Types A and B Niemann-Pick disease (NPD) result from the deficient activity of acid sphingomyelinase (ASM). An animal model of NPD has been created by gene targeting. In affected animals, the disease followed a severe, neurodegenerative course and death occurred by eight months of age. Analysis of these animals showed their tissues had no detectable ASM activity, the blood cholesterol levels and sphingomyelin in the liver and brain were elevated, and atrophy of the cerebellum and marked deficiency of Purkinje cells was evident. Microscopic analysis revealed 'NPD cells' in reticuloendothelial organs and characteristic NPD lesions in the brain. Thus, the ASM deficient mice should be of great value for studying the pathogenesis and treatment of NPD, and for investigations into the role of ASM in signal transduction and apoptosis.

Proximal tubule cells (PTCs), which are the primary site of kidney injury associated with ischemia or nephrotoxicity, are the site of oligonucleotide reabsorption within the kidney. We exploited this property to test the efficacy of siRNA targeted to p53, a pivotal protein in the apoptotic pathway, to prevent kidney injury. Naked synthetic siRNA to p53 injected intravenously 4 h after ischemic injury maximally protected both PTCs and kidney function. PTCs were the primary site for siRNA uptake within the kidney and body. Following glomerular filtration, endocytic uptake of Cy3-siRNA by PTCs was rapid and extensive, and significantly reduced ischemia-induced p53 upregulation. The duration of the siRNA effect in PTCs was 24 to 48 h, determined by levels of p53 mRNA and protein expression. Both Cy3 fluorescence and in situ hybridization of siRNA corroborated a short t 1 ⁄2 for siRNA. The extent of renoprotection, decrease in cellular p53 and attenuation of p53-mediated apoptosis by siRNA were dose-and time-dependent. Analysis of renal histology and apoptosis revealed improved injury scores in both cortical and corticomedullary regions. siRNA to p53 was also effective in a model of cisplatininduced kidney injury. Taken together, these data indicate that rapid delivery of siRNA to proximal tubule cells follows intravenous administration. Targeting siRNA to p53 leads to a dose-dependent attenuation of apoptotic signaling, suggesting potential therapeutic benefit for ischemic and nephrotoxic kidney injury.

We report the toxicological and pharmacokinetic properties of the synthetic, small interfering RNA I5NP following intravenous administration in rodents and nonhuman primates. I5NP is designed to act via the RNA interference (RNAi) pathway to temporarily inhibit expression of the pro-apoptotic protein p53 and is being developed to protect cells from acute ischemia/reperfusion injuries such as acute kidney injury that can occur during major cardiac surgery and delayed graft function that can occur following renal transplantation. Following intravenous administration, I5NP was very rapidly cleared from plasma was distributed predominantly to the kidney, with very low levels in liver and other tissues. Doses of 800 mg/kg I5NP in rodents, and 1,000 mg/kg I5NP in nonhuman primates, were required to elicit adverse effects, which in the monkey were isolated to direct effects on the blood that included a sub-clinical activation of complement and slightly increased clotting times. In the rat, no additional adverse effects were observed with a rat analogue of I5NP, indicating that the effects likely represent class effects of synthetic RNA duplexes rather than toxicity related to the intended pharmacologic activity of I5NP. Taken together, these data support clinical testing of intravenous administration of I5NP for the preservation of renal function following acute ischemia/reperfusion injury.

PF-04523655 showed a dose-related tendency for improvement in BCVA in DME patients. Studies of higher doses are planned to determine the optimal efficacious dose of PF-04523655. PF-04523655 may offer a new mode of therapeutic action in the management of DME. (ClinicalTrials.gov number, NCT00701181.).

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Background To evaluate the safety, tolerability, pharmacokinetics, and dose-

IntroductionPatients undergoing on-pump cardiac surgery are at an increased risk of acute kidney injury. QPI-1002, a small interfering ribonucleic acid, is under clinical development for the prevention of acute kidney injury. The safety, tolerability, and pharmacokinetics of QPI-1002 was evaluated in this first-in-man, Phase 1 study of a small, interfering ribonucleic acid in patients at risk of acute kidney injury after on-pump cardiac surgery.MethodsIn this phase 1 randomized, placebo-controlled dose-escalation study, a single i.v. dose of QPI-1002 was administered in subjects undergoing on-pump cardiac surgery. Subjects received placebo (n = 4), or QPI-1002 in increasing doses of 0.5 mg/kg (n = 3), 1.5 mg/kg (n = 3), 5 mg/kg (n = 3), and 10 mg/kg (n = 3).ResultsA total of 16 subjects were enrolled in the study. The average maximum concentration and area under the curve from the time of dosing to the last measurable concentration of QPI-1002 were generally dose proportional, indicating that exposure increased with increasing dose. The average mean residence time (mean residence time to the last measurable concentration) was 10 to 13 minutes in all 4 drug-dosing cohorts. Adverse events occurred at a similar rate in all study groups. Of the total 109 reported adverse events, the events were distributed as 26 in the placebo group and 21, 19, 24, and 19 in the QPI-1002 0.5, 1.5, 5.0, and 10.0 mg/kg groups, respectively. Eight of the 16 subjects experienced at least 1 serious adverse event: 4 (100%) in the placebo group and 4 (33.3%) in the combined QPI-1002 cohorts.DiscussionQPI-1002 was rapidly eliminated from plasma. QPI-1002 was safe and well tolerated across all dose groups. Overall, no dose-limiting toxicities or safety signals were observed in the study. Further development of QPI-1002 for prophylaxis of acute kidney injury is warranted.

Types A and B Niemann-Pick disease (NPD) result from the deficient activity of acid sphingomyelinase (ASM). Currently, no treatment is available for either form of NPD. Using the ASM knockout (ASMKO) mouse model, we evaluated the effects of ex vivo hematopoietic stem cell gene therapy on the NPD phenotype. Thirty-two newborn ASMKO mice were preconditioned with low dose radiation (200 cGy) and transplanted with ASMKO bone marrow cells which had been transduced with an ecotropic retroviral vector encoding human ASM. Engraftment of donor-derived cells ranged from 15 to 60% based on Y-chromosome in situ hybridization analysis of peripheral white blood cells, and was achieved in 92% of the transplanted animals. High levels of ASM activity (up to five-fold above normal) were found in the engrafted animals for up to 10 months after transplantation, and their life-span was extended from a mean of 5 to 9 months by the gene therapy procedure. Biochemical and histological analysis of tissues obtained 4-5 months after