Design and Preclinical Development of TransCon PTH, an Investigational Sustained-Release PTH Replacement Therapy for Hypoparathyroidism.

Hypoparathyroidism (HP) is a condition of parathyroid hormone (PTH) deficiency leading to abnormal calcium and phosphate metabolism. The mainstay of therapy consists of vitamin D and calcium supplements, as well as adjunct Natpara (PTH(1-84)). However, neither therapy optimally controls urinary calcium (uCa) or significantly reduces the incidence of hypercalcemia and hypocalcemia. TransCon PTH, a sustained-release prodrug of PTH(1-34) in development for the treatment of HP, was designed to overcome these limitations. To determine the pharmacokinetics and pharmacodynamics of TransCon PTH, single and repeat s.c. dose studies were performed in rats and monkeys. TransCon PTH demonstrated a half-life of 28 and 34 hours in rats and monkeys, respectively. After repeated dosing, an infusion-like profile of the released PTH, characterized by low peak-to-trough levels, was obtained in both species. In intact rats and monkeys, daily subcutaneous administration of TransCon PTH was associated with increases in serum calcium (sCa) levels and decreases in serum phosphate levels (sP). In monkeys, at a single dose of TransCon PTH that increased sCa levels within the normal range, a concurrent decrease in uCa excretion was observed. In 4-week repeat-dose studies in intact rats and monkeys, uCa excretion was comparable to controls across all dose levels despite increases in sCa levels. Further, in a rat model of HP, TransCon PTH normalized sCa and sP levels 24 hours per day. This was in contrast to only transient trends toward normalization of sCa and sP levels with an up to 6-fold higher molar dose of PTH(1-84). After repeated dosing to HP rats, uCa excretion transiently increased, corresponding to increases in sCa above normal range, but at the end of the treatment period, uCa excretion was generally comparable to sham controls. TransCon PTH was well tolerated and the observed pharmacokinetics and pharmacodynamics were in line with the expected action of physiological replacement of PTH. © 2019 American Society for Bone and Mineral Research.

Fluorescence anisotropy assay for the traceless kinetic analysis of protein digestion.

A novel fluorescence polarization assay based on the natural fluorophore epicocconone has been developed. This assay allows the rapid and accurate determination of enzyme kinetic parameters as well as inhibition constants through the measurement of fluorescence anisotropy on the actual substrate of the protease. It takes advantage of epicocconone's ability to reversibly react with proteins to form an internal charge-transfer complex that is highly fluorescent. The protein-substrate is labeled in situ without the need for prior incubation and/or derivatization steps, which saves time and effort compared to methods employing specifically labeled protein-substrates. The assay can be carried out in 96- or 384-well plates, making it suitable for high-throughput applications in drug development and biotechnology.

Structural optimization of thiourea-based bifunctional organocatalysts for the highly enantioselective dynamic kinetic resolution of azlactones.

This article describes the synthesis of a library of structurally diverse bifunctional organocatalysts bearing both a quasi-Lewis acidic (thio)urea moiety and a Brønsted basic tertiary amine group. Sequential modification of the modular catalyst structure and subsequent screening of the compounds in the alcoholytic dynamic kinetic resolution (DKR) of azlactones revealed valuable structure-activity relationships. In particular, a "hit-structure" was identified which provides e.g.N-benzoyl-tert-leucine allyl ester in an excellent enantiomeric excess of 95%.

Second-generation organocatalysts for the highly enantioselective dynamic kinetic resolution of azlactones.

Bifunctional organocatalysts of the thiourea-tert-amine type, carrying two "matched" elements of chirality, effect the alcoholytic dynamic kinetic resolution of a variety of azlactones with up to 95% ee.