Pharmacokinetic-toxicodynamic Modeling to Elucidate the Involvement of Dorsal Root Ganglion Neuron in Oxaliplatin-induced Peripheral Neuropathy

BACKGROUND/AIM

Oxaliplatin (L-OHP)-induced peripheral neuropathy (OIPN) limits L-OHP dosage due to nerve cell damage in the dorsal root ganglion (DRG) caused by platinum (Pt). Despite various recommended approaches for OIPN management, no effective approach has been established. The aim of this study was to evaluate Pt distribution into DRG after repeat administrations of L-OHP in rats and to develop a pharmacokinetic-toxicodynamic (PK-TD) model using Pt concentrations in DRG to predict neuropathy severity.

MATERIALS AND METHODS

Male Wistar rats were administered L-OHP (3, 5, or 8 mg/kg i.v.) once weekly. Blood and DRG samples were collected following L-OHP administration. For toxicodynamic (TD) study, OIPN was evaluated using the von Frey test. Plasma and DRG Pt concentrations and thresholds values in von Frey test were used for PK-TD modeling using Phoenix WinNonlin® version 8.3 software.

RESULTS

Pt concentration in the DRG increased with repeated administration of L-OHP in a dose-dependent manner, indicating Pt accumulation in DRG following multiple administrations. The PK-TD model, consisting of an indirect response model and a transit compartment model with the DRG compartment, adequately described the temporal changes in OIPN with reliable TD parameters (≤36.4% with coefficient of variation). The maximum drug inhibition model could be employed to establish a quantitative correlation between the Pt content present in the DRG and the toxic potency resulting in OIPN.

CONCLUSION

The utility of the PK-TD model for predicting neuropathy outcomes was established, suggesting that models composed of the DRG compartment contribute to determining an optimal dosing strategy for reducing OIPN.

Pharmacokinetic evaluation of oxaliplatin combined with S-1 (SOX) chemotherapy in a rat model of colorectal cancer with acute kidney injury: predictive renal biomarkers for dose optimisation

Dose adjustment based on renal function is essential in S-1, which contains the 5‑fluorouracil prodrug tegafur, and platinum-based agent oxaliplatin (SOX) combination chemotherapy for colorectal cancer in patients with chronic kidney disease. However, limited evidence on dose adjustment in acute kidney injury (AKI) and challenges in determining dosing strategies. This study investigated the pharmacokinetics of SOX chemotherapy and renal biomarkers in rats.AKI was prepared by renal ischaemia-reperfusion injury in 1,2-dimethylhydrazine-induced colorectal cancer model rats. Serum creatinine (sCr) levels were determined as a renal biomarker. After administration of S-1 (2 mg/kg tegafur) and oxaliplatin (5 mg/kg), drug concentrations of tegafur, 5-FU, and platinum were measured in the plasma and tumours.No alterations in the area under the plasma concentration-time curve (AUC0-24h) values of 5-fluorouracil were observed between control and AKI model rats. The tumour concentrations of 5-fluorouracil in the mild and severe AKI groups were significantly lower than control group. The AUC0-24h for platinum increased with AKI severity. Notably, population pharmacokinetic analysis identified sCr as a covariate in platinum distribution after SOX chemotherapy.To optimise dose adjustment of SOX chemotherapy in patients with AKI, sCr may be a key factor in determining the appropriate dose.

Comparing the pharmacokinetics and organ/tissue distribution of anti-methicillin-resistant Staphylococcus aureus agents using a rat model of sepsis

Sepsis is a major cause of death, and sepsis-derived physiological changes complicate the understanding of drug distribution in organs/tissues, which determines the efficacy and toxicity of antimicrobial agents. In this study, we evaluated and compared the pharmacokinetics of methicillin-resistant Staphylococcus aureus treatment agents in sepsis with that of vancomycin, arbekacin, linezolid, and daptomycin.Rat models of sepsis were prepared using cecal ligation puncture. The pharmacokinetics of vancomycin, arbekacin, linezolid, and daptomycin were evaluated using their drug concentration profiles in plasma, kidneys, liver, lungs, skin, and muscles after intravenous administration in normal and septic rats.The kidney/plasma concentration ratio was higher in septic rats than in normal rats for vancomycin, arbekacin, and daptomycin but not for linezolid. The increase in the kidney/plasma concentration ratio for vancomycin was time-dependent, indicating an association between sepsis and stasis of vancomycin in the kidneys. In contrast, the distribution of linezolid from the blood to the organs/tissues in septic rats was comparable to that in normal rats.Sepsis-induced nephrotoxicity results in the stasis of vancomycin in the kidney, suggesting that this exacerbates proximal tubular epithelial cell injury. No dose modification of linezolid may be required for patients with sepsis.

Assessment of drug-drug interaction and optimization in capecitabine and irinotecan combination regimen using a physiologically based pharmacokinetic model

Capecitabine and irinotecan (CPT-11) combination regimen (XELIRI) is used for colorectal cancer treatment. Capecitabine is metabolized to 5-fluorouracil (5-FU) by three enzymes, including carboxylesterase (CES). CES can also convert CPT-11 to 7-ethyl-10-hydroxycamptotecin (SN-38). CES is involved in the metabolic activation of both capecitabine and CPT-11, and it is possible that drug-drug interactions occur in XELIRI. Here, a physiologically based pharmacokinetic (PBPK) model was developed to evaluate drug-drug interactions. Capecitabine (180 mg/kg) and CPT-11 (180 mg/m²) were administered to rats, and blood (250 μL) was collected from the jugular vein nine times after administration. Metabolic enzyme activities and K_i values were calculated through in vitro experiments. The plasma concentration of 5-FU in XELIRI was significantly decreased compared to capecitabine monotherapy, and metabolism of capecitabine by CES was inhibited by CPT-11. A PBPK model was developed based on the in vivo and in vitro results. Furthermore, a PBPK model-based simulation was performed with the capecitabin dose ranging from 0 to 1000mol/kg in XELIRI, and it was found that an approximately 1.7-fold dosage of capecitabine was required in XELIRI for comparable 5-FU exposure with capecitabine monotherapy. PBPK model-based simulation will contribute to the optimization of colorectal cancer chemotherapy using XELIRI.

Safety, efficacy, and analysis of key parameters after prophylactic administration of a sustained-release formulation of azithromycin in lung cancer surgery

BACKGROUND

The current use of prophylactic antibiotics for lung cancer surgery requires modification in aging individuals with impaired lung function. A sustained-release formulation of azithromycin (AZM-SR) could help resolve some of these challenges with its sustained antibacterial and anti-inflammatory effects. The aim of this study was to examine the safety and efficacy of AZM-SR in lung cancer surgery as well as its anti-inflammatory effect.

METHODS

Fifty patients were included in the study, and AZM-SR was administered 1 day prior to the surgery. The clinical course, including postoperative complications, was monitored, and the concentration of AZM, bacterial culture, and inflammatory cytokine levels of resected lung specimens were evaluated.

RESULTS

No side effects related to AZM-SR were observed. Five cases of postoperative pneumonia (10%) were observed; technical issues were involved in 3 cases. All patients recovered well. Four cases showed positive bacterial culture upon lung tissue examination; however, this was not significantly correlated with postoperative complications. A negative correlation was observed between AZM concentration in lung tissue and interleukin-6 (IL-6) expression.

CONCLUSIONS

Prophylactic utilization of AZM-SR in lung cancer surgery seems feasible. The anti-inflammatory effect of AZM might contribute additional beneficial effects in the perioperative management of lung cancer surgery.

A Physiologically Based Pharmacokinetic-Pharmacodynamic Model for Capecitabine in Colorectal Cancer Rats: Simulation of Antitumor Efficacy at Various Administration Schedules

BACKGROUND AND OBJECTIVES

Capecitabine is an oral prodrug of 5-fluorouracil and is widely used for colorectal cancer (CRC) treatment. However, knowledge of its antitumor efficacy after modification of the dosing schedule is insufficient. The aim of this study was to predict the antitumor efficacy of capecitabine using a physiologically based pharmacokinetic-pharmacodynamic (PBPK-PD) model based on metabolic enzyme activities.

METHODS

CRC model rats were administrated 180 mg/kg of capecitabine for 2 weeks. Blood samples were collected at 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, and 8 h following capecitabine administration. Plasma concentrations of capecitabine and its metabolites were measured on days 1, 7, and 14. Metabolic enzyme activities were determined in vitro using the liver and small intestine of the CRC model rats. A PBPK-PD model was developed based on metabolic enzyme activities. The antitumor efficacy of capecitabine after regimen modification was simulated using the PBPK-PD model.

RESULTS

Capecitabine antitumor efficacy was dose-dependent. A dose of > 500 μmol/kg was needed to inhibit tumor growth. After capecitabine regimen modification, a 1-week postponement of capecitabine administration was more efficacious than a reduction in the dosage to 80%.

CONCLUSIONS

The PBPK-PD model could simulate the antitumor efficacy at various capecitabine administration schedules. PBPK-PD models can contribute to the development of an appropriate CRC chemotherapy regimen with capecitabine.

Comparison of In Vivo Transportability of Anti-Methicillin-Resistant Staphylococcus aureus (MRSA) Agents Into Intracellular and Extracellular Tissue Spaces in Rats

The pathogenic bacterium Staphylococcus aureus can penetrate host cells. However, intracellular S. aureus is not considered during antimicrobial agent selection in clinical chemotherapy because of the lack of information about drug transportability into cells in vivo. We focused on agents used to treat methicillin-resistant S. aureus (MRSA) (vancomycin, arbekacin, linezolid, and daptomycin) and indirectly assessed the drug levels in intracellular compartment using plasma, tissue homogenates, and interstitial fluid (ISF) samples from the skin of rats using the microneedle array technique. Lower drug levels were observed in the ISF than in the plasma for daptomycin but extracellular and intracellular drug levels were comparable. In contrast, vancomycin, arbekacin, and linezolid showed higher concentrations in the ISF than in the plasma. Intracellular transport was estimated only for arbekacin. Stasis of vancomycin in the ISF was also observed. These results suggest that both low vancomycin exposure against intracellular S. aureus infection and long-term subinhibitory drug levels in the ISF contribute to the failure of treatment and emergence of antibiotic resistance. Based on its pharmacokinetic characteristics in niche extravascular tissue spaces, arbekacin may be suitable for achieving sufficient clinical outcomes for MRSA infection because the drug is widely distributed in extracellular and intracellular compartments.

Pharmacokinetics of Macrolide Antibiotics and Transport into the Interstitial Fluid: Comparison among Erythromycin, Clarithromycin, and Azithromycin

Recent research has found higher levels and longer total exposure of azithromycin, a macrolide antibiotic agent, in the interstitial fluid of the skin than in the plasma. This unique distribution is expected to contribute to its antimicrobial activity at the primary infection site. However, it remains unclear whether this characteristic distribution in the extracellular tissue space is common to macrolide antibiotics or if it is azithromycin-specific, with most macrolides largely localized intracellularly. In this study, we investigated pharmacokinetic characteristics of erythromycin and clarithromycin in the interstitial fluid of the skin of rats after intravenous drug administration, and compared the results with our previously reported results on azithromycin. Interstitial fluid samples were directly collected from a pore on the skin using a dissolving microneedle array. We found that the total macrolide concentrations in the interstitial fluid were significantly different among three macrolides. The rank order of the interstitial fluid-plasma concentration ratio was azithromycin (3.8 to 4.9) > clarithromycin (1.2 to 1.5) > erythromycin (0.27 to 0.39), and this ratio was stable after dosing, whereas higher drug levels in the skin tissue than in the plasma were observed for all three macrolides. Our results suggest that lower erythromycin concentrations in the interstitial fluid than in the plasma contributes to the emergence of bacterial resistance in the extracellular tissue space. Monitoring of total macrolide concentrations in interstitial fluid may provide valuable information regarding antimicrobial effects and the emergence of bacterial resistance for the development of an appropriate pharmacokinetics-pharmacodynamics-based dosing strategy.

Population Pharmacokinetic Model-Based Evaluation of Circadian Variations in Plasma 5-Fluorouracil Concentrations During Long-Term Infusion in Rats: A Comparison With Oral Anticancer Prodrugs

Circadian fluctuations in the plasma concentration of 5-fluorouracil impede the accurate estimation of target therapeutic concentrations in the long-term infusion or oral 5-fluorouracil-based prodrug regimen. We evaluated the circadian patterns of plasma 5-fluorouracil concentrations in rats using population pharmacokinetic model. Rats were divided into 2 groups, and a continuous infusion (50 mg/m²/h) for 48 h was initiated with or without a bolus injection of 60 mg/kg 5-fluorouracil. In the group not administered a loading dose, significant circadian variation of plasma 5-fluorouracil concentration was observed. In contrast, in the loading dose group, this circadian variation disappeared. Additionally, decreased hepatic dihydropyrimidine dehydrogenase activity was observed. Population model analysis revealed that the concentrations of 5-fluorouracil followed a 24-h cosine circadian curve, representing an overall 1.8-fold increase from a nadir to a peak, with a relative amplitude (% of mesor) of 28%. The circadian 5-fluorouracil clearance pattern in the infusion-regimen was consistent with previously reported pattern for capecitabine and uracil-tegafur. In the recently modified regimen omitting the bolus injection of 5-fluorouracil, the circadian variations should be considered for blood sampling time points in therapeutic drug monitoring. The chronomodulated chemotherapy using oral prodrug administration could be established based on accumulating evidence in the infusion-regimen.

Assessment of pharmacokinetic variations of capecitabine after multiple administration in rats: a physiologically based pharmacokinetic model

PURPOSE

Capecitabine is a prodrug of 5-fluorouracil (5-FU) used for the treatment of colorectal cancer, with a two-week course of administration. However, the variance in plasma concentration and metabolic enzyme activities after multiple administration of capecitabine and its metabolites is unknown. The aim of this study was to identify the variance and predict the plasma concentration profile of capecitabine and its metabolites, using metabolic enzyme activities, to develop a more effective and safer medication.

METHODS

Rats orally received 180 mg/kg of capecitabine once a day for two weeks. Blood samples were collected nine times, and plasma concentration was measured on day 1, 7, and 14. The liver and small intestine were removed after blood sampling and were used in vitro to evaluate metabolic enzyme activities of carboxylesterase, cytidine deaminase, and thymidine phosphorylase. A physiologically based pharmacokinetic (PBPK) model was developed using in vitro results.

RESULTS

Area under the plasma concentration-time curve from 0 h to infinity of 5-FU on day 7 and day 14 was significantly lower than that on day 1. Intrinsic clearance of thymidine phosphorylase in the liver on day 7 and day 14 was 1.4 and 1.3 times lower than that on day 1, respectively. The PBPK model described the observed plasma concentration of capecitabine and its metabolites.

CONCLUSION

The decreased plasma concentration of capecitabine was caused by decreased metabolic enzyme activity. Efficacy can be improved by dose adjustment of capecitabine based on metabolic enzyme activities, using the PBPK model.

Population pharmacokinetics of afatinib and exposure-safety relationships in Japanese patients with EGFR mutation-positive non-small cell lung cancer

To investigate the exposure–safety relationships of afatinib in Japanese population, we performed population pharmacokinetics (PK) analysis of afatinib in Japanese advanced non-small cell lung cancer patients harboring epidermal growth factor receptor mutation. Plasma samples were collected at 0.5–1, 2–3, 8–12, and 24 h after oral afatinib (40 mg) administration on day 1 and day 8. Plasma afatinib concentrations were determined using high-performance liquid chromatography. Data was analyzed following the population approach and using the software Phoenix^® NLME^TM Version 7.0 software (Certara USA, Inc., Princeton, NJ, USA). From 34 patients, a total of 354 afatinib plasma concentration values were available for the population PK analysis. Significant covariates in the population PK model included aspartate aminotransferase and creatinine clearance on CL/F, and age and body mass index on V/F. Results of simulation based on final PK model indicated that hepatic impairment had a significant effect on afatinib levels in plasma after multiple dosing. Afatinib trough plasma concentrations on day 8 were higher in patients with adverse events of grade 3 or higher. The population PK analysis showed that hepatic impairment affected afatinib PK parameters and contributed to the high inter-patient variability and high plasma concentrations of afatinib following multiple treatments.

Circadian variations in the pharmacokinetics of the oral anticancer agent tegafur-uracil (UFT) and its metabolites in rats

Uracil-tegafur (UFT) is an oral anticancer drug containing uracil and 5‑fluorouracil prodrug tegafur and is widely used for adjuvant chemotherapy of colorectal cancer. Although clinical data show circadian variations in plasma 5‑fluorouracil concentrations during its long-term infusion, and feasibility studies of chronomodulated administration have been previously reported, the circadian pattern in plasma 5‑fluorouracil concentration after UFT administrations remains unclear. The aim of this study was to identify factors causing circadian variations in UFT pharmacokinetics and estimate circadian patterns of plasma 5‑fluorouracil concentration corresponding to UFT dosing time in rats. Rats were orally administered UFT (15 mg/kg as tegafur) at three different times of the day: 07:00 (23 h after light onset, HALO), 13:00 (5 HALO), or 19:00 (11 HALO), and then plasma concentrations of tegafur, 5‑fluorouracil, and uracil were measured after UFT administration. We found that the area under the plasma concentration-time curves (AUC_0-∞) of 5‑fluorouracil depended on the UFT dosing time of day with a 2.4-fold difference between the peak (at 19:00: 13.7 ± 1.4 μmol·h/L) and trough (at 13:00: 5.6 ± 1.3 μmol·h/L). The simulated population mean clearance of 5‑fluorouracil followed a 24-h cosine circadian curve, with the highest value in the early light phase being 2.2-fold higher than the lowest value in the early dark phase, which was an inverse circadian pattern compared to the plasma 5‑fluorouracil concentration. The plasma tegafur levels suggested that circadian variation in tegafur absorption and conversion to 5‑fluorouracil are factors causing variations in plasma 5‑fluorouracil levels following UFT administration. In conclusion, the circadian pattern of 5‑fluorouracil clearance and circadian variations in tegafur pharmacokinetics are important determinants of plasma 5‑fluorouracil concentrations following UFT administration. This knowledge could help in developing a chronomodulated administration strategy of UFT for improving clinical outcomes.

Susceptibility to serious skin and subcutaneous tissue disorders and skin tissue distribution of sodium-dependent glucose co-transporter type 2 (SGLT2) inhibitors

Objectives: In Japan, sodium-glucose co-transporter type 2 (SGLT2) inhibitors have been reported to be associated with serious skin and subcutaneous tissue disorders. A post-marketing surveillance (PMS) study suggested that the association was specific for ipragliflozin and, to a lesser extent for dapagliflozin. These studies were performed to confirm the association of 6 SGLT2 inhibitors with serious skin disorders in a clinical setting, to elucidate the role of melanin in serious skin disorders and to understand the underlying mechanisms. Methods: The latest PMS records were retrieved from the Japanese Adverse Drug Event Report (JADER) database, and the associations were analyzed by data mining techniques. In silico 3-D docking simulation of SGLT2 inhibitors with melanin was performed using the MOE software. The skin tissue distribution of SGLT2 inhibitors was evaluated using albino rats after oral administration at clinical doses. Results: The adjusted reporting odds ratio (95% confidential limit) was 1.667 (1.415, 1.963) for ipragliflozin, 0.514 (0.317, 0.835) for dapagliflozin, 0.149 (0.048, 0.465) for tofogliflozin, 0.624 (0.331, 1.177) for luseogliflozin, 0.590 (0.277, 1.257) for canagliflozin and 0.293 (0.073, 1.187) for empagliflozin, when drugs other than the SGLT2 inhibitors were referred, and the association was detected only for ipragliflozin in clinical use. In silico 3-D docking simulation suggested the influence of melanin in ipragliflozin-specific serious skin disorders. The skin tissue-to-plasma concentration ratio of ipragliflozin was 0.45 ± 0.20 (±SD) at 1 hr after administration and increased in a time-dependent manner to 5.82 ± 3.66 at 24 hr (p<0.05), but not in case of other SGLT2 inhibitors. Conclusions: Serious skin disorders were suggested to be specific for ipragliflozin. Interaction with melanin might be implicated in ipragliflozin-specific serious skin disorders. Ipragliflozin was retained in the skin tissue, which suggested its interaction with the skin tissue in serious skin disorders.

Co-precipitation molecules hemopexin and transferrin may be key molecules for fibrillogenesis in TTR V30M amyloidogenesis

The disease model of familial amyloidotic polyneuropathy—7.2-hMet30 mice—manifests amyloid deposition that consists of a human amyloidogenic mutant transthyretin (TTR) (TTR V30M). Our previous study found amyloid deposits in 14 of 27 7.2-hMet30 mice at 21–24 months of age. In addition, non-fibrillar TTR deposits were found in amyloid-negative 7.2hMet30 mice. These results suggested that TTR amyloidogenesis required not only mutant TTR but also an additional factor (or factors) as an etiologic molecule. To determine the differences in serum proteome in amyloid-positive and amyloid-negative mice in the 7.2-hMet30 model, we used proteomic analyses and studied serum samples obtained from these mice. Hemopexin (HPX) and transferrin (Tf) were detected in the serum samples from amyloid-positive mice and were also found in amyloid deposits via immunohistochemistry, but serum samples from amyloid-negative mice did not contain HPX and Tf. These two proteins were also not detected in non-fibrillar TTR deposits. In addition, in silico analyses suggested that HPX and Tf facilitate destabilization of TTR secondary structures and misfolding of TTR. These results suggest that HPX and Tf may be associated with TTR amyloidogenesis after fibrillogenesis in vivo.

Circadian variations in the pharmacokinetics of capecitabine and its metabolites in rats

Capecitabine, an orally available prodrug of 5-fluorouracil, is widely used to treat patients with colorectal cancer. Although various studies have shown circadian variations in plasma 5-fluorouracil concentrations during long-term infusion, it is still unknown whether circadian variations also exist following administration of capecitabine. The present study aimed to investigate whether the pharmacokinetics of capecitabine and its metabolites, including 5-fluorouracil, vary according to administration time in rats. Rats were orally administered capecitabine (180mg/kg) at 07:00 (23h after light onset, HALO), 13:00 (5 HALO), or 19:00h (11 HALO). Plasma concentrations of capecitabine and its metabolites, such as 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouridine (5'-DFUR), and 5-fluorouracil, were determined after capecitabine administration. The results showed that the t_1/2 and AUC_0-∞ values of 5-fluorouracil differed as a function of the dosing time of capecitabine. The maximum and minimum mean t_1/2 values of 5-fluorouracil were obtained when the drug was administered at 07:00h (23 HALO: 3.1±1.2h) and 13:00h (5 HALO: 1.5±0.6h), respectively. The AUC_0-∞ value of 5-fluorouracil at 07:00h (23 HALO: 533.9±195.7μmol∙h/L) was 1.8-fold higher than the value at 13:00h (5 HALO: 302.5±157.1μmol∙h/L). The clearance of 5-fluorouracil followed a cosine circadian curve, and the simulated population mean clearance was highest at rest times and lowest during active times in rats. The results for the plasma 5'-DFCR and 5'-DFUR levels indicated that circadian variations in the sequential metabolism of capecitabine to 5-fluorouracil would also affect plasma 5-fluorouracil levels following capecitabine administration. In conclusion, the pharmacokinetics of capecitabine and its metabolites, including 5-fluorouracil, varied according to time of dosing, suggesting that the capecitabine administration time is an important factor in achieving sufficient efficacy and reducing toxicity in patients.

Dissolving Microneedles as Skin Allergy Test Device

The possibility of using dissolving microneedles (DMs) as a skin allergy test device was studied in rats. Poly-L-arginine was used as a model allergen. Dextran was used to prepare three kinds of DM array chips containing different doses of poly-L-arginine: 17.1±0.5 µg (low-dose DM), 42.2±0.8 µg (medium-dose DM), and 87.4±1.1 µg (high-dose DM); each 1.0 cm² chip contained 300 DMs. The mean lengths of the low-, medium-, and high-dose DM were 489±3, 485±3, and 492±1 µm and mean diameters of the base were 301±2, 299±1, and 299±2 µm, respectively. Furthermore, for the low-, medium-, and high-dose DM, the administered doses of poly-L-arginine were estimated to be 9.3±1.9, 31.1±1.3, and 61.9±4.7 µg and the scratching behavior per 30 min was 9.8±3.4, 60.4±8.3, and 95.7±10.6 times, respectively. These results demonstrate the dose dependence of the immunoreactivity of the poly-L-arginine DMs, suggesting that DMs can be used an alternative skin allergy device.

CSP-1103 (CHF5074) stabilizes human transthyretin in healthy human subjects

Hereditary amyloid polyneuropathy is a type of protein misfolding disease. Transthyretin (TTR) is a homotetrameric serum protein and TTR tetramer dissociation is the limiting step in amyloid fibril formation. Thus, prevention of TTR dissociation is a promising therapeutic approach and some TTR stabilizers have been approved for the treatment of TTR amyloidosis. CSP-1103 (CHF5074) is a non-steroidal anti-inflammatory derivative that lacks cyclooxygenase inhibitory activity. In vitro, CSP-1103 stabilizes the TTR tetramer by binding to the thyroxine (T4) binding site. We have previously shown that serum TTR levels were increased by oral CSP-1103 administration through stabilization of TTR tetramers in humanized mice at both the Ttr locus and the Rbp4 locus. To determine whether CSP-1103 stabilizes TTR tetramers in humans, multiple CSP-1103 oral doses were administered for two weeks to 48 healthy human volunteers in a double-blind, placebo-controlled, parallel-group study. CSP-1103 treatment stabilized TTR tetramers in a dose-dependent manner under normal or denaturing stress conditions, thereby increasing serum TTR levels. Preincubation of serum with CSP-1103 or diflunisal in vitro increased the TTR tetramer stability. Computer simulation analysis revealed that the binding affinities of CSP-1103 with TTR at pH 7.0 were similar to those of tafamidis, thus confirming that CSP-1103 has potent TTR-stabilizing activity.

Dissolving microneedles for enhanced local delivery of capsaicin to rat skin tissue

Capsaicin-loaded dissolving microneedles (DMNs) were prepared to investigate the analgesic effect of capsaicin on the skin. The dimensions of each microneedle (MN) were as follows: diameter of the basement, 17 mm; length, 500 μm; and width, 300 μm. The average capsaicin content in the DMNs loaded with a low and high dose of capsaicin was 8.8 ± 0.5 mg and 12.5 ± 0.4 mg. Almost all the capsaicin, 99.3 ± 4.1% and 99.7 ± 2.2% for low-dose and high-dose DMNs were released within 20 min. High amounts of capsaicin were recovered with 102.8 ± 0.1% of capsaicin after storage at 23 °C for 90 days. The pharmacological activity of capsaicin DMNs was compared to that of capsaicin cream as a positive control, by measuring the idiospasm of depilated rat skin. The time required to achieve 50% idiospasm suppression was 26.3 ± 1.9 min and 53.0 ± 2.3 min for low-dose and high-dose DMNs. A pharmacokinetic study showed high tissue capsaicin levels of 660.2 ± 120.6 and 1805.3 ± 218.1 μg/g wet weight for low-dose and high-dose DMNs at 5 min after administration. The results suggest that DMNs could exert a rapid local analgesic action on the skin.

Effects of a bolus injection of 5-fluorouracil on dihydropyrimidine dehydrogenase activity in rats receiving continuous infusion of 5-fluorouracil

PURPOSE

The options for improving the chemotherapeutic regimen consisting of bolus plus infusion of 5-fluorouracil (5-FU) include omitting the 5-FU bolus injection. We examined the effects of a 5-FU bolus injection on the activity of dihydropyrimidine dehydrogenase (DPD), which is the first and rate-limiting enzyme of 5-FU catabolism, in rats.

METHODS

The rats were divided into three groups, and then continuous infusion (50 mg/m(2)/h) for 4 h was started with a bolus injection of saline, 20 mg/kg 5-FU, or 60 mg/kg 5-FU. Plasma 5-FU, uracil (Ura), dihydrouracil (UH2) levels, and hepatic DPD activity were determined after administration of 5-FU.

RESULTS

The half-life after the end of the infusion (t 1/2, 4-8 h) of 5-FU in the rats given the bolus injection was significantly longer than in those that had been given saline, and it increased with increasing 5-FU bolus injection dosage (r = 0.801, p < 0.01). The plasma UH2/Ura ratio, an indirect biomarker of hepatic DPD activity, tended to be lower in the rats that had received a 5-FU bolus injection than in those that had not, and it remained low after infusion ended. The hepatic DPD activity in rats that had received a 5-FU bolus injection was significantly lower than in those that had not. Negative correlation was observed between DPD activity and bolus injection dosage (r = -0.691, p < 0.05).

CONCLUSIONS

A bolus injection suppresses hepatic DPD activity and its effects are dependent on dosage, resulting in slower elimination of 5-FU from the blood and contributing to long-term systemic exposure to 5-FU.

Lower Body Mass Index is a Risk Factor for In-Hospital Mortality of Elderly Japanese Patients Treated with Ampicillin/sulbactam

Objectives: A retrospective examination was conducted to identify risk factors for in-hospital mortality of elderly patients (65 years or older) treated with the beta-lactam/beta-lactamase inhibitor combination antibiotic, ampicillin/sulbactam (ABPC/SBT). Methods: Clinical data from 96 patients who were hospitalized with infectious diseases and treated with ABPC/SBT (9 g/day or 12 g/day) were analyzed. Risk factors examined included demographic and clinical laboratory parameters. Parameter values prior to treatment and changes after treatment were compared between survivors and non-survivors. Results: The study patients had an average age of 81.9±8.4 years (±SD) and body mass index (BMI) of 19.9±4.2 kg/m². They were characterized by anemia (low hemoglobin and hematocrit levels), inflammation (high leukocyte count, neutrophil count, C-reactive protein level, and body temperature), and hepatic and renal dysfunction (high aspartate aminotransferase, alanine aminotransferase and blood urea nitrogen levels). The BMI of non-survivors, 16.2±2.9 kg/m², was lower than that of survivors, 20.4±4.1 kg/m². In addition, the hematological parameters deteriorated more remarkably, inflammation markers were not altered (or the decrease was marginal), and hepatic function was not improved, in non-survivors. Conclusions: A lower BMI value is a risk factor for in-hospital mortality of elderly patients treated with ABPC/SBT.

Therapeutic Drug Monitoring of Vancomycin in Dermal Interstitial Fluid Using Dissolving Microneedles

OBJECTIVE

To design an alternative painless method for vancomycin (VCM) monitoring by withdrawing interstitial fluid (ISF) the skin using dissolving microneedles (DMNs) and possibly replace the conventional clinical blood sampling method.

METHODS

Male Wistar rats were anesthetized with 50 mg/kg sodium pentobarbital. Vancomycin at 5 mg/mL in saline was intravenously administered via the jugular vein. ISF was collected from a formed pore at 15, 30, 45, 60, 75, 90, and 120 min after the DMNs was removed from the skin. In addition, 0.3 mL blood samples were collected from the left femoral vein.

RESULTS

The correlation between the plasma and ISF VCM concentrations was significantly strong (r = 0.676, p < 0.05). Microscopic observation of the skin after application of the DMNs demonstrated their safety as a device for sampling ISF.

CONCLUSION

A novel monitoring method for VCM was developed to painlessly determine concentrations in the ISF as opposed to blood sampling.

Antipsychotics-associated serious adverse events in children: an analysis of the FAERS database

OBJECTIVE

The reports submitted to the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) from 1997 to 2011 were reviewed to assess serious adverse events induced by the administration of antipsychotics to children.

METHODS

Following pre-processing of FAERS data by elimination of duplicated records as well as adjustments to standardize drug names, reports involving haloperidol, olanzapine, quetiapine, clozapine, ziprasidone, risperidone, and aripiprazole were analyzed in children (age 0-12). Signals in the data that signified a drug-associated adverse event were detected via quantitative data mining algorithms. The algorithms applied to this study include the empirical Bayes geometric mean, the reporting odds ratio, the proportional reporting ratio, and the information component of a Bayesian confidence propagation neural network. Neuroleptic malignant syndrome (NMS), QT prolongation, leukopenia, and suicide attempt were focused on as serious adverse events.

RESULTS

In regard to NMS, the signal scores for haloperidol and aripiprazole were greater than for other antipsychotics. Significant signals of the QT prolongation adverse event were detected only for ziprasidone and risperidone. With respect to leukopenia, the association with clozapine was noteworthy. In the case of suicide attempt, signals for haloperidol, olanzapine, quetiapine, risperidone, and aripiprazole were detected.

CONCLUSIONS

It was suggested that there is a level of diversity in the strength of the association between various first- and second-generation antipsychotics with associated serious adverse events, which possibly lead to fatal outcomes. We recommend that research be continued in order to gather a large variety and quantity of related information, and that both available and newly reported data be placed in the context of multiple medical viewpoints in order to lead to improved levels of care.

Pharmacokinetic-pharmacodynamic (PK-PD) modeling and simulation of 5-fluorouracil for erythropenia in rats

INTRODUCTION

The aim of the present study was to develop a simple pharmacokinetic-pharmacodynamic (PK-PD) model in rats that could predict the onset and degree of erythropenia, a severely toxic side effect that severely limits the use of the anticancer agent 5-fluorouracil (5-FU).

METHODS

Total erythrocyte counts, hemoglobin (Hb) concentrations, and hematocrit (Hct) levels were measured in rats following the intravenous bolus administration of 5-FU for 4 days in order to obtain data for an analysis of the PK-PD model. Our PK-PD model consisted of a two-compartment PK model, with two compartments for the PD model and nine structural PK-PD model parameters.

RESULTS

After the intravenous bolus administration of 5, 10, or 20 mg/kg of 5-FU to rats, absolute erythrocyte counts, Hb concentrations, and Hct levels transiently decreased, reached minimum levels on Days 7-14, and then returned to baseline levels. The nadir values (Cnadir) for rats treated with 5, 10, or 20 mg/kg of 5-FU were significantly decreased to approximately 79.4, 76.3, or 46.5% of the baseline value (Cbaseline) in erythrocyte counts, 86.3, 83.3, or 45.7% of Cbaseline in Hb concentrations, 88.6, 85.5, or 47.1% of Cbaseline in Hct levels, respectively. The PK-PD model effectively captured the features of erythropenia and Cnadir after 5-FU chemotherapy. This PK-PD model was successfully used to characterize the learner relationship between the area under the plasma 5-FU concentration-time curve (AUC0-∞) following the intravenous bolus administration of 5-FU and the Cnadir in erythrocyte counts, Hb concentrations, and Hct levels after the 5-FU treatment.

DISCUSSION

The results of the present study suggest that the administration of a pharmacokinetically modified dose of 5-FU could minimize the Cnadir in erythrocyte counts, Hb concentrations, and Hct levels following the administration of 5-FU. The PK-PD model and simulation represent valuable approaches for quantifying and predicting erythropenia as well as determining individual doses and the time at which the subsequent course of the treatment should start.

Semi-physiological pharmacokinetic-pharmacodynamic (PK-PD) modeling and simulation of 5-fluorouracil for thrombocytopenia in rats

1. The aim of this study was to develop a simple pharmacokinetic-pharmacodynamic (PK-PD) model that could characterize the complete time-course of alterations in platelet counts to predict the onset and degree of thrombocytopenia, which severely limits the use of the anticancer agent 5-fluorouracil (5-FU), in rats. 2. Platelet counts were measured in rats following the intravenous administration of various doses of 5-FU for 4 days to obtain data for an analysis of the PK-PD model. Our PK-PD model consisted of a two-compartment PK model, with three compartments for the PD model and 10 structural PK-PD model parameters. 3. After the 5-FU treatment, platelet counts transiently decreased to a nadir level, showed a rebound to above the baseline level before recovering to baseline levels. Nadir platelet counts and rebounds varied with the AUC0-∞ level. The final PK-PD model effectively characterized platelet count data and final PD parameters were estimated with high certainty. 4. This PK-PD model and simulation may represent a valuable tool for quantifying and predicting the complete time-course of alterations in blood cell counts, and could contribute to the development of therapeutic strategies with 5-FU and assessments of various novel anticancer agents that are difficult to examine in humans.

Serum lactate dehydrogenase levels as a predictive marker of oxaliplatin-induced hypersensitivity reactions in Japanese patients with advanced colorectal cancer

OBJECTIVE

Clinical laboratory test data obtained prior to treatments were previously analyzed from the standpoint of susceptibility to hypersensitivity reactions in patients treated with the platimun anticancer agent, oxaliplatin (L-OHP). In the present study, the time course from the first to last cycle of the treatment was additionally analyzed to determine a better predictor of these reactions.

METHODS

A total of 20 laboratory test data were obtained from 108 Japanese patients with advanced colorectal cancer who were treated with the L-OHP-containing regimens, FOLFOX4 and/or mFOLFOX6. The averages and variation coefficients (CV%) of the data until the last cycle of the treatment were compared between patients with hypersensitivity reactions and those without.

RESULTS

The average serum lactate dehydrogenase (LDH) level was lower in patients with grade 1/2 reactions (P=0.016), whereas its CV% value was higher in patients with grade 3/4 reactions (P=0.005) than in those without reactions. An increase in serum LDH levels was observed in some patients with grade 3/4 reactions as the cycle number increased, and thereafter hypersensitivity reactions occurred. This phenomenon was not always observed, but was never detected in patients with grade 1/2 reactions.

CONCLUSIONS

Serum LDH levels may be a predictive marker of hypersensitivity reactions in patients treated with L-OHP. Further extensive examinations with a larger number of patients are needed to establish a patient management strategy.

Commonality of drug-associated adverse events detected by 4 commonly used data mining algorithms

OBJECTIVES

Data mining algorithms have been developed for the quantitative detection of drug-associated adverse events (signals) from a large database on spontaneously reported adverse events. In the present study, the commonality of signals detected by 4 commonly used data mining algorithms was examined.

METHODS

A total of 2,231,029 reports were retrieved from the public release of the US Food and Drug Administration Adverse Event Reporting System database between 2004 and 2009. The deletion of duplicated submissions and revision of arbitrary drug names resulted in a reduction in the number of reports to 1,644,220. Associations with adverse events were analyzed for 16 unrelated drugs, using the proportional reporting ratio (PRR), reporting odds ratio (ROR), information component (IC), and empirical Bayes geometric mean (EBGM).

RESULTS

All EBGM-based signals were included in the PRR-based signals as well as IC- or ROR-based ones, and PRR- and IC-based signals were included in ROR-based ones. The PRR scores of PRR-based signals were significantly larger for 15 of 16 drugs when adverse events were also detected as signals by the EBGM method, as were the IC scores of IC-based signals for all drugs; however, no such effect was observed in the ROR scores of ROR-based signals.

CONCLUSIONS

The EBGM method was the most conservative among the 4 methods examined, which suggested its better suitability for pharmacoepidemiological studies. Further examinations should be performed on the reproducibility of clinical observations, especially for EBGM-based signals.

Genetic polymorphisms in SLC23A2 as predictive biomarkers of severe acute toxicities after treatment with a definitive 5-fluorouracil/cisplatin-based chemoradiotherapy in Japanese patients with esophageal squamous cell carcinoma

OBJECTIVE

Definitive chemoradiotherapy (CRT) with 5-fluorouracil (5-FU) and cisplatin (CDDP) is one of the standard therapies for esophageal squamous cell carcinoma (ESCC); however, inter-individual variations in clinical outcomes have yet to be investigated. In the present study, single nucleotide polymorphisms (SNPs) in SLC23A2 gene were retrospectively evaluated in 49 Japanese patients with ESCC who were treated with a definitive 5-FU/CDDP-based CRT, and the predictive values for the clinical response, severe acute toxicities, and long-term survival were assessed.

METHODS

A course consisted of the continuous infusion of 5-FU at 400 mg/m(2)/day for days 1-5 and 8-12, the infusion of CDDP at 40 mg/m(2)/day on days 1 and 8, and radiation at 2 Gy/day on days 1 to 5, 8 to 12, and 15 to 19, with a second course being repeated after a 2-week interval. The SLC23A2 SNPs rs2681116, rs13037458, rs1715364, rs4987219, and rs1110277 were evaluated.

RESULTS

The rs2681116 and rs13037458 had a tendency to predict the clinical response (p=0.144 and 0.085, respectively) and long-term survival (p=0.142 and 0.056, respectively). The rs4987219 and rs1110277 correlated with severe acute leukopenia (p=0.025) and stomatitis (p=0.019), respectively.

CONCLUSIONS

Further investigations with a larger number of patients or an in vitro study are needed to confirm the predictive values of genetic polymorphisms in SLC23A2.

A survey of the FAERS database concerning the adverse event profiles of α1-adrenoreceptor blockers for lower urinary tract symptoms

PURPOSE

Current guidelines recommend α1-adrenoreceptor blockers (A1Bs) for treating lower urinary tract symptoms suggestive of benign prostatic hyperplasia, but their adverse effects can be problematic. In this study, reports submitted to the US Food and Drug Administration Adverse Event Reporting System (FAERS) between 1997 and 2011 were reviewed to assess the safety profiles of A1Bs.

METHODS

After deleting duplicated submissions and revising arbitrary drug names, reports involving A1Bs for male patients were analyzed. Data mining algorisms were used for the quantitative detection of signals, where a signal represents an association between a drug and an adverse event or a drug-associated adverse event, including the proportional reporting ratio, reporting odds ratio, information component given by a Bayesian confidence propagation neural network, and empirical Bayes geometric mean.

RESULTS

The total number of reports used was 1,260,182. Signal scores suggested the associations of alfuzosin, doxazosin, tamsulosin, and terazosin with dizziness/vertigo, orthostatic hypotension, erectile dysfunction, ejaculation dysfunction (EjD), thirst/dry mouth, and constipation; however, reports on naftopidil, silodosin, and urapidil were not enough to compare with the other 4 A1Bs. Signal scores for EjD were higher for tamsulosin, and those for dizziness/vertigo were lower for doxazosin than for the other 3 drugs.

CONCLUSIONS

Tamsulosin-associated EjD, which was found in clinical studies, was reproduced in this analysis with markedly higher signal scores, and these results strongly suggest the necessity of well-organized clinical studies on A1B-associated adverse events.

Data mining of the public version of the FDA Adverse Event Reporting System

The US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS, formerly AERS) is a database that contains information on adverse event and medication error reports submitted to the FDA. Besides those from manufacturers, reports can be submitted from health care professionals and the public. The original system was started in 1969, but since the last major revision in 1997, reporting has markedly increased. Data mining algorithms have been developed for the quantitative detection of signals from such a large database, where a signal means a statistical association between a drug and an adverse event or a drug-associated adverse event, including the proportional reporting ratio (PRR), the reporting odds ratio (ROR), the information component (IC), and the empirical Bayes geometric mean (EBGM). A survey of our previous reports suggested that the ROR provided the highest number of signals, and the EBGM the lowest. Additionally, an analysis of warfarin-, aspirin- and clopidogrel-associated adverse events suggested that all EBGM-based signals were included in the PRR-based signals, and also in the IC- or ROR-based ones, and that the PRR- and IC-based signals were in the ROR-based ones. In this article, the latest information on this area is summarized for future pharmacoepidemiological studies and/or pharmacovigilance analyses.

Paramyotonia congenita: from clinical diagnosis to in silico protein modeling analysis

BACKGROUND

Paramyotonia congenita (PMC) is an autosomal dominant disorder characterized by cold- or exercise-induced myotonia. PMC is caused by a mutation in SCN4A which encodes the α-subunit of the skeletal muscle sodium channel.

METHODS

The patient was an 11-year-old Japanese girl who was diagnosed as having PMC. To confirm the diagnosis, an orbital ice-pack test and blinking tests were performed. Next, to identify the mutation, genetic analysis of SCN4A was performed. Finally, to evaluate the mutation effect on the protein structure, in silico protein modeling analysis was performed.

RESULTS

Cold- and exercise-induced myotonia was reproduced in the patient with non-invasive bedside tests: ice-pack and blinking tests. In the genetic analysis, a missense mutation, c.4343G>A in SCN4A, was identified, which may result in an arginine to histidine substitution at 1448 in the protein sequence (p.Arg1448His). According to the protein modeling analysis, the mutation neutralized the positive electrostatic charge at 1448 in the DIV/S4 segment and disrupted the beginning of the helical structure in the DIV/S3-S4 linker of the SCN4A protein.

CONCLUSIONS

Diagnostic physical interventions in the patient confirmed the phenotype presentation consistent with PMC, and the in silico protein modeling analysis of p.Arg1448His predicted structural changes which can affect function of the protein. All the data confirmed the diagnosis of PMC in the patient and added to existing literature emphasizing the important role of arginine residue at 1448.

Omeprazole- and esomeprazole-associated hypomagnesaemia: data mining of the public version of the FDA Adverse Event Reporting System

OBJECTIVE

Case reports showing that proton-pump inhibitors (PPIs), omeprazole and esomeprazole, can cause hypomagnesaemia have been accumulating since 2006. In this study, the reports submitted to the Adverse Event Reporting System (AERS) of the US Food and Drug Administration (FDA) were evaluated to assess omeprazole and esomeprazole in terms of susceptibility to hypomagnesaemia.

METHODS

After a revision of arbitrary drug names and the deletion of duplicated submissions, the reports involving omeprazole and esomeprazole were analyzed. Standardized official pharmacovigilance tools were used for the quantitative detection of a signal, i.e., an association between a drug and an adverse drug event, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean.

RESULTS

A total of 22,017,956 co-occurrences were found in 1,644,220 reports from 2004 to 2009, where a co-occurrence was a pair of a drug and an adverse drug event. In total, 818 and 743 adverse drug events were listed as omeprazole- and esomeprazole-associated, with hypomagnesaemia ranking 85th and 135th, respectively. Although both PPIs were associated with hypomagnesaemia, the statistical metrics suggested that the association was more noteworthy for omeprazole.

CONCLUSION

The data obtained in this study do not provide sufficient evidence to recommend systematic monitoring of magnesium levels in plasma, but chronic exposure to a PPI can lead to severe hypomagnesaemia.

Adverse event profiles of 5-fluorouracil and capecitabine: data mining of the public version of the FDA Adverse Event Reporting System, AERS, and reproducibility of clinical observations

OBJECTIVE

The safety profiles of oral fluoropyrimidines were compared with 5-fluorouracil (5-FU) using adverse event reports (AERs) submitted to the Adverse Event Reporting System, AERS, of the US Food and Drug Administration (FDA).

METHODS

After a revision of arbitrary drug names and the deletion of duplicated submissions, AERs involving 5-FU and oral fluoropyrimidines were analyzed. Standardized official pharmacovigilance tools were used for the quantitative detection of signals, i.e., drug-associated adverse events, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean.

RESULTS

Based on 22,017,956 co-occurrences, i.e., drug-adverse event pairs, found in 1,644,220 AERs from 2004 to 2009, it was suggested that leukopenia, neutropenia, and thrombocytopenia were more frequently accompanied by the use of 5-FU than capecitabine, whereas diarrhea, nausea, vomiting, and hand-foot syndrome were more frequently associated with capecitabine. The total number of co-occurrences was not large enough to compare tegafur, tegafur-uracil (UFT), tegafur-gimeracil-oteracil potassium (S-1), or doxifluridine to 5-FU.

CONCLUSION

The results obtained herein were consistent with clinical observations, suggesting the usefulness of the FDA's AERS database and data mining methods used, but the number of co-occurrences is an important factor in signal detection.

THRB genetic polymorphisms can predict severe myelotoxicity after definitive chemoradiotherapy in patients with esophageal squamous cell carcinoma

OBJECTIVE

Chemotherapy-related toxicities are difficult to predict before treatment. In this study, we investigated whether thyroid hormone receptor beta (THRB) genetic polymorphisms can serve as a potential biomarker in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Forty-nine Japanese patients with ESCC who received a definitive chemoradiotherapy (CRT) with 5-fluorouracil and cisplatin in conjunction with concurrent irradiation were retrospectively analyzed. Severe acute toxicities, including leukopenia, stomatitis, and cheilitis, were evaluated according to 6 single nucleotide polymorphisms (SNPs) in the gene; the intronic SNPs of rs7635707 G/T, rs6787255 A/C, rs9812034 G/T, and rs9310738 C/T and the SNPs in the 3'-untranslated region (3'-UTR) of rs844107 C/T and rs1349265 G/A.

RESULTS

Distribution of the 4 intronic SNPs, but not the 2 SNPs in the 3'-UTR, showed a significant difference between patients with and without severe acute leukopenia. Stomatitis and cheilitis were not associated with any of the 6 analyzed SNPs. Frequency of haplotype of the 4 intronic SNPs reached approximately 97% with the 2 major haplotypes G-A-G-C (73.4%) and T-C-T-T (23.5%).

CONCLUSIONS

THRB intronic SNPs can provide useful information on CRT-related severe myelotoxicity in patients with ESCC. Future studies will be needed to confirm these findings.

Aspirin- and clopidogrel-associated bleeding complications: data mining of the public version of the FDA adverse event reporting system, AERS

OBJECTIVE

Adverse event reports (AERs) submitted to the US Food and Drug Administration (FDA) were reviewed to assess the bleeding complications induced by the administration of antiplatelets and to attempt to determine the rank-order of the association.

METHODS

After a deletion of duplicated submissions and the revision of arbitrary drug names, AERs involving warfarin, aspirin, cilostazol, clopidogrel, ethyl icosapentate, limaprost alfadex, sarpogrelate, and ticlopidine were analyzed. Authorized pharmacovigilance tools were used for the quantitative detection of signals, i.e., drug-associated adverse events, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean.

RESULTS

Based on 22,017,956 co-occurrences, i.e., drug-adverse event pairs, found in 1,644,220 AERs from 2004 to 2009, 736 adverse events were listed as warfarin-associated adverse events, and 147 of the 736 were bleeding complications, including haemorrhage and haematoma. Both aspirin and clopidogrel were associated with haemorrhage, but the association was more noteworthy for clopidogrel. As for bleeding complications related to the gastrointestinal system, e.g., melaena and haematochezia, the statistical metrics suggested a stronger association for aspirin than clopidogrel. The total number of co-occurrences was not large enough to compare the association with bleeding complications for the other 5 antiplatelets.

CONCLUSIONS

The data strongly suggest the necessity of well-organized clinical studies with respect to antiplatelet-associated bleeding complications.

VEGF -634C/G genotype is predictive of long-term survival after treatment with a definitive 5-fluorouracil/cisplatin-based chemoradiotherapy in Japanese patients with esophageal squamous cell carcinoma

BACKGROUND

Reports have been accumulating that genetic properties are predictive of clinical response after and/or toxicity during cancer chemotherapy, but little information is available concerning effects on long-term survival. In this study, 49 Japanese patients with esophageal squamous cell carcinoma (ESCC) were followed up for 5 years after treatment with a definitive 5-fluorouracil (5-FU)/cisplatin (CDDP)-based chemoradiotherapy (CRT), and the effects of genotypes of vascular endothelial growth factor (VEGF) were retrospectively revaluated in terms of prediction of long-term survival.

METHODS

A course consisted of the continuous infusion of 5-FU at 400 mg/m(2)/day for days 1-5 and 8-12, the infusion of CDDP at 40 mg/m(2)/day on days 1 and 8, and radiation at 2 Gy/day on days 1 to 5, 8 to 12, and 15 to 19, with a second course repeated after a 2-week interval. The VEGF genotypes -1498T/C, -1154G/A, -634C/G, -7C/T, 936C/T, and 1612G/A were evaluated.

RESULTS

The complete response (CR) rate was 46.9% (23/49). The 5-year survival rate was 42.9 % (21/49). There were 7 patients with a CR, but survival of less than 5 years. They died from myocardial infarction (N=1), sudden cardiac death after suffering from heart failure (N=1), acute myeloid leukemia that developed from myelodysplastic syndromes (N=1), factors not specified (N=2), oropharynx cancer (N=1), and tongue cancer (N=1). VEGF -634C/G had no effect on clinical response, but long-term survival depended on the genotype (p=0.033, Fisher's; p=0.038, Cochran-Armitage; p=0.079, Log-rank). The genotype frequency of 7 patients with a CR, but survival of less than 5 years was different from that for the other 42 patients (p=0.032, Fisher's). None of the other 5 genotypes evaluated affected either clinical response or survival.

CONCLUSIONS

VEGF -634C/G is possibly predictive of long-term survival after treatment with a definitive 5-FU/CDDP-based CRT. Further clinical studies with a larger number of cases are needed to clarify the effects of this genotype.

Statin-associated muscular and renal adverse events: data mining of the public version of the FDA adverse event reporting system

Objective

Adverse event reports (AERs) submitted to the US Food and Drug Administration (FDA) were reviewed to assess the muscular and renal adverse events induced by the administration of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) and to attempt to determine the rank-order of the association.

Methods

After a revision of arbitrary drug names and the deletion of duplicated submissions, AERs involving pravastatin, simvastatin, atorvastatin, or rosuvastatin were analyzed. Authorized pharmacovigilance tools were used for quantitative detection of signals, i.e., drug-associated adverse events, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean. Myalgia, rhabdomyolysis and an increase in creatine phosphokinase level were focused on as the muscular adverse events, and acute renal failure, non-acute renal failure, and an increase in blood creatinine level as the renal adverse events.

Results

Based on 1,644,220 AERs from 2004 to 2009, signals were detected for 4 statins with respect to myalgia, rhabdomyolysis, and an increase in creatine phosphokinase level, but these signals were stronger for rosuvastatin than pravastatin and atorvastatin. Signals were also detected for acute renal failure, though in the case of atorvastatin, the association was marginal, and furthermore, a signal was not detected for non-acute renal failure or for an increase in blood creatinine level.

Conclusions

Data mining of the FDA's adverse event reporting system, AERS, is useful for examining statin-associated muscular and renal adverse events. The data strongly suggest the necessity of well-organized clinical studies with respect to statin-associated adverse events.

Hypersensitivity reactions to anticancer agents: data mining of the public version of the FDA adverse event reporting system, AERS

Background

Previously, adverse event reports (AERs) submitted to the US Food and Drug Administration (FDA) database were reviewed to confirm platinum agent-associated hypersensitivity reactions. The present study was performed to confirm whether the database could suggest the hypersensitivity reactions caused by anticancer agents, paclitaxel, docetaxel, procarbazine, asparaginase, teniposide, and etoposide.

Methods

After a revision of arbitrary drug names and the deletion of duplicated submissions, AERs involving candidate agents were analyzed. The National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 was applied to evaluate the susceptibility to hypersensitivity reactions, and standardized official pharmacovigilance tools were used for quantitative detection of signals, i.e., drug-associated adverse events, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean.

Results

Based on 1,644,220 AERs from 2004 to 2009, the signals were detected for paclitaxel-associated mild, severe, and lethal hypersensitivity reactions, and docetaxel-associated lethal reactions. However, the total number of adverse events occurring with procarbazine, asparaginase, teniposide, or etoposide was not large enough to detect signals.

Conclusions

The FDA's adverse event reporting system, AERS, and the data mining methods used herein are useful for confirming drug-associated adverse events, but the number of co-occurrences is an important factor in signal detection.