AZD3293: Pharmacokinetic and Pharmacodynamic Effects in Healthy Subjects and Patients with Alzheimer's Disease.

AZD3293 (LY3314814) is a promising new potentially disease-modifying BACE1 (ß-secretase) inhibitor in Phase III clinical development for the treatment of Alzheimer's disease. Reported here are the first two Phase I studies: (1) a single ascending dose study evaluating doses of 1-750 mg with a food-effect component (n = 72), and (2) a 2-week multiple ascending dose study evaluating doses of 15 or 50 mg once daily (QD) or 70 mg once weekly (QW) in elderly subjects (Part 1, n = 31), and 15, 50, or 150 mg QD in patients with mild to moderate Alzheimer's disease (Part 2, n = 16). AZD3293 was generally well tolerated up to the highest doses given. No notable food effects were observed. PK following multiple doses (Part 2) were tmax of 1 to 3 h and mean t1/2 of 16 to 21 h across the 15 to 150 mg dose range. For single doses of ≥5 mg, a ≥70% reduction was observed in mean plasma Aß40 and Aß42 concentrations, with prolonged suppression for up to 3 weeks at the highest dose level studied. Following multiple doses, robust reductions in plasma (≥64% at 15 mg and ≥78% at ≥50 mg) and cerebrospinal fluid (≥51% at 15 mg and ≥76% at ≥50 mg) Aß peptides were seen, including prolonged suppression even with a QW dosing regimen. AZD3293 is the only BACE1 inhibitor for which prolonged suppression of plasma Aß with a QW dosing schedule has been reported. Two Phase III studies of AZD3293 (AMARANTH, NCT02245737; and DAYBREAK-ALZ, NCT02783573) are now ongoing.

Tolerability in man following inhalation dosing of the selective TLR7 agonist, AZD8848.

BACKGROUND: Many patients with asthma have a T-helper type 2 (Th2) driven inflammation of the lung, whereas toll-like receptor 7 (TLR7) agonists, by inducing type I interferons, inhibit Th2 responses. In man, oral or parenteral TLR7 agonists can induce influenza-like symptoms through systemic induction of type I interferons. Design of a TLR7 agonist that is only active in the lung could reduce the risk of side effects and offer a new means for treating asthma. We developed a TLR7 agonist antedrug, AZD8848, to determine its local and systemic effects in preclinical models and man. METHODS: In vitro cellular potencies for the TLR7 antedrug agonist, AZD8848, were determined along with pharmacokinetics and efficacy in a rat allergy model. Sputum and blood biomarkers were measured in single ascending and multiple ascending dose clinical studies following inhalation delivery of AZD8848 and tolerability assessed. RESULTS: AZD8848 was potent in cellular assays and pharmacokinetics confirmed lack of systemic exposure to AZD8848. Weekly lung dosing in an animal model showed efficacy 26 days beyond the final dose. In healthy volunteers, AZD8848 was initially well tolerated with target engagement being demonstrated by induction of CXCL10 in sputum. A second inhaled dose, given 1 week later, amplified the systemic interferon signal in more than half the participants and resulted in significant influenza-like symptoms. CONCLUSIONS: The antedrug design restricted the direct actions of AZD8848 to the lung. However, the type I interferon induced locally by TLR7 spilled over systemically, limiting the utility of this inhaled antedrug approach. TRIAL REGISTRATION NUMBER: NCT01560234, NCT01818869.

Population pharmacokinetic and pharmacodynamic analysis of plasma Aß40 and Aß42 following single oral doses of the BACE1 inhibitor AZD3839 to healthy volunteers.

Modulating deposition of Aß-containing plaques in the brain may be beneficial in treating Alzheimer's disease. ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitors have been shown to reduce Aß in plasma and CSF in healthy volunteers. In this study safety, pharmacokinetics and pharmacodynamics that is reduction of the plasma biomarkers Aß40 and Aß42 , of the BACE1 inhibitor AZD3839 were evaluated. Single oral ascending doses (1-300 mg) of AZD3839 were administered to 54 young healthy volunteers in a randomized, double-blind, placebo-controlled study. The data was analyzed using non-linear mixed effects modeling. AZD3839 reduced Aß40 and Aß42 in plasma with estimated potencies (EC50 ) of 46 and 59 nM, respectively, and a maximum effect of approximately 55%. This was in excellent agreement with the concentration-response relationships obtained in mouse and guinea pig. AZD3839 exposure displayed non-linear kinetics, described by a three-compartment model with a saturated binding compartment and an increase in bioavailability with dose. AZD3839 was safe, although, a dose-dependent QTcF prolongation was observed (mean 20 milliseconds at 300 mg). In conclusion, AZD3839 reduced plasma Aß40 and Aß42 , demonstrating clinical peripheral proof of mechanism. Pre-clinical models were predictive for the effect of AZD3839 on the human plasma biomarker in a strictly quantitative manner.

Late intervention with a myeloperoxidase inhibitor stops progression of experimental chronic obstructive pulmonary disease.

RATIONALE: Inflammation and oxidative stress are linked to the deleterious effects of cigarette smoke in producing chronic obstructive pulmonary disease (COPD). Myeloperoxidase (MPO), a neutrophil and macrophage product, is important in bacterial killing, but also drives inflammatory reactions and tissue oxidation. OBJECTIVES: To determine the role of MPO in COPD. METHODS: We treated guinea pigs with a 2-thioxanthine MPO inhibitor, AZ1, in a 6-month cigarette smoke exposure model, with one group receiving compound from Smoking Day 1 and another group treated after 3 months of smoke exposure. RESULTS: At 6 months both treatments abolished smoke-induced increases in lavage inflammatory cells, largely ameliorated physiological changes, and prevented or stopped progression of morphologic emphysema and small airway remodeling. Cigarette smoke caused a marked increase in immunohistochemical staining for the myeloperoxidase-generated protein oxidation marker dityrosine, and this effect was considerably decreased with both treatment arms. Serum 8-isoprostane, another marker of oxidative stress, showed similar trends. Both treatments also prevented muscularization of the small intrapulmonary arteries, but only partially ameliorated smoke-induced pulmonary hypertension. Acutely, AZ1 prevented smoke-induced increases in expression of cytokine mediators and nuclear factor-κB binding. CONCLUSIONS: We conclude that an MPO inhibitor is able to stop progression of emphysema and small airway remodeling and to partially protect against pulmonary hypertension, even when treatment starts relatively late in the course of long-term smoke exposure, suggesting that inhibition of MPO may be a novel and useful therapeutic treatment for COPD. Protection appears to relate to inhibition of oxidative damage and down-regulation of the smoke-induced inflammatory response.

E. coli expression and purification of human and cynomolgus IL-15.

The physiological activities of Interleukin-15 (IL-15) suggest that it could be useful as an immunomodulator to activate the innate immune system, however, the expression and purification yields of recombinant mature IL-15 have typically been low. In this report, a method was optimised to generate milligram quantities of this cytokine. Human IL-15 with an N-terminal (His)(6)-tag was expressed in Escherichia coli as an insoluble protein. The IL-15 material was purified from other cellular proteins by dissolution in 6M guanidine HCl, followed by Ni-NTA chromatography in a buffer containing 8M urea. Use of a multi-component screen identified the optimal conditions for folding (His)(6)-tagged human IL-15 and the method was scaled up to produce milligram quantities of folded material in its native conformation, with two intra-molecular disulphides as determined by electrospray mass spectrometry. Mature IL-15 was generated by cleavage with recombinant enterokinase, which was subsequently removed by Ni-NTA chromatography. Identical methods were used to produce mature cynomolgus monkey (Macaca fascicularis) IL-15 in similar quantities. Human and cynomolgus IL-15 were both active in two IL-15 dependent assays; mouse CTLL2 cell proliferation and human and cynomolgus CD69 upregulation on CD3(-) CD8+ lymphocytes in whole blood. Despite being 96% identical at the amino acid level the human IL-15 was 10-fold more potent than the cynomolgus IL-15 in both assays. The methods described here are useful for producing both mature IL-15 proteins in sufficient quantity for in vivo and in vitro studies, including X-ray crystallography.