chemotherapy-induced nausea and vomiting in adults. The pharmacokinetic and safety profiles of intravenous (IV) rolapitant were evaluated in two open-label, phase 1 trials in healthy subjects. Single ascending dose (SAD) and multiple ascending dose studies were conducted in one trial (PR-11-5012-C), and a supratherapeutic SAD study was conducted in a separate trial (PR-11-5022-C). In the SAD and supratherapeutic studies, rolapitant maximum plasma concentration, area under the plasma drug concentration-time curve (AUC) from time zero to time of last measured concentration, and AUC from time zero to infinity increased dose-proportionally following single IV infusions of 18 to 270 mg. In the multiple ascending dose study, following 10 daily IV infusions of rolapitant 18, 36, or 54 mg, the mean day 10:day 1 maximum concentration ratio was 1.97, 1.52, and 2.07, respectively, and the mean day 10:day 1 ratio of AUC from 0 to 24 hours was 4.30, 4.59, and 5.38, respectively, indicating drug accumulation over time. Across all studies, rolapitant was gradually eliminated from plasma, with a half-life of 135-231 hours. Rolapitant was safe and well tolerated across all studies, with no serious or severe rolapitant-related treatment-emergent adverse events. The most common rolapitant-related treatment-emergent adverse events were headache, dry mouth, and dizziness, which were predominantly mild in severity. Overall, the pharmacokinetic and safety profiles of IV rolapitant were consistent with those of the oral formulation.

Pharmacokinetic Interactions of Rolapitant With Cytochrome P450 3A Substrates in Healthy Subjects.

Rolapitant (Varubi) is a neurokinin-1 receptor antagonist approved for the prevention of chemotherapy-induced nausea and vomiting. Rolapitant is primarily metabolized by the cytochrome P450 3A4 (CYP3A4) enzyme. Unlike other neurokinin-1 receptor antagonists, rolapitant is neither an inhibitor nor an inducer of CYP3A4 in vitro. The objective of this analysis was to examine the pharmacokinetics of rolapitant in healthy subjects and assess drug-drug interactions between rolapitant and midazolam (a CYP3A substrate), ketoconazole (a CYP3A inhibitor), or rifampin (a CYP3A4 inducer). Three phase 1, open-label, drug-drug interaction studies were conducted to examine the pharmacokinetic interactions of orally administered rolapitant with midazolam, rolapitant with ketoconazole, and rolapitant with rifampin. The pharmacokinetic profiles of midazolam and 1-hydroxy midazolam metabolites were essentially unchanged when coadministered with rolapitant, indicating the lack of a clinically relevant inhibition or induction of CYP3A by rolapitant. Coadministration of ketoconazole with rolapitant had no effects on rolapitant maximum concentration and resulted in an approximately 20% increase in the area under the concentration-time curve of rolapitant, suggesting that strong CYP3A inhibitors have minimal inhibitory effects on rolapitant exposure. Repeated administrations of rifampin appeared to reduce rolapitant exposure, resulting in a 33% decrease in maximum concentration and 87% decrease in area under the concentration-time curve from time zero to infinity. Coadministration of rolapitant did not affect the exposure of midazolam. Rifampin coadministration resulted in lower concentrations of rolapitant, and ketoconazole coadministration had no or minimal effects on rolapitant exposure. Rolapitant was safe and well tolerated when coadministered with ketoconazole, rifampin, or midazolam. No new safety signals were reported compared with previous studies of rolapitant.

A Phase 1 Assessment of the QT Interval in Healthy Adults Following Exposure to Rolapitant, a Cancer Supportive Care Antiemetic.

This 2-part study evaluated the QT/QTc prolongation potential and safety and pharmacokinetics of the antiemetic rolapitant, a neurokinin-1 receptor antagonist. Part 1 was a randomized, placebo-controlled single-dose-escalation study assessing the safety of a single high dose of rolapitant. Part 2 was a randomized, placebo- and positive-controlled, double-blind parallel-group study including 4 treatment arms: rolapitant at the highest safe dose established in part 1, placebo, moxifloxacin 400 mg (positive control), and rolapitant at the presumed therapeutic dose (180 mg). Among 184 adults, rolapitant was absorbed following oral administration under fasting conditions, with a median Tmax of 4 to 6 hours (range, 2-8 hours) and was safe at all doses up to 720 mg. No differences in mean change in QTcF were observed between placebo and rolapitant from baseline or at any point. At any point, the upper bound of the confidence interval for the mean difference between placebo and rolapitant was no greater than 4.4 milliseconds, and the mean difference between placebo and rolapitant was no greater than 1.7 milliseconds, suggesting an insignificant change in QTc with rolapitant. Rolapitant is safe and does not prolong the QT interval at doses up to 720 mg relative to placebo in healthy adults.

Effects of rolapitant administered orally on the pharmacokinetics of dextromethorphan (CYP2D6), tolbutamide (CYP2C9), omeprazole (CYP2C19), efavirenz (CYP2B6), and repaglinide (CYP2C8) in healthy subjects.

PURPOSE: Rolapitant is a neurokinin-1 receptor antagonist indicated in combination with other antiemetic agents in adults for the prevention of delayed chemotherapy-induced nausea and vomiting. We evaluated the effects of rolapitant oral on the pharmacokinetics of probe substrates for cytochrome P450 (CYP) 2D6 (dextromethorphan), 2C9 (tolbutamide), 2C19 (omeprazole), 2B6 (efavirenz), and 2C8 (repaglinide) in healthy subjects. METHODS: This open-label, multipart, randomized, phase 1 study assessed cohorts of 20-26 healthy subjects administered dextromethorphan, tolbutamide plus omeprazole, efavirenz, or repaglinide with and without single, oral doses of rolapitant. Maximum plasma analyte concentrations (Cmax) and area under the plasma analyte concentration-time curves (AUC) were estimated using noncompartmental analysis, and geometric mean ratios (GMRs) and 90% confidence intervals for the ratios of test (rolapitant plus probe substrate) to reference (probe substrate alone) treatment were calculated. RESULTS: Rolapitant significantly increased the systemic exposure of dextromethorphan in terms of Cmax and AUC0-inf by 2.2- to 3.3-fold as observed in GMRs on days 7 and 14. Rolapitant did not affect systemic exposure of tolbutamide, and minor excursions outside of the 80-125% no effect limits were detected for omeprazole, efavirenz, and repaglinide. CONCLUSIONS: Inhibition of dextromethorphan by a single oral dose of rolapitant 180 mg is clinically significant and can last at least 7 days. No clinically significant interaction was observed between rolapitant and substrates of CYP2C9, CYP2C19, CYP2B6, or CYP2C8. CYP2D6 substrate drugs with a narrow therapeutic index may require monitoring for adverse reactions if given concomitantly with rolapitant.

Absorption, metabolism, and excretion of the antiemetic rolapitant, a selective neurokinin-1 receptor antagonist, in healthy male subjects.

Rolapitant is a neurokinin-1 receptor antagonist that is approved in combination with other antiemetic agents in adults for the prevention of delayed nausea and vomiting (CINV) associated with initial and repeat courses of emetogenic cancer chemotherapy, including but not limited to highly emetogenic chemotherapy. Here, we assessed the absorption, metabolism, and excretion of 14C-labeled rolapitant in healthy male subjects. Rolapitant was administered as a single 180-mg oral dose containing approximately 100 µCi of total radioactivity, with plasma, urine, and fecal samples collected at defined intervals after dosing. Rolapitant had a large apparent volume of distribution, indicating that it is widely distributed into body tissues. Rolapitant was slowly metabolized and eliminated with a mean half-life of 186 h. Exposure to the major metabolite of rolapitant, C4-pyrrolidinyl hydroxylated rolapitant or M19, was approximately 50% of rolapitant exposure in plasma. Renal clearance was not a significant elimination route for rolapitant-related entities. Total radioactivity recovered in urine accounted for 14.2% of the dose, compared to 72.7% recovery in feces. Adverse events (AEs) were generally mild; there were no serious AEs, and no clinically significant changes in laboratory or electrocardiogram parameters were observed. The combination of rolapitant safety, its long half-life, extensive tissue distribution, and slow elimination via the hepatobiliary route (rather than renal excretion) suggest suitability that a single dose of rolapitant may provide protection against CINV beyond the first 24 h after chemotherapy administration.

Characterization of the ß-defensin genes in giant panda.

ß-Defensins are small antimicrobial proteins expressed in various organisms and have great potential for improving animal health and selective breeding programs. Giant pandas have a distinctive lineage in Carnivora, and it is unclear whether ß-defensin genes have experienced different selective pressures during giant panda evolution. We therefore characterized the giant panda (Ailuropoda melanoleuca) ß-defensin gene family through gap filling, TBLASTN, and HMM searches. Among 36 ß-defensins identified, gastrointestinal disease may induce the expression of the DEFB1 and DEFB139 genes in the digestive system. Moreover, for DEFB139, a significant positive selection different from that of its homologs was revealed through branch model comparisons. A Pro-to-Arg mutation in the giant panda DEFB139 mature peptide may have enhanced the peptide's antimicrobial potency by increasing its stability, isoelectric point, surface charge and surface hydrophobicity, and by stabilizing its second ß-sheet. Broth microdilution tests showed that the increase in net charge caused by the Pro-to-Arg mutation has enhanced the peptide's potency against Staphylococcus aureus, although the increase was minor. We expect that additional gene function and expression studies of the giant panda DEFB139 gene could improve the existing conservation strategies for the giant panda.