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Objective: The aim of the study was to perform a meta-analysis of randomized clinical trials to compare the clinical efficacy and safety between combination of cyclin-dependent kinase (CDK) 4/6 inhibitors with aromatase inhibitors (AIs) and AIs alone in patients with hormone receptor+/human epidermal growth factor receptor type2-(HR+/HER2-) advanced breast cancer. Methods: Published clinical studies were identified through electronic database searches until February 2019. Literature qualities were assessed by the Scottish Intercollegiate Guidelines Network Checklist. Key endpoints of efficacy were progression-free survival (PFS), objective response rate (ORR), and clinical benefit (CB). Endpoints of safety were adverse events (AEs) (neutropenia, leukopenia, any grade 3/ 4 AEs, and serious AEs) and on-treatment death. Meta-analysis was performed using the RevMan 5.3 software. Results: The selected five studies were evaluated as “good” in quality assessment. Compared to AIs alone, the combination therapy significantly improved PFS (pooled hazard ratio=0.55; 95% confidence interval (CI) 0.49-0.62), ORR (odds ratio=1.78; 95% CI=1.49-2.13), and CB (odds ratio=1.86; 95% CI=1.51-2.28). The prevalence of AEs was significantly higher in the combination group than in the AIs alone group. On-treatment death was greater in the combination group than in the AIs alone group, although insignificant. Conclusion: The combination therapy of CDK4/6 inhibitors with AIs was more effective for the treatment of HR+/HER2- advanced breast cancer, but less safe than AIs alone. The combination therapy should be effectively managed through patient monitoring, and further studies are needed to reduce AEs in the combination therapy of CDK4/6 inhibitors with AIs.

Background: Nivolumab and pembrolizumab are antagonists of the programmed death-ligand 1 (PD-L1) receptor that function as immuno-oncological agents. This study aimed to evaluate the safety and efficacy of nivolumab and pembrolizumab in elderly patients in outpatient settings. Methods: The safety and efficacy of nivolumab and pembrolizumab were compared retrospectively among patients at the Veterans Health Service (VHS) Medical Center in Seoul, South Korea, from September 1, 2017 to August 25, 2018. Results: Eighty-seven patients were selected for the study. The median progression-free survival was 63 days for nivolumab (95% confidence interval (CI), [14 to 282]) vs. 243 days for pembrolizumab (95% CI, [22 to 348]) (p =0.04). The objective response rate (ORR) was 0% in the nivolumab group vs 5.6% in the pembrolizumab group (p =0.310). All the patients exhibited treatmentrelated adverse effects. More than 89% of the patients exhibited diseases of the gastrointestinal (GI) tract. Pneumonia, of grades three or higher, was the most common adverse effect, followed by weakness and anorexia. Conclusions: There was no statistically significant difference between the nivolumab group and the pembrolizumab group with respect to the ORR. The incidence and severity of the adverse effects in this study were higher than those of previous studies; however, these adverse effects are generally manageable in a real-world clinical setting. Further randomized controlled studies will be necessary to confirm these results in elderly patients.

Objective: To describe patterns of spontaneous reporting on adverse events following immunization (AEFIs) using the human papilloma virus (HPV) vaccine according to the Brighton Collaboration (BC) criteria. Methods: We used the Korea Adverse Event Reporting System (KAERS) database including vaccinations between 2008 and 2017. To apply BC criteria, we classified 58 BC AEFIs into World Health Organization Adverse Reaction Terminology (WHO-ART) codes. We applied MedDRA standard medical queries that were pre-defined as five BC AEFIs. Terminology mapping between MedDRA and WHO-ART terms was performed by three researchers. Descriptive statistics of individual case safety reports were analyzed according to BC applicability. Disproportionality analyses were performed on each BC AEFI and each preferred AEFI term according to the case-noncase approach; reporting odds ratio (ROR) and 95% confidence intervals (CI) were calculated. Results: Among the 30,266 reports of vaccinations between 2008 and 2017, 2,845 reports included the HPV vaccine. Of these reports, 1,511 (53.1%) included at least one BC AEFI. Reports from physicians or manufacturers included more BC AEFIs than from other reporters. Injection site reactions and fever were frequently reported in BC AEFIs; spontaneous abortion and ectopic pregnancy (ROR, 14.29 [95% CI, 4.30-47.49]) and vasculitic peripheral neuropathy (ROR, 8.57 [95% CI, 2.61-28.10]) showed the highest ROR. Among non-BC AEFIs, dizziness or myalgia were frequently reported; exposure during pregnancy (ROR, 23.95 [95% CI, 16.27-35.25]) and inappropriate schedule of administration (ROR, 22.89 [95% CI, 16.74-31.31]) showed the highest ROR. Conclusion: BC criteria would be applicable for labeled AEFIs, whereas analyzing non-BC AEFIs would be useful for detecting unlabeled AEFIs.

Objective: The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are frequently prescribed medications worldwide for the treatment of hypercholesterolemia. Statins are considered to be well tolerated; however, they have a potential for myotoxicity. Concomitant drugs that inhibit cytochrome P450 3A4 can increase the concentration of statins and thus the risk of developing myotoxicity. The purpose of this study was to evaluate risk factors associated with potential drug-drug interactions in patients receiving statins. Methods: The subjects of this study were patients aged more than 18 years who received at least one prescription of statins in a general hospital located in Chuncheon-si, Korea, between January 1, 2018, and March 31, 2018. Data regarding statin use and baseline characteristics was collected from the computerized hospital database. Logistic regression analysis was used to identify risk factors associated with potential drug-drug interactions. Results: A total of 1061 patients were finally included in the study. The incidence of potential drug-drug interactions was 45% in all subjects. According to the results of the multivariate logistic regression analysis, myocardial infarction as the indication of statin, arrhythmia or heart failure as a comorbidity, and aspartate aminotransferase levels higher than 40 IU/L were significant risk factors for potential drug-drug interactions in study subjects. Diltiazem was the most commonly co-prescribed drug that caused potential drug-drug interactions with statins. Conclusion: There was a considerable rate of potential drug-drug interactions in patients receiving statins. Health care professionals should attempt to reduce potential drug-drug interactions during statin administration.

Background: Tacrolimus, a calcineurin inhibitor, is an immunosuppressant used in post-transplantation maintenance therapy. The drug has a narrow therapeutic range and requires periodic therapeutic drug monitoring. Although many studies have reported the effects of intrapatient variability of tacrolimus on survival, rejection, and complications in renal transplant recipients, very few studies have reported these effects in liver transplant recipients. The purpose of this study was to evaluate the effect of intrapatient variability of tacrolimus on clinical outcomes after liver transplantation. Methods: Intrapatient variability was calculated using individual, averaged tacrolimus concentrations. Patients were divided into two groups according to their median variability value: high-variability and low-variability groups. The rate of deviation from the therapeutic range, incidence of acute rejection, posttransplant diabetes, incidence of infection, and estimated glomerular filtration rate (eGFR) after transplantation were compared between the groups. Results: Of the total patients (n=82), the high-variability group (n=41) exhibited significantly greater deviation from the therapeutic range (65.92% vs. 56.84%; p<0.001). There was no significant difference in acute rejection or posttransplantation diabetes incidence or eGFR; however, the number of infection in the first 6 months was significantly lower in the low-variability group (0.4 vs. 0.9 times; p=0.039). Multiple linear regression analysis showed that the number of infection significantly increased as intrapatient variability increased (p=0.015). Conclusion: High intrapatient variability in tacrolimus concentrations was strongly associated with an increased frequency of deviation from the suggested therapeutic range and an increased number of infection.

Background: Drug-drug interactions (DDIs) in patients using oral anticancer treatment are more common than in those using injectable anticancer agents. In addition, DDIs related to anticancer treatment are known to cause clinically significant outcomes, such as treatment failure and severe toxicity. To prevent these negative outcomes, significant DDIs are monitored and managed using the information provided in drug databases. We aimed to evaluate the consistency of information on clinically significant DDIs for tyrosine kinase inhibitors (TKIs) between representative drug databases. Methods: We selected clinically significant DDIs involving medications that are co-prescribed with TKIs and met the following criteria: the severity level of DDIs was equal or greater than “D” in Lexicomp® or “major” in Micromedex®. We then analyzed the consistency of the severity classification and evidence level between the drug databases. Spearman’s correlation coefficient was used to identify the relationship between DDI information in the drug databases. Results: In total, 627 DDI pairs were identified as clinically significant; information on these was provided by Lexicomp® and Micromedex® for 571 and 438 pairs, respectively, and both drug databases provided information on 382 DDI pairs. There was no correlation between the severity and evidence level of DDIs provided in the two databases; Spearman’s correlation coefficient for Lexicomp® and Micromedex® was -0.009 (p=0.861) and -0.064 (p=0.209), respectively. Conclusion: To judge the significance of DDIs, healthcare providers should consider that the information on DDIs may be different between drug information databases; hence, clinical factors must be considered concurrently.

Background: Prevention of osteoporosis and bone fracture is one of the important issues for liver transplant recipients because a long history of liver disease and lifelong use of immunosuppressants, including corticosteroids, may cause these diseases. In this study, we aimed to analyze liver recipient bone status, 10-year fracture risk, and medication history. Methods: The electronic medical records of adult patients aged >40 years who received liver transplantation at Seoul National University Bundang Hospital between January 2009 and June 2017 were reviewed retrospectively. On the basis of their bone mineral density and fracture history, their fracture risks were analyzed using the Korean fracture risk assessment tool. Results: A total of 57 liver transplant recipients were treated with corticosteroids during a mean of 8.8 months after transplantation. 30 patients (52.6%) showed bone metabolism dysfunction such as osteopenia or osteoporosis. The 10-year femoral fracture risk was 2.1%, and dual-energy X-ray absorptiometry monitoring was performed, including right before liver transplantation every 27.5±19.2 months. The mean femoral bone mineral density decreased by −7.2%±7.3%. Four patients (7.0%) had a fracture after liver transplantation. Osteoporotic fracture occurred in 3 patients with osteoporosis (25.0%). Among the osteopenia patients with moderate fracture risk who were not treated with bisphosphonate, 1 patient (12.5%) had a history of bone fracture after liver transplantation. Conclusions: Considering the deterioration of bone density and moderate fracture risk, medication for osteoporosis should be prescribed to liver transplant recipients with regular monitoring of bone density after transplantation.

The emergence of phosphodiesterase (PDE) 5 inhibitors gave rise to the solution for erectile dysfunction, starting with the development of sildenafil. Although their efficacy in treating erectile dysfunction has been shown, the side effects of PDE5 inhibitors, especially sildenafil, must be taken into consideration. A 64-year-old man received 100 mg of sildenafil and experienced blue vision in both eyes; however, after a day or so, his symptoms improved. The symptoms disappeared when he stopped administering sildenafil, but reappeared when the medication was re-administered. Therefore, he discontinued sildenafil treatment and was prescribed udenafil instead. After that, visual adverse events no longer occurred. Causality assessment showed that in this case, sildenafil-induced cyanopsia was “certain” under the World Health Organization-Uppsala Monitoring Center (WHO-UMC) criteria and Korean causality assessment algorithm (Ver.2), and was “probable” according to the Naranjo scale. In addition, sildenafil also led to abnormal visual reactions in other cases. Sildenafil can also inhibit PDE6, which is present in retinal cells, unlike other PDE5 inhibitors. Thus, visual adverse reactions, such as blue vision, are the unique results of sildenafil, and other PDE5 inhibitors may be used to prevent them.