Validation of an ultrasensitive LC-MS/MS method for PTH 1-34 in porcine plasma to support a solid dose PK study.

BACKGROUND: The bioanalysis of Teriparatide (PTH 1-34) is extremely challenging due to the low plasma concentrations present at a therapeutic level. An LC-MS/MS-based method was developed that detected PTH 1-34 at 15 pg/ml in porcine plasma, and was validated using the bioanalytical method validation guidelines. RESULTS: The analytical methodology demonstrated good linearity over a range of 15-1000 pg/ml, and demonstrated good precision and accuracy. The validated method was used to support a trial comparing a solid state dose to a solution-based injection (Forteo™). CONCLUSION: The ability to quantify the peptide at low pg/ml in porcine plasma demonstrates that it is possible to develop very sensitive LC-MS/MS-based methodologies to support the bioanalysis of large peptide biotherapeutics.

Privacy-preserving GWAS analysis on federated genomic datasets.

BACKGROUND: The biomedical community benefits from the increasing availability of genomic data to support meaningful scientific research, e.g., Genome-Wide Association Studies (GWAS). However, high quality GWAS usually requires a large amount of samples, which can grow beyond the capability of a single institution. Federated genomic data analysis holds the promise of enabling cross-institution collaboration for effective GWAS, but it raises concerns about patient privacy and medical information confidentiality (as data are being exchanged across institutional boundaries), which becomes an inhibiting factor for the practical use. METHODS: We present a privacy-preserving GWAS framework on federated genomic datasets. Our method is to layer the GWAS computations on top of secure multi-party computation (MPC) systems. This approach allows two parties in a distributed system to mutually perform secure GWAS computations, but without exposing their private data outside. RESULTS: We demonstrate our technique by implementing a framework for minor allele frequency counting and χ2 statistics calculation, one of typical computations used in GWAS. For efficient prototyping, we use a state-of-the-art MPC framework, i.e., Portable Circuit Format (PCF) 1. Our experimental results show promise in realizing both efficient and secure cross-institution GWAS computations.

In vitro and in vivo stability and pharmacokinetic profile of unacylated ghrelin (UAG) analogues.

Ghrelin, an endocrine hormone predominantly produced by the stomach, exists in acylated and unacylated forms in the circulation. Unacylated ghrelin (UAG), the more abundant form in blood, possesses similar, independent or opposite physiological actions as acylated ghrelin (AG). AZP502, a linear 8-amino acid peptide from the central region of UAG (UAG(6-13)), and its full (AZP531) and partially (AZP533) cyclised derivatives, exhibit the same pharmacological profile as UAG both in vitro and in vivo, independently of AG receptor binding. We investigated the stability of these three fragments in vitro in human blood samples and in vivo after subcutaneous and intravenous injection in rats and dogs using liquid chromatography-mass spectrometry. In both species, AZP502 is rapidly degraded generating two major metabolites. Partial cyclisation of AZP502 and acylation at its N-terminus (AZP533 peptide) improves its stability in human plasma in vitro. Full cyclisation of AZP502 (AZP531 peptide) also completely protects the peptide from peptidase degradation in vitro in human blood samples. Moreover this cyclisation strongly improves the stability and the bioavailability of this peptide in vivo in both dogs and rats (mean bioavailability of 10-15% and 85-95% for AZP502 and AZP531 respectively). Taken together these results support the rationale for developing AZP531 as a long-acting UAG analogue for subcutaneous injection for the treatment of type 2 diabetes mellitus and other metabolic disorders.