Real-World Utilization Patterns of Long-Acting Injectable Antipsychotics in Canada: A Retrospective Study.

Objective: The objective of this study was to analyze the real-world prevalence of long-acting injectable (LAI) antipsychotic use and determine when LAIs are being used in sequencing of antipsychotic medications among Canadian patients with schizophrenia. Methods: This was a retrospective, longitudinal cohort study using Canadian pharmacy prescription data between August 2005 and June 2017. Patients with inferred schizophrenia spectrum disorder were indexed on the date of their first antipsychotic prescription and analyzed for minimum 12 months to track lines of antipsychotic therapy and LAI utilization. Results: A total of 16,300 patients were identified for analysis. 48.2% and 46.0% of index antipsychotic prescriptions were prescribed by a general practitioner/family medicine doctor and psychiatrist, respectively. 1,062 (6.5%) patients used an LAI during the study period. Of those patients, 789 used an LAI within two years of index (74.3% of LAI users; 4.8% of all patients). The majority of LAI use (62.0%) occurred in the third line of therapy or later. 65.0% of patients had tried at least two therapy lines, and most patients reported gaps of six months to one year between treatment lines. Conclusion: Despite their potential to reduce relapse in schizophrenia by improving treatment adherence, this study shows LAIs continue to be under-utilized in Canada. When used, LAIs are positioned late in sequencing of antipsychotic medications, often not initiated until years after diagnosis. Continued preference for oral APs with poor adherence may be negatively impacting prognosis and exacerbating burden of schizophrenia. Efforts should be invested to understand barriers to LAI uptake and advocate for earlier, widespread use of LAIs.

Noninvasive Prenatal Detection of Trisomy 21 by Targeted Semiconductor Sequencing: A Technical Feasibility Study.

OBJECTIVE: To develop an alternate noninvasive prenatal testing method for the assessment of trisomy 21 (T21) using a targeted semiconductor sequencing approach. METHODS: A customized AmpliSeq panel was designed with 1,067 primer pairs targeting specific regions on chromosomes 21, 18, 13, and others. A total of 235 samples, including 30 affected with T21, were sequenced with an Ion Torrent Proton sequencer, and a method was developed for assessing the probability of fetal aneuploidy via derivation of a risk score. RESULTS: Application of the derived risk score yields a bimodal distribution, with the affected samples clustering near 1.0 and the unaffected near 0. For a risk score cutoff of 0.345, above which all would be considered at "high risk," all 30 T21-positive pregnancies were correctly predicted to be affected, and 199 of the 205 non-T21 samples were correctly predicted. The average hands-on time spent on library preparation and sequencing was 19 h in total, and the average number of reads of sequence obtained was 3.75 million per sample. CONCLUSION: With the described targeted sequencing approach on the semiconductor platform using a custom-designed library and a probabilistic statistical approach, we have demonstrated the feasibility of an alternate method of assessment for fetal T21.

Mechanisms of reduced maternal and fetal lopinavir exposure in a rat model of gestational diabetes.

Lopinavir (LPV) is the preferred HIV protease inhibitor in pregnancy, but it is unknown if gestational diabetes mellitus (GDM) affects its disposition. Hepatic protein expression and plasma protein binding are altered in rodent models of GDM. Because LPV is influenced by hepatic transporters and metabolic enzymes and is highly protein bound, it was hypothesized that streptozotocin-induced GDM would alter its disposition. Maternal and fetal tissues were collected from GDM rats and controls 45 min after LPV injection. In another cohort, fetuses were serially extracted 5 to 60 min after injection. LPV was quantified using liquid chromatography tandem mass spectrometry. Expression of relevant transporters, such as Multidrug resistance protein 1 (Mdr1), and cytochrome P450 3a2 (Cyp3a2), which metabolizes LPV in rodents, was measured in maternal liver via quantitative reverse transcriptase polymerase chain reaction and Western blot analysis. Expression of relevant transporters also was measured in placenta via quantitative reverse transcriptase polymerase chain reaction. Protein binding was determined by ultrafiltration. Relative to controls, we observed dramatically reduced maternal and fetal LPV exposure in GDM. Compared with controls, maternal hepatic Mdr1 and Cyp3a2 were up-regulated, and protein binding was reduced in the GDM group. Increased Mdr1- and Cyp3a2-mediated hepatobiliary clearance, coupled with a larger unbound LPV fraction, is likely to have facilitated hepatic elimination, thereby decreasing maternal and fetal exposure. Not surprisingly, up-regulation of Mdr1 and Cyp3a2's transcriptional regulator, pregnane X receptor, was demonstrated in maternal liver via Western blot analysis. Up-regulation of Mdr1 in placentas isolated from the GDM group likely also contributed to decreased fetal exposure to LPV. This study provides preclinical support for an as yet unreported drug-disease (LPV-GDM) interaction.

Impact of hyperlipidemia on plasma protein binding and hepatic drug transporter and metabolic enzyme regulation in a rat model of gestational diabetes.

It is currently unknown whether gestational diabetes mellitus (GDM), a prevalent obstetrical complication, compounds the changes in drug disposition that occur naturally in pregnancy. Hyperlipidemia occurs in GDM. Using a rat model of GDM, we determined whether excess lipids compete with drugs for plasma protein binding. Because lipids activate nuclear receptors that regulate drug transporters and metabolic enzymes, we used proteome analysis to determine whether hyperlipidemia indirectly leads to the dysregulation of these proteins in the liver. GDM was induced on gestational day 6 (GD6) via streptozotocin injection. Controls received either vehicle alone or streptozotocin with subsequent insulin treatment. Liver and plasma were collected on GD20. Glyburide and saquinavir protein binding was determined by ultrafiltration, and an established solvent method was used for plasma delipidation. Proteomics analysis was performed by using isobaric tags for relative and absolute quantitation methodology with membrane-enriched hepatic protein samples. Relative to controls, GDM rat plasma contained more cholesterol and triglycerides. Plasma protein binding of glyburide and saquinavir was decreased in GDM. Delipidation normalized protein binding in GDM plasma. Proteins linked to lipid metabolism were strongly affected in the GDM proteomics data set, with prohyperlipidemic and antihyperlipidemic changes observed, and formed networks that implicated several nuclear receptors. Up-regulation of drug transporters and metabolic enzymes was observed (e.g., multidrug resistance 1/2, CYP2A1, CYP2B9, and CYP2D3). In this study, GDM-induced hyperlipidemia decreased protein binding and was associated with drug transporter and metabolic enzyme up-regulation in the liver. Both of these findings could change drug disposition in affected pregnancies, compounding changes associated with pregnancy itself.

Breast cancer resistance protein (BCRP)-mediated glyburide transport: effect of the C421A/Q141K BCRP single-nucleotide polymorphism.

The antidiabetic agent glyburide (glibenclamide) is frequently used for the treatment of type II diabetes and is increasingly being used for the treatment of gestational diabetes. Evidence suggests that breast cancer resistance protein/ATP-binding cassette, subfamily G, member 2 (ABCG2) expressed in the placenta protects the fetus against the accumulation of glyburide. A number of studies have investigated the significance of several single-nucleotide polymorphisms (SNPs) in the ABCG2 gene. Associations between the Q141K (C421A) SNP and ABCG2 protein expression, membrane surface translocation, efflux activity, or ATPase activity have been shown. Therefore, alterations in glyburide transport across the placenta, resulting in increased fetal glyburide exposure, may be seen in individuals carrying the C421A allele. The purpose of this study is to investigate whether the Q141K SNP causes alterations in ABCG2-mediated glyburide transport. Glyburide accumulation assays were carried out with stably transfected human embryonic kidney (HEK)-293 cells expressing wild-type ABCG2 (Arg482) and polymorphic ABCG2 (Q141K). Glyburide kinetic parameters were determined for comparison of wild-type and SNP ABCG2 activity by simultaneously fitting data for ABCG2-expressing cells (saturable transport) and empty vector-expressing cells (nonsaturable transport) by nonlinear regression analysis. The apparent K(t) and V(max) values for the transfected HEK-293 cells expressing the polymorphic variant (Q141K) of ABCG2 were significantly higher than those values determined for the wild-type ABCG2-expressing cells (p < 0.05). Our results indicate that the Q141K variant of ABCG2 may have the potential to alter the placental pharmacokinetics of glyburide used in pregnancy.

Impact of acute streptozotocin-induced diabetes on ABC transporter expression in rats.

Hepatic ABC efflux transporters control the cellular uptake (in basolateral membranes) and excretion (in apical membranes) of many substrates. Since type-1 diabetes mellitus (T1DM) is associated with altered hepatobiliary excretion of many endogenous and exogenous substances, we examined key hepatic ABC transporters and levels of the endogenous substrate glutathione in rats with acute streptozotocin-induced T1DM. Renal transporters and inflammatory markers were also examined. Abcb1, Abcc1-4, and Abcg2 were measured using qRT-PCR. Glutathione was measured in liver tissue, plasma, and urine. Inflammatory markers, including C-reactive protein (CRP), were measured in plasma via ELISA. In diabetic rats, Abcb1a, Abcc2, and Abcg2 (apical) were decreased, while Abcc4 (basolateral) was increased. Abcb1a and Abcc2 inversely correlated with plasma CRP. Diabetic and control rats exhibited similar hepatic glutathione, but levels in diabetic plasma were lower. When standardized to urinary output, diabetic rats excreted 6.7-fold more glutathione in urine than controls. Renal transporter levels were normal in diabetic rats. Results show apical transporters involved in hepatobiliary excretion are downregulated in T1DM, possibly through an inflammation-mediated process. Findings suggest that there may be a vectorial shift from hepatic to renal excretion for some substrates in T1DM.

X-linked deafness-2 (DFNX2) phenotype associated with a paracentric inversion upstream of POU3F4.

PURPOSE: The authors report on a 7-year-old male, designated FR, who has severe sensorineural hearing loss. Features include a round face, hypertelorism, epicanthal folds, and flat nasal root. Although there were early developmental concerns regarding FR, all but his speech delay resolved when he was placed in an educational program that accommodated his hearing loss. Genetic studies were performed to investigate genetic causes for his hearing loss. METHOD: History, physical examination, audiologic assessment, and imaging were performed according to usual practice. FMR1,GJB2,GJB6, and POU3F4 genes were sequenced. Chromosomal studies consisted of karyotyping and breakpoint analysis by fluorescence in situ hybridization (FISH). RESULTS: Results from FMR1,GJB2,GJB6, and POU3F4 sequencing and echocardiography, electrocardiogram, and abdominal ultrasound were normal. A computed tomography (CT) scan revealed a large fundus of the internal auditory canals and absence of the bony partition between the fundus and the adjacent cochlear turns, with a widened modiolus bilaterally. FR's CT findings were consistent with those described in persons with X-linked deafness-2 (DFNX2) hereditary deafness. FR's karyotype was 46,inv(X)(q13q24),Y.ish inv(X)(XIST+)mat. FISH refined the breakpoints to inv(X)(q21.1q22.3). The Xq21.1 breakpoint was narrowed to a 25-kb region 450 kb centromeric to the DFNX2 gene, POU3F4. There are rare case reports of DFNX2 patients with chromosomal rearrangements positioned centromeric to POU3F4 and no mutations within the gene. CONCLUSION: Authors hypothesized that FR's hearing loss was caused by dysregulation of POU3F4 due to separation from regulatory elements affected by the inversion.

Expression of ABC Efflux transporters in placenta from women with insulin-managed diabetes.

Drug efflux transporters in the placenta can significantly influence the materno-fetal transfer of a diverse array of drugs and other xenobiotics. To determine if clinically important drug efflux transporter expression is altered in pregnancies complicated by gestational diabetes mellitus (GDM-I) or type 1 diabetes mellitus (T1DM-I), we compared the expression of multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 2 (MRP2) and the breast cancer resistance protein (BCRP) via western blotting and quantitative real-time polymerase chain reaction in samples obtained from insulin-managed diabetic pregnancies to healthy term-matched controls. At the level of mRNA, we found significantly increased expression of MDR1 in the GDM-I group compared to both the T1DM-I (p<0.01) and control groups (p<0.05). Significant changes in the placental protein expression of MDR1, MRP2, and BCRP were not detected (p>0.05). Interestingly, there was a significant, positive correlation observed between plasma hemoglobin A1c levels (a retrospective marker of glycemic control) and both BCRP protein expression (r = 0.45, p<0.05) and BCRP mRNA expression (r = 0.58, p<0.01) in the insulin-managed DM groups. Collectively, the data suggest that the expression of placental efflux transporters is not altered in pregnancies complicated by diabetes when hyperglycemia is managed; however, given the relationship between BCRP expression and plasma hemoglobin A1c levels it is plausible that their expression could change in poorly managed diabetes.

Management of HIV positive pregnancies in Ontario: current status.

BACKGROUND: AIDS is one of the biggest health crises we face today. With nearly 20 million women infected with the virus that causes it, HIV, maternal transmission of HIV is increasingly becoming a serious concern and hindrance in stemming the proliferation of the disease. While an ever increasing number of pregnant women are being administered anti-retrovirals to mitigate the vertical transmission of the virus, little is known about the changing trends in the type of agents used and the duration of therapy. OBJECTIVES: This paper attempts to identify any changes in the pattern of HIV management in pregnant women for the period of time spanning 1998 to 2005. METHODS: Data from the charts of 183 patients were reviewed. A retrospective, longitudinal and cross-sectional patient chart review was employed to obtain data. Parameters such as therapeutic management of HIV, class of drugs used and duration of treatment were assessed to identify any evolving patterns over the course of the study. RESULTS: It was seen that over time, the number of women receiving adequate therapeutic interventions has steadily increased. We also identified evolving trends in terms of the classes of anti-retrovirals employed and the duration of prophylaxis. CONCLUSION: The strategies employed in the management of HIV positive pregnancies in Ontario, while evolving over time, were found to be in line with the guidelines in place. The information delivered by this study might enable the medical community to assess the progress in dealing with this challenge thus far and further fine tune the current strategy.