Genome editing holds the potential for curative treatments of human disease, however, clinical realization has proven to be a challenging journey with incremental progress made up until recently. Over the last decade, advances in clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems have provided the necessary breakthrough for genome editing in the clinic. The progress of investigational CRISPR therapies from bench to bedside reflects the culmination of multiple advances occurring in parallel, several of which intersect with clinical pharmacology and translation. Directing the CRISPR therapy to the intended site of action has necessitated novel delivery platforms, and this has resulted in special considerations for the complete characterization of distribution, metabolism, and excretion, as well as immunogenicity. Once at the site of action, CRISPR therapies aim to make permanent alterations to the genome and achieve therapeutically relevant effects with a single dose. This fundamental aspect of the mechanism of action for CRISPR therapies results in new considerations for clinical translation and dose selection. Early advances in model-informed development of CRISPR therapies have incorporated key facets of the mechanism of action and have captured hallmark features of clinical pharmacokinetics and pharmacodynamics from phase I investigations. Given the recent emergence of CRISPR therapies in clinical development, the landscape continues to evolve rapidly with ample opportunity for continued innovation. Here, we provide a snapshot of selected topics in clinical pharmacology and translation that has supported the advance of systemically administered in vivo and ex vivo CRISPR-based investigational therapies in the clinic.
An increased incidence of renal tubular adenomas and carcinomas was identified in the 2-year CD-1 mouse carcinogenicity study with empagliflozin (sodium-glucose transporter 2 inhibitor) in high dose (1,000 mg/kg/day) male mice. A 13-week mouse renal investigative pathogenesis study was conducted with empagliflozin to evaluate dose dependency and temporal onset of nonneoplastic degenerative/regenerative renal tubular and molecular (genes, pathways) changes which precede neoplasia. Male and female CD-1 mice were given daily oral doses of 0, 100, 300, or 1,000 mg/kg/day (corresponding carcinogenicity study dose levels) for 1, 2, 4, 8, or 13 weeks. The maximum expected pharmacology with secondary osmotic diuresis was observed by week 1 at ≥100 mg/kg/day in both genders. Histopathologic kidney changes were first detected after 4 weeks of dosing in the male 1,000 mg/kg/day dose group, with progressive increases in the incidence and/or number of findings in this dose group so that they were more readily detected during weeks 8 and 13. Changes detected starting on week 4 consisted of minimal single-cell necrosis and minimal increases in mitotic figures. These changes persisted at an increased incidence at weeks 8 and 13 and were accompanied by minimal to mild tubular epithelial karyomegaly, minimal proximal convoluted tubular epithelial cell hyperplasia, and a corresponding increase in Ki-67-positive nuclei in epithelial cells of the proximal convoluted tubules. There were no corresponding changes in serum chemistry or urinalysis parameters indicative of any physiologically meaningful effect on renal function and thus these findings were not considered to be adverse. Similar changes were not identified in lower-dose groups in males nor were they present in females of any dose group. RNA-sequencing analysis revealed male mouse-specific changes in kidney over 13 weeks of dosing at 1,000 mg/kg/day. Treatment-related changes included genes and pathways related to p53-regulated cell cycle and proliferation, transforming growth factor β, oxidative stress, and renal injury and the number of genes with significant expression change dramatically increased at week 13. These treatment-related changes in genes and pathways were predominant in high-dose males and complemented the observed temporal renal tubular changes. Overall, these mouse investigative study results support the role of early empagliflozin-related degenerative/regenerative changes only observed in high-dose male CD-1 mice as a key contributing feature to a nongenotoxic mode of renal tumor pathogenesis.
May 9, 2019April 9, 2019Free AccessAdjusting neurofilament light levels using an MRI-based estimate of total axonal bulk improves its prediction of MS progression (P5.2-004)Jonathan Phillips, Ruturaj Masvekar, Peter Kosa, Kayla Jackson, Ann Weideman, and Bibiana BielekovaAuthors Info & AffiliationsApril 9, 2019 issue92 (15_supplement) Letters to the Editor
Abstract Physical forces play an essential role in life. Stimulating living cells or tissues with mechanical cues can conjure a myriad of biochemical and biophysical responses. [1,2,3] It is well known that mechanical cues, such as gravity, are important in proper tissue development and maintenance. [4] Likewise, mechanical cues have proven to be essential when engineering living tissue. [5] It has been shown that giving mechanical input to engineered load-bearing tissues will often result in a product more closely resembling the native tissue. [5,6] In contrast, studies done in the microgravity environment of outer space have shown that a loss of the constant mechanical input of gravity will result in loss of tissue mass. [7,8,9] Tissue engineering in microgravity systems has also resulted in “mechanically inferior” tissue. [10] It is now know that feedback from cellular mechanoreceptors is critical for proper development, maintenance, and remodeling of tissues. Actual mechanisms and biochemical pathways involved in mechanotransduction have not been fully elucidated and are subjects of intensifying research.
Abstract Objective Serum neurofilament light chain (sNFL) is becoming an important biomarker of neuroaxonal injury. While sNFL correlates with cerebrospinal fluid NFL (cNFL), 40-60% of variance remains unexplained. Assuming that for diseases of the central nervous system (CNS), such as multiple sclerosis (MS), the cNFL better reflects CNS injury, our goal was to develop and validate adjustment of sNFL for relevant confounders, to strengthen cNFL-sNFL correlations. Methods We used 1,378 matched cNFL-sNFL pairs divided into training and validation cohort with matching data on 11 confounders, neuroexam, and magnetic resonance imaging (MRI). The effect of confounders on cNFL-sNFL relationship was tested using multiple linear regression (MLR) model. Propensity score matching was used to identify effect of spinal cord damage on sNFL levels. Results In the training cohort (n=898) we correlated 11 confounders with the residuals from cNFL-sNFL linear regression. Four non-overlapping confounders explaining highest proportion of variance (12%: age, 8.7%: blood urea nitrogen, 3%: alkaline phosphatase, and 3.9%: weight) were used in MLR model. The model strengthened the cNFL-sNFL correlation from R 2 = 0.52 to 0.64 in the independent validation cohort and strengthened correlation of adjusted sNFL with number of contrast-enhancing lesions (from R 2 0.11 to 0.18). However, only sNFL, but not cNFL correlated with MS severity outcomes. Using propensity score matching, we demonstrated that subjects with proportionally higher sNFL to cNFL levels have significantly higher clinical and radiological evidence of spinal cord injury. Interpretation Superiority of sNFL likely resides in the release of NFL from axons of lower motor or dorsal ganglia neurons directly to blood.
Although histopathology is considered the gold standard for assessing testicular toxicity in the nonclinical setting, identification of noninvasive biomarkers for testicular injury are desirable to improve safety monitoring capabilities for clinical trials. Inhibin B has been investigated as a noninvasive biomarker for testicular toxicity. This study investigates the correlation of Inhibin B in Wistar Han rats with the onset and reversibility of testicular histopathology from classical testicular toxicants carbendazim, cetrorelix acetate (CTX), and 1,2-dibromo-3-chloropropane (DBCP). The dose regimen included Interim (day 8), Drug (day 29), and nondosing Recovery (day 58) Phases. Inhibin B was not effective at predicting the onset of carbendazim- or CTX-mediated testicular pathology in rats. Inhibin B was reduced by DBCP administration at the end of the Drug Phase only, acting as a leading indicator of the onset of testicular toxicity before the onset of germ cell depletion. However, since Inhibin B was only decreased at the end of the Dosing Phase and not at the Recovery Phase, when the onset of testicular pathology occurred, it is unclear if monitoring Inhibin B would provide sufficient advanced warning for the onset of testicular pathology. Furthermore, follicle stimulating hormone was decreased following CTX and DBCP administration in the Interim Phase and CTX in the Drug Phase. Inhibin B has limited predictive capacity as a leading testicular biomarker in rats.
Women with a sonographic short cervix in the mid-trimester are at increased risk for preterm delivery. This study was undertaken to determine the efficacy and safety of using micronized vaginal progesterone gel to reduce the risk of preterm birth and associated neonatal complications in women with a sonographic short cervix.
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