PK/PD and Bioanalytical Considerations of AAV-Based Gene Therapies: an IQ Consortium Industry Position Paper.

Interest and efforts to use recombinant adeno-associated viruses (AAV) as gene therapy delivery tools to treat disease have grown exponentially. However, gaps in understanding of the pharmacokinetics/pharmacodynamics (PK/PD) and disposition of this modality exist. This position paper comes from the Novel Modalities Working Group (WG), part of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ). The pan-industry WG effort focuses on the nonclinical PK and clinical pharmacology aspects of AAV gene therapy and related bioanalytical considerations.Traditional PK concepts are generally not applicable to AAV-based therapies due to the inherent complexity of a transgene-carrying viral vector, and the multiple steps and analytes involved in cell transduction and transgene-derived protein expression. Therefore, we explain PK concepts of biodistribution of AAV-based therapies and place key terminologies related to drug exposure and PD in the proper context. Factors affecting biodistribution are presented in detail, and guidelines are provided to design nonclinical studies to enable a stage-gated progression to Phase 1 testing. The nonclinical and clinical utility of transgene DNA, mRNA, and protein analytes are discussed with bioanalytical strategies to measure these analytes. The pros and cons of qPCR vs. ddPCR technologies for DNA/RNA measurement and qualitative vs. quantitative methods for transgene-derived protein are also presented. Last, best practices and recommendations for use of clinical and nonclinical data to project human dose and response are discussed. Together, the manuscript provides a holistic framework to discuss evolving concepts of PK/PD modeling, bioanalytical technologies, and clinical dose selection in gene therapy.

Inflammatory mechanisms in ischemic stroke: therapeutic approaches.

Acute ischemic stroke is the third leading cause of death in industrialized countries and the most frequent cause of permanent disability in adults worldwide. Despite advances in the understanding of the pathophysiology of cerebral ischemia, therapeutic options remain limited. Only recombinant tissue-plasminogen activator (rt-PA) for thrombolysis is currently approved for use in the treatment of this devastating disease. However, its use is limited by its short therapeutic window (three hours), complications derived essentially from the risk of hemorrhage, and the potential damage from reperfusion/ischemic injury. Two important pathophysiological mechanisms involved during ischemic stroke are oxidative stress and inflammation. Brain tissue is not well equipped with antioxidant defenses, so reactive oxygen species and other free radicals/oxidants, released by inflammatory cells, threaten tissue viability in the vicinity of the ischemic core. This review will discuss the molecular aspects of oxidative stress and inflammation in ischemic stroke and potential therapeutic strategies that target neuroinflammation and the innate immune system. Currently, little is known about endogenous counterregulatory immune mechanisms. However, recent studies showing that regulatory T cells are major cerebroprotective immunomodulators after stroke suggest that targeting the endogenous adaptive immune response may offer novel promising neuroprotectant therapies.

Statins and clinical outcome of acute ischemic stroke: a systematic review.

BACKGROUND: Statin therapy is considered an effective measure for the prevention of ischemic stroke. Several recent studies have indicated that treatment with statins, prior to the onset of acute ischemic stroke, may also substantially reduce the severity of stroke and the degree of patient disability. The purpose of the present review is to systematically evaluate the effectiveness of statin pretreatment on functional outcome of acute ischemic stroke and to assess potential adverse events associated with statin use. METHODS: Relevant articles on the role of statins in acute ischemic stroke were identified via MEDLINE/PubMed, EMBASE, CENTRAL, and by manual searches of the references of identified papers. Clinical studies (most were prospective cohort studies) assessing statin therapy for acute ischemic stroke were selected for the review. Only two randomized controlled clinical trials met the criteria to be included in the analysis. Clinical outcome was assessed based on the degree of disability determined with the modified Rankin Scale (mRS) and Barthel index (BI). The National Institutes of Health Stroke Scale (NIHSS) was used to measure stroke severity. Recurrence of stroke in patients who had suffered from a previous stroke was analyzed with and without statin therapy. Incidence and severity of adverse reactions was reviewed. Because there were too many differences in study outcome measures, a quantitative analysis of data was deemed inappropriate. A qualitative summary of the data was consequently completed. RESULTS: Thirteen reports were systematically reviewed to evaluate the efficacy and safety of statins in the pretreatment of acute ischemic stroke. Pretreatment with statins was found to reduce the recurrence of stroke and to result in more favorable outcomes for patients. The beneficial effects of prior statin therapy in acute ischemic stroke were shown to be especially profound in whites, diabetics, elderly patients with hypertension and other vascular diseases, and in patients with ideal low density lipoprotein (LDL) levels. There were few incidences of adverse reactions with statin pretreatment, most of which were not statistically significant. CONCLUSIONS: Pretreatment with statins was associated with a favorable outcome in acute ischemic stroke, with few incidences of adverse reactions.