Safety Surveillance During Drug Development: Comparative Evaluation of Existing Regulations.

Drug safety monitoring is essential for developing efficient and safe treatments. It starts with preclinical toxicology studies and continues with the observation and analysis of potentially harmful effects in humans throughout the whole drug life cycle. Safety surveillance during the clinical phase is of paramount importance for protecting the health of clinical trial (CT) participants at a period when relatively little is known about the drug safety profile, and for reassuring that detected risks are minimized when the product obtains marketing approval. This review aimed to investigate current safety surveillance methods during drug development worldwide, in order to identify potential gaps and opportunities for amelioration. To this end, international guidelines, standards, and local legislations about CTs were reviewed and compared. Our review revealed common strategies, mainly in alignment with international guidelines, especially concerning the systematic collection, assessment, and expedition of adverse events by investigators and sponsors and the preparation of periodic aggregate safety reports by sponsors, as a means to inform health authorities (HAs) about the evolving benefit-risk balance of the investigational product. Inconsistencies in safety surveillance mainly concerned local expedited reporting requirements. Significant gaps were identified in the methodologies for aggregate analyses and the responsibilities of HAs. Addressing the regulatory discrepancies and harmonizing the safety surveillance processes at a global level would increase the usability of safety data accumulated by clinical studies worldwide, thus enabling and hopefully accelerating the development of safe and efficient drug therapies.

Discrepancies Between the Labels of Originator and Generic Pharmaceutical Products: Implications for Patient Safety.

BACKGROUND: All drug marketing authorization holders have the legal obligation to collect data on the use of the products they market and to keep the labels of those products updated. As demonstrated by previous studies, many generic products have labels that are discrepant from the labels of their reference (originator) products. This fact may cause inconsistent messages to be disseminated to healthcare professionals and patients for the same active ingredient. OBJECTIVE: These potential label discrepancies led us to investigate the degree of difference between labels for generic and originator products, the possible consequences of this discrepancy for patients, and its implications for risk minimization. PRODUCTS AND METHODS: Drugs from different Anatomical Therapeutic Chemical classes were randomly selected from the Electronic Medicines Compendium. For each drug, the consistency and discrepancies between the summaries of product characteristics (SmPCs) for originator and generic products were analyzed for each safety-relevant section of the SmPC separately as well as across all of its sections. The percentile distribution of discrepancy classifications was calculated. The same method was applied when determining the potential impact of label discrepencies on patients. RESULTS: Among the 50 drugs selected initially, 31 were eligible for the study and were analyzed further. Of those 31 drugs, 13 (41.9%) presented critical label differences between originator and generic products, 6 (19.4%) showed major label differences, 7 (22.6%) exhibited minor label differences, and 5 (16.1%) showed very minor label differences. Over 60% of the selected drugs (19, 61.3%) presented important (critical, major) label differences between originator and generic products. None of the selected drugs had fully aligned labels of originator and generic products. Label misalignments that could potentially have a fatal or life-threatening impact on the patient were observed for 4 (12.9%) of the selected drugs. Label misalignments that could have a severe patient outcome were noted for 11 (35.5%) of the selected drugs, and label misalignments that could have a medium impact on the patient were seen for 6 (19.35%) of the selected drugs. The label misalignments observed for 10 (32.25%) of the selected drugs would potentially lead to only a minor or no effect on the patient. Almost half (15, 48.4%) of the selected drugs presented label misalignments that could have a critical (fatal, life-threatening, severe) influence on the patient. CONCLUSIONS: In this sample, SmPC alignment between generic and originator medicinal products was found to be inefficient for established drugs, and could lead to the diffusion of discrepant messages to healthcare professionals and patients. In order to address this SmPC alignment problem, health authorities such as the EMA and the FDA must conduct retrospective analyses of all drugs on the market as a first step towards realigning labels. These analyses could be performed during the evaluation of aggregate reports.

CD8 Binding of MHC-Peptide Complexes in cis or trans Regulates CD8+ T-cell Responses.

The coreceptor CD8αß can greatly promote activation of T cells by strengthening T-cell receptor (TCR) binding to cognate peptide-MHC complexes (pMHC) on antigen presenting cells and by bringing p56Lck to TCR/CD3. Here, we demonstrate that CD8 can also bind to pMHC on the T cell (in cis) and that this inhibits their activation. Using molecular modeling, fluorescence resonance energy transfer experiments on living cells, biochemical and mutational analysis, we show that CD8 binding to pMHC in cis involves a different docking mode and is regulated by posttranslational modifications including a membrane-distal interchain disulfide bond and negatively charged O-linked glycans near positively charged sequences on the CD8ß stalk. These modifications distort the stalk, thus favoring CD8 binding to pMHC in cis. Differential binding of CD8 to pMHC in cis or trans is a means to regulate CD8+ T-cell responses and provides new translational opportunities.

Risk of QT prolongation and torsade de pointes associated with exposure to hydroxyzine: re-evaluation of an established drug.

Several noncardiac drugs have been linked to cardiac safety concerns, highlighting the importance of post-marketing surveillance and continued evaluation of the benefit-risk of long-established drugs. Here, we examine the risk of QT prolongation and/or torsade de pointes (TdP) associated with the use of hydroxyzine, a first generation sedating antihistamine. We have used a combined methodological approach to re-evaluate the cardiac safety profile of hydroxyzine, including: (1) a full review of the sponsor pharmacovigilance safety database to examine real-world data on the risk of QT prolongation and/or TdP associated with hydroxyzine use and (2) nonclinical electrophysiological studies to examine concentration-dependent effects of hydroxyzine on a range of human cardiac ion channels. Based on a review of pharmacovigilance data between 14th December 1955 and 1st August 2016, we identified 59 reports of QT prolongation and/or TdP potentially linked to hydroxyzine use. Aside from intentional overdose, all cases involved underlying medical conditions or concomitant medications that constituted at least 1 additional risk factor for such events. The combination of cardiovascular disorders plus concomitant treatment of drugs known to induce arrhythmia was identified as the greatest combined risk factor. Parallel patch-clamp studies demonstrated hydroxyzine concentration-dependent inhibition of several human cardiac ion channels, including the ether-a-go-go-related gene (hERG) potassium ion channels. Results from this analysis support the listing of hydroxyzine as a drug with "conditional risk of TdP" and are in line with recommendations to limit hydroxyzine use in patients with known underlying risk factors for QT prolongation and/or TdP.

A-kinase anchoring protein Lbc coordinates a p38 activating signaling complex controlling compensatory cardiac hypertrophy.

In response to stress, the heart undergoes a remodeling process associated with cardiac hypertrophy that eventually leads to heart failure. A-kinase anchoring proteins (AKAPs) have been shown to coordinate numerous prohypertrophic signaling pathways in cultured cardiomyocytes. However, it remains to be established whether AKAP-based signaling complexes control cardiac hypertrophy and remodeling in vivo. In the current study, we show that AKAP-Lbc assembles a signaling complex composed of the kinases PKN, MLTK, MKK3, and p38α that mediates the activation of p38 in cardiomyocytes in response to stress signals. To address the role of this complex in cardiac remodeling, we generated transgenic mice displaying cardiomyocyte-specific overexpression of a molecular inhibitor of the interaction between AKAP-Lbc and the p38-activating module. Our results indicate that disruption of the AKAP-Lbc/p38 signaling complex inhibits compensatory cardiomyocyte hypertrophy in response to aortic banding-induced pressure overload and promotes early cardiac dysfunction associated with increased myocardial apoptosis, stress gene activation, and ventricular dilation. Attenuation of hypertrophy results from a reduced protein synthesis capacity, as indicated by decreased phosphorylation of 4E-binding protein 1 and ribosomal protein S6. These results indicate that AKAP-Lbc enhances p38-mediated hypertrophic signaling in the heart in response to abrupt increases in the afterload.

A-kinase anchoring protein (AKAP)-Lbc anchors a PKN-based signaling complex involved in α1-adrenergic receptor-induced p38 activation.

The mitogen-activated protein kinases (MAPKs) pathways are highly organized signaling systems that transduce extracellular signals into a variety of intracellular responses. In this context, it is currently poorly understood how kinases constituting these signaling cascades are assembled and activated in response to receptor stimulation to generate specific cellular responses. Here, we show that AKAP-Lbc, an A-kinase anchoring protein (AKAP) with an intrinsic Rho-specific guanine nucleotide exchange factor activity, is critically involved in the activation of the p38α MAPK downstream of α(1b)-adrenergic receptors (α(1b)-ARs). Our results indicate that AKAP-Lbc can assemble a novel transduction complex containing the RhoA effector PKNα, MLTK, MKK3, and p38α, which integrates signals from α(1b)-ARs to promote RhoA-dependent activation of p38α. In particular, silencing of AKAP-Lbc expression or disrupting the formation of the AKAP-Lbc·p38α signaling complex specifically reduces α(1)-AR-mediated p38α activation without affecting receptor-mediated activation of other MAPK pathways. These findings provide a novel mechanistic hypothesis explaining how assembly of macromolecular complexes can specify MAPK signaling downstream of α(1)-ARs.

Detection of sites of infection in mice using 99mTc-labeled PN(2)S-PEG conjugated to UBI and 99mTc-UBI: a comparative biodistribution study.

UNLABELLED: The antimicrobial peptide ubiquicidin (UBI) directly labeled with technetium-99m ((99m)Tc) has recently been shown to be specifically taken up at sites of infection; however, its chemical structure is not well defined. To address this problem, the aim of the present study was to label UBI using poly(ethyleneglycol)-N-(N-(3-diphenylphosphinopropionyl)glycyl)-S-tritylcysteine ligand (PEG-PN(2)S) in order to compare its ability to detect infection sites with that of (99m)Tc-UBI. METHODS: The PN(2)S-PEG-UBI conjugate was prepared and labeled with (99m)Tc, and its radiochemical purity was subsequently assessed. The stability of the conjugate to cysteine challenge and dilution with both saline solution and phosphate buffer was determined and serum stability and protein binding were also assessed. In vivo studies were carried out in healthy mice to study the biodistribution of (99m)Tc-PN(2)S-PEG-UBI and its precursor (99m)Tc-PN(2)S-PEG and in infected mice to compare the uptakes of (99m)Tc-UBI and (99m)Tc-PN(2)S-PEG-UBI at the site of infection using scintigraphic imaging and ex vivo tissue counting. RESULTS: (99m)Tc-PN(2)S-PEG-UBI was obtained with high radiochemical purity (98+/-1%) and high stability. The amphiphilic nature of the conjugate leads to a tendency to form micellar aggregates that explain the high protein binding values obtained. Biodistribution studies in mice showed low renal clearance followed by a predominant reticuloendothelial system clearance that limits its application in the abdominal area. Statistical analysis revealed no significant difference between (99m)Tc-UBI and (99m)Tc-PN(2)S-PEG-UBI uptake in infected mouse thigh, and the site of infection was clearly visualized using scintigraphic imaging. CONCLUSIONS: (99m)Tc-PN(2)S-PEG-UBI proved to be as effective as (99m)Tc-UBI in detecting sites of infection; however, the well-defined chemical structure of (99m)Tc-PN(2)S-PEG-UBI makes it a better candidate for clinical imaging of infection.