Integrating Full Bayesian Inference and Student's t-Distribution Method for Enhanced Outlier Handling in Caffeine Population Pharmacokinetics: Assessing Drug-Drug Interactions with Enasidenib in Relapsed or Refractory AML and MDS Patients.

As the first-in-class, selective, and potent inhibitor of the isocitrate dehydrogenase-2 (IDH2) mutant protein, enasidenib was approved by the US Food and Drug Administration (FDA) in 2017 for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with an IDH2 mutation. Known for its interactions with various cytochrome P450 (CYP) enzymes and transporters in vitro, a clinical pharmacokinetics (PK) trial was initiated to assess the impact of multiple doses of enasidenib on the single-dose PK of sensitive probe substrates of several cytochrome P450 enzymes and transporters. In this study, a population pharmacokinetic analysis approach was employed to address challenges posed by high, nonzero baseline caffeine concentrations. Moreover, we integrated full Bayesian inference into this approach innovatively for a more detailed understanding of parameter uncertainty and greater modeling flexibility, alongside Student's t-distribution for robust error modeling in handling the abnormal outlier caffeine concentration data observed in this trial. Our analyses demonstrated that multiple doses of enasidenib altered caffeine clearance to a clinically meaningful extent, as evidenced by an approximate 8-fold decrease. This finding led to a specific recommendation in the package insert to avoid the concurrent use of certain CYP1A2 substrates with enasidenib, unless directed otherwise in the prescribing information. Furthermore, this research underlines the technical benefits of integrating full Bayesian inference and incorporating Student's t-distribution for residual error modeling in the PK field.

Pediatric model-based dose optimization using a pooled exposure-response safety analysis for nivolumab and nivolumab plus ipilimumab combination in melanoma.

An exposure-response (E-R) safety analysis was conducted across adult and pediatric (<18 years) studies to evaluate the potential impact of higher nivolumab and/or ipilimumab exposures in adolescents (≥12 to <18 years) versus adults with melanoma using the approved adult dosing regimens for nivolumab alone or in combination with ipilimumab. Data from 3507 patients across 15 studies were used to examine the relationship between nivolumab-ipilimumab daily average exposure and time to grade 2+ immune-mediated adverse events (gr2+ IMAEs). Results from the E-R safety model showed ipilimumab, but not nivolumab, exposure to be a statistically significant predictor of gr2+ IMAEs. Significant covariates included sex (41% higher risk for women than men), line of therapy (19% higher for first-line than later-line), and treatment setting (26% lower for adjuvant than advanced melanoma). Younger age and lower body weight (BW) were each associated with a lower risk of gr2+ IMAEs (hazard ratio [HR]: 0.830 for 15-year-olds versus 60-year-olds and 0.84 for BW 52 kg versus 75 kg). For adolescents with melanoma treated with nivolumab in the advanced or adjuvant settings, these results are supportive of nivolumab flat dosing regimens for adolescents greater than or equal to 40 kg and BW-based dosing for adolescents less than 40 kg. These results also support adult weight-based dosing regimens for nivolumab plus ipilimumab in adolescents with advanced melanoma. This analysis suggests that although higher exposures are predicted in adolescents with lower weight compared with adults, there is no predicted immune-mediated safety risk when treated with the approved adult dosing of nivolumab with/without ipilimumab.

Nivolumab and ipilimumab population pharmacokinetics in support of pediatric dose recommendations-Going beyond the body-size effect.

Body size has historically been considered the primary source of difference in the pharmacokinetics (PKs) of monoclonal antibodies (mAbs) between children aged greater than or equal to 2 years and adults. The contribution of age-associated differences (e.g., ontogeny) beyond body-size differences in the pediatric PKs of mAbs has not been comprehensively evaluated. In this study, the population PK of two mAbs (nivolumab and ipilimumab) in pediatric oncology patients were characterized. The effects of age-related covariates on nivolumab or ipilimumab PKs were assessed using data from 13 and 10 clinical studies, respectively, across multiple tumor types, including melanoma, lymphoma, central nervous system tumors (CNSTs), and other solid tumors. Clearance was lower in pediatric patients (aged 1-17 years) with solid tumors or CNST than in adults after adjusting for other covariates, including the effect of body size. In contrast, clearance was similar in pediatric patients with lymphoma to that in adults with lymphoma. The pediatric effects characterized have increased the accuracy of the predictions of the model, facilitating its use in subsequent exposure comparisons between pediatric and adult patients, as well as for exposure-response analyses to inform pediatric dosing. This study approach may be applicable to the optimization of pediatric dosing of other mAbs and possibly other biologics.

Cord-Blood Engraftment Using an Enhanced Dual-Conditioning Regimen for Malignant Hematologic Diseases.

To explore a more effective conditioning regimen for umbilical cord blood transplantation (UCBT) to treat hematologic malignancies, we conducted a cohort study of a fludarabine/busulfan/cytarabine plus cyclophosphamide 200 mg/kg regimen. Forty-two consecutive patients with leukemia, myelodysplastic syndrome, or lymphoma received the regimen. The median number of infused total nucleated cells per kilogram was 5.5 × 107 (1.81-20.6), the median number of infused CD34+ cells per kilogram was 1.58 × 105 (0.58-6.6), and the median follow-up for surviving patients was 37 months (4.0-79.5 months). The cumulative incidence of neutrophil engraftment at 31 days was 100% [95% confidence interval (CI): 0.9159-1.0], and the median time to neutrophil engraftment was 19 days. The cumulative incidence of nonrelapse mortality was 12.76% (95% CI: 0.0455-0.2356) at 180 days and 3 years. The 3-year overall survival (OS) and disease-free survival (DFS) rates were 71.6% and 59.6%, respectively. Especially in patients who received transplants in the early and intermediate stages, the 3-year OS and DFS rates were 90.3% (95% CI: 0.805-1.0) and 76.2% (95% CI: 0.608-0.956), respectively. The regimen significantly improved engraftment and survival, indicating that the high graft failure of UCBT was caused by rejection.

Sweritranslactone D, a hepatoprotective novel secoiridoid dimer with tetracyclic lactone skeleton from heat-transformed swertiamarin.

Swertia mileensis, known as Qing-Ye-Dan (QYD), has been documented in Chinese Pharmacopoeia to cure hepatitis. Interestingly, its announced main active component, swertiamarin, could not be detected in the decoction, which indicated that the efficacy of QYD might be attributed to heat-transformed products of swertiamarin (HTPS). Further investigation on HTPS led to the isolation of sweritranslactone D (1), a novel secoiridoid dimer possessing a tetracyclic lactone skeleton, with better hepatoprotective activity than N-acetyl-L-cysteine in vitro.

6-MOMIPP, a novel brain-penetrant anti-mitotic indolyl-chalcone, inhibits glioblastoma growth and viability.

PURPOSE: 3-(6-Methoxy-2-methyl-1H-indol-3-yl)-1-(4-pyridinyl)-2-propene-1-one (6-MOMIPP) is a novel indole-based chalcone that disrupts microtubules. The present study aims to define the mechanism through which 6-MOMIPP induces cell death and to evaluate the efficacy of the compound in penetrating the blood-brain barrier and inhibiting growth of glioblastoma xenografts. METHODS: The effects of 6-MOMIPP were evaluated in cultured U251 glioblastoma cells, using viability, flow cytometry, and tubulin polymerization assays. Scintillation proximity and tubulin crosslinking methods were used to identify the binding site of 6-MOMIPP on tubulin, and western blots were performed to define the signaling pathways that contribute to cell death. LC/MS assays were used to study the pharmacokinetic behavior of 6-MOMIPP in mice. Subcutaneous and intracerebral xenograft models were utilized to assess the effects of 6-MOMIPP on growth of U251 glioblastoma in vivo. RESULTS: The findings indicate that 6-MOMIPP targets the colchicine site on ß-tubulin. At concentrations ≥ 250 nm, 6-MOMIPP induces mitotic arrest, caspase activation and loss of cell viability. Cells are protected by caspase inhibitors, pointing to an apoptotic mechanism of cell death. Loss of cell viability is preceded by activation of Cdk1(Cdc2) and phosphorylation of Bcl-2 and Bcl-xL. Inhibition of both events with a Cdk1 inhibitor prevents cell death. 6-MOMIPP has broad activity against the viability of multiple glioblastoma, melanoma and lung carcinoma cell lines. Viability of normal cells, including differentiated neurons, is not significantly affected at a drug concentration (1 µM) that reduces viability in most cancer lines. Pharmacokinetic studies in mice show that concentrations of 6-MOMIPP in the brain mirror those in the plasma, indicating that 6-MOMIPP readily penetrates the blood-brain barrier. Studies with mice bearing human U251 glioblastoma xenografts demonstrate that 6-MOMIPP is effective in suppressing growth of subcutaneous and intracerebral tumors without causing general toxicity. CONCLUSIONS: The results indicate that 6-MOMIPP is a novel microtubule disruptor that targets the colchicine binding site on ß-tubulin to induce mitotic arrest and cell death. The ability of 6-MOMIPP to penetrate the blood-brain barrier and inhibit growth of glioblastoma xenografts suggests that it warrants further preclinical evaluation as potential small-molecule therapeutic that may have advantages in treating primary and metastatic brain tumors.

Differences in molecular regulation between osteochondroma and bizarre parosteal osteochondromatous proliferation.

The differences in molecular mechanisms between osteochondroma and bizarre parosteal osteochondromatous proliferation (BPOP) remain to be fully elucidated. In the present study, the differentially expressed genes between BPOP and osteochondroma were obtained from the Gene Expression Omnibus online database, and the associations among these genes were analyzed using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) online bioinformatics software. The results revealed several differentially expressed genes between human BPOP and osteochondroma. These differentially expressed genes were also enriched in different subgroups based on the analysis using DAVID online software, including 'transforming growth factor ß receptor signaling pathway', 'BMP signaling pathway', 'Wnt receptor signaling pathway', 'response to chemical stimulus', 'regulation of inflammatory response', 'response to stress', 'glycosaminoglycan binding', 'polysaccharide binding', 'extracellular matrix structural constituent' and 'growth factors binding'. Taken together, these findings led to the conclusion that different gene regulatory mechanisms exist between BPOP and osteochondroma. Environmental stimulation and inflammation may contribute to BPOP or osteochondroma, and differences in extracellular matrix may contribute to differences in biological characteristics between BPOP and osteochondroma.

Synthesis and biological evaluation of isomeric methoxy substitutions on anti-cancer indolyl-pyridinyl-propenones: Effects on potency and mode of activity.

Certain indolyl-pyridinyl-propenone analogues kill glioblastoma cells that have become resistant to conventional therapeutic drugs. Some of these analogues induce a novel form of non-apoptotic cell death called methuosis, while others primarily cause microtubule disruption. Ready access to 5-indole substitution has allowed characterization of this position to be important for both types of mechanisms when a simple methoxy group is present. We now report the syntheses and biological effects of isomeric methoxy substitutions on the indole ring. Additionally, analogues containing a trimethoxyphenyl group in place of the pyridinyl moiety were evaluated for anticancer activity. The results demonstrate that the location of the methoxy group can alter both the potency and the mechanism of cell death. Remarkably, changing the methoxy from the 5-position to the 6-position switched the biological activity from induction of methuosis to disruption of microtubules. The latter may represent a prototype for a new class of mitotic inhibitors with potential therapeutic utility.

Disruption of prostaglandin E2 receptor EP4 impairs urinary concentration via decreasing aquaporin 2 in renal collecting ducts.

The antidiuretic hormone arginine vasopressin is a systemic effector in urinary concentration. However, increasing evidence suggests that other locally produced factors may also play an important role in the regulation of water reabsorption in renal collecting ducts. Recently, prostaglandin E2 (PGE2) receptor EP4 has emerged as a potential therapeutic target for the treatment of nephrogenic diabetes insipidus, but the underlying mechanism is unknown. To evaluate the role of EP4 in regulating water homeostasis, mice with renal tubule-specific knockout of EP4 (Ksp-EP4(-/-)) and collecting duct-specific knockout of EP4 (AQP2-EP4(-/-)) were generated using the Cre-loxP recombination system. Urine concentrating defect was observed in both Ksp-EP4(-/-) and AQP2-EP4(-/-) mice. Decreased aquaporin 2 (AQP2) abundance and apical membrane targeting in renal collecting ducts were evident in Ksp-EP4(-/-) mice. In vitro studies demonstrated that AQP2 mRNA and protein levels were significantly up-regulated in mouse primary inner medullary collecting duct (IMCD) cells after pharmacological activation or adenovirus-mediated overexpression of EP4 in a cAMP/cAMP-response element binding protein-dependent manner. In addition, EP4 activation or overexpression also increased AQP2 membrane accumulation in a mouse IMCD cell line (IMCD3) stably transfected with the AQP2 gene, mainly through the cAMP/protein kinase A and extracellular signal-regulated kinase pathways. In summary, the EP4 receptor in renal collecting ducts plays an important role in regulating urinary concentration under physiological conditions. The ability of EP4 to promote AQP2 membrane targeting and increase AQP2 abundance makes it a potential therapeutic target for the treatment of clinical disorders including acquired and congenital diabetes insipidus.

FAM3A activates PI3K p110α/Akt signaling to ameliorate hepatic gluconeogenesis and lipogenesis.

UNLABELLED: FAM3A belongs to a novel cytokine-like gene family, and its physiological role remains largely unknown. In our study, we found a marked reduction of FAM3A expression in the livers of db/db and high-fat diet (HFD)-induced diabetic mice. Hepatic overexpression of FAM3A markedly attenuated hyperglycemia, insulin resistance, and fatty liver with increased Akt (pAkt) signaling and repressed gluconeogenesis and lipogenesis in the livers of those mice. In contrast, small interfering RNA (siRNA)-mediated knockdown of hepatic FAM3A resulted in hyperglycemia with reduced pAkt levels and increased gluconeogenesis and lipogenesis in the livers of C57BL/6 mice. In vitro study revealed that FAM3A was mainly localized in the mitochondria, where it increases adenosine triphosphate (ATP) production and secretion in cultured hepatocytes. FAM3A activated Akt through the p110α catalytic subunit of PI3K in an insulin-independent manner. Blockade of P2 ATP receptors or downstream phospholipase C (PLC) and IP3R and removal of medium calcium all significantly reduced FAM3A-induced increase in cytosolic free Ca(2+) levels and attenuated FAM3A-mediated PI3K/Akt activation. Moreover, FAM3A-induced Akt activation was completely abolished by the inhibition of calmodulin (CaM). CONCLUSION: FAM3A plays crucial roles in the regulation of glucose and lipid metabolism in the liver, where it activates the PI3K-Akt signaling pathway by way of a Ca(2+) /CaM-dependent mechanism. Up-regulating hepatic FAM3A expression may represent an attractive means for the treatment of insulin resistance, type 2 diabetes, and nonalcoholic fatty liver disease (NAFLD).

Metformin induces renal medullary interstitial cell apoptosis in type 2 diabetic mice.

OBJECTIVE: Metformin is a first-line antidiabetic drug for type 2 diabetes (T2D) with a relatively good safety profile. Metformin activates AMP-activated protein kinase (AMPK), which is crucial in maintaining renal medullary function, with inappropriate AMPK activation facilitating renal medullary interstitial cells (RMICs) apoptosis under hypertonic challenge. The present study was to determine the effects of metformin on RMIC survival in both normal and T2D mice. METHODS: Mice (C57BL/6, db/m, and db/db) were treated with 450 mg/kg metformin for 7 days and subjected to 24-h water restriction (=dehydration) before being killed. Cell apoptosis in the renal medulla was determined by the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) assay. Cultured RMIC were treated with 10 mmol/L metformin in the presence or absence of hypertonic stress. Cell viability was determined and the underlying mechanisms were investigated. RESULTS: Metformin induced significant apoptosis of RMIC in dehydrated normal mice and both hydrated and dehydrated T2D mice. Hypertonicity increased ATP production and inhibited AMPK phosphorylation in RMIC, which was attenuated by metformin. Metformin augmented hypertonicity-induced apoptosis of RMIC, suppressed the nuclear factor-κB/cyclo-oxygenase-2 pathway, reduced reactive oxygen species production and inhibited transcriptional activation of tonicity-responsive enhancer binding protein (TonEBP) and its downstream osmoprotective gene expression. CONCLUSIONS: Metformin treatment is associated with increased RMIC apoptosis in both normally hydrated and dehydrated T2D mice. The results confirm AMPK as a critical factor involved in the maintenance of RMIC viability in T2D and raise safety concerns for metformin and other AMPK-activating antidiabetic drugs in dehydrated diabetic patients.