We reported previously that Mater is a maternal effect gene that is required for early embryonic development beyond the two-cell stage in mice. Here we show the expressional profile of Mater and its protein during oogenesis and embryogenesis as well as its subcellular localization in oocytes. Mater mRNA was detectable earliest in oocytes of type 2 follicles, whereas MATER protein appeared earliest in oocytes of type 3a primary follicles. Both mRNA and protein accumulated during oocyte growth. In situ hybridization showed that Mater mRNA appeared progressively less abundant in oocytes beyond type 5a primary follicles. By ribonuclease protection assay, Mater mRNA was abundant in germinal vesicle oocytes, but was undetectable in all stages of preimplantation embryos. In contrast, the protein persisted throughout preimplantation development. Immunogold electron microscopic analysis revealed that MATER was located in oocyte mitochondria and nucleoli, and close to nuclear pores. Taken together, our data indicate that Mater gene transcription and protein translation are active during oogenesis, but appear inactive during early embryogenesis. Thus, Mater and its protein are expressed in a manner typical of maternal effect genes. The presence of MATER protein in mitochondria and nucleoli suggests that it may participate in both cytoplasmic and nuclear events during early development.

Extrapolation can be used to address challenges in pediatric drug development. This review describes how these challenges could be addressed by further evolution of quantitative frameworks (i.e., model-based/informed drug discovery and development) and regulatory science in support of pediatric drug development. Included are examples of diseases/indications where extrapolation has been used in different ways as a basis for identifying gaps in the framework and opportunities for continued advancement of pediatric drug development.

The pharmacokinetics, safety, and tolerability of a single dose of moxifloxacin were characterized in 31 pediatric patients already receiving antibiotics for a suspected or proven infection in an open-label phase 1 study. A dosing strategy for each age cohort (Cohort 1: ࣙ6 years to ࣘ14 years; Cohort 2: ࣙ2 years to <6 years; Cohort 3: >3 month to <2 years) was developed using physiology-based pharmacokinetic modeling combined with a stepwise dosing scheme to obtain a similar exposure to adults receiving 400 mg of moxifloxacin. Doses, adjusted to body weight and age, were gradually escalated from 5 mg/kg in Cohort 1 to 10 mg/kg in Cohort 3 based on interim analysis of the pharmacokinetic and safety data. Plasma and urine samples before and after the 60-minute infusion were collected for the analysis of moxifloxacin and its metabolites using a validated high-pressure liquid chromatography assay with tandem mass spectrometry. Moxifloxacin and metabolite concentrations in plasma were within the ranges observed in adults;however,clearance of all analytes was lower in pediatric patients compared with adults.Population pharmacokinetic analyses using the achieved exposure levels in the 3 age cohorts (with known body weight and clearance) predicted similar efficacy and safety profiles to adults. Moxifloxacin was well tolerated in all pediatric age cohorts. Adverse events related to moxifloxacin were mild or moderate in intensity and showed no correlation with increased weight-adjusted doses. Our findings guided the selection of age-appropriate clinical doses for a subsequent phase 3 clinical trial in pediatric patients with complicated intra-abdominal infections.

Background: Gene therapy for hemophilia A has the potential to reduce the treatment burden for care-providers and patients, by eliminating the need for regular factor VIII (FVIII) prophylaxis through the long-term expression of endogenous FVIII at levels sufficient to provide bleed protection. BAY 2599023 (AAVhu37FVIII) is a non-replicating adeno-associated virus (AAV) vector, based on the AAV serotype hu37, which contains a single-stranded DNA genome encoding a B-domain deleted FVIII, under the control of a liver-specific promotor/enhancer combination optimized for transgenic expression. The AAVhu37 capsid is a member of the hepatotropic Clade E family and has been selected based on nonclinical studies demonstrating efficient liver-directed FVIII gene transfer, favorable biodistribution as well as durable FVIII expression. BAY 2599023 is the first clinical-stage AAV gene therapy vector based on the AAVhu37 serotype. This analysis reports safety and FVIII activity following a single intravenous infusion of BAY 2599023 in the first-dose cohort of a phase I/II open-label, first time in human dose-finding study (NCT03588299) of previously treated, severe hemophilia A patients. Patients/Methods: Two participants were enrolled sequentially; each received a single infusion of AAVhu37 (0.5 x 1013 GC/kg). Patients were males ≥18 years with no history of FVIII inhibitor development, no detectable immunity to the AAVhu37 capsid, and >150 exposure days to FVIII products. Primary endpoints were adverse events (AEs), serious AEs and AEs/SAEs of special interest (S/AESI); the secondary endpoint was change in FVIII activity from baseline. Informed patient consent, and ethics committee approval at each local site, were obtained. Results: Following more than 15 weeks of safety observation, no SAEs, AEs related to study drug, nor S/AESI were reported. Liver enzymes (alanine aminotransferase and aspartate aminotransferase) remained <1.5 of baseline. Corticosteroids were not used in either patient. Clear evidence of FVIII expression was observed in both patients with stable values of ~5% and ~17% in the first and second patient, respectively. An early read-out also indicated hemostatic efficacy in both; the first patient had successfully halted prophylaxis for 6 weeks, while the second one, treated on-demand with 99 bleeds recorded in the 12 months prior to gene transfer, has been bleed free for over 5.5 months to date. Conclusions: BAY 2599023 was previously shown in non-clinical studies to have a good safety profile, with the potential to achieve endogenous expression of FVIII at therapeutic levels, over an extended period of time. In this first-in-human clinical study with BAY 2599023, two patients have been treated with BAY 2599023 at the starting dose of 0.5 x 1013 GC/kg and no safety concerns have been reported to date. Measurable expression of endogenous FVIII and an early read-out of hemostatic efficacy have been demonstrated in both patients. Overall, data generated from this first dose cohort demonstrate that successful translation from pre-clinical to clinical development and proof-of-mechanism for BAY 2599023 was achieved. Disclosures Pipe: HEMA Biologics: Consultancy; Shire: Consultancy; Roche/Genentech: Consultancy; Sanofi: Consultancy; Freeline: Consultancy; Apcintex: Consultancy; Novo Nordisk: Consultancy; Catalyst Bioscience: Consultancy; CSL Behring: Consultancy; Bayer: Consultancy; uniQure: Consultancy; BioMarin: Consultancy; Pfizer: Consultancy; Spark Therapeutics: Consultancy. Becka:Bayer: Employment. Detering:Bayer: Employment. Vanevski:Bayer: Employment. Lissitchkov:Octapharma: Equity Ownership, Research Funding; Bayer: Consultancy, Equity Ownership, Honoraria, Other: Principal investigator for clinical trials, Research Funding; Sobi: Consultancy, Equity Ownership, Honoraria; Sanofi: Equity Ownership, Research Funding; Roche: Consultancy, Equity Ownership, Honoraria, Speakers Bureau; Shire: Consultancy, Equity Ownership, Honoraria, Speakers Bureau. OffLabel Disclosure: Gene therapy for haemophilia treatment.