Half-life prolongation of therapeutic proteins by conjugation to ATIII-binding pentasaccharides: a first-in-human study of CarboCarrier® insulin.

AIM: Conjugation to antithrombin III ATIII-binding pentasaccharides has been proposed as a novel method to extend the half-life of therapeutic proteins. We aim to validate this technological concept in man by performing a first-in-human study using CarboCarrier® insulin (SCH 900948) as an example. A rising single dose phase 1 study was performed assessing safety, tolerability, pharmacokinetics and relative bioactivity of CarboCarrier® insulin. Safety, tolerability and pharmacokinetics (PK) of single doses of CarboCarrier® insulin in healthy volunteers were explored, and the dose-response relationship and relative bioactivity of CarboCarrier® insulin in subjects with type 2 diabetes were investigated. METHODS: After an overnight fast, subjects were randomized to a treatment sequence. PK and pharmacodynamic (glucose, insulin and C-peptide) samples were obtained for up to 72 h post-dose. Effects of CarboCarrier® insulin were compared with those of NPH-insulin. RESULTS: CarboCarrier® insulin was safe and well-tolerated and no consistent pattern of adverse events occurred. CarboCarrier® insulin exposure (Cmax and AUC) increased proportionally with dose. The mean terminal elimination half-life ranged between 3.11 and 5.28 h. All CarboCarrier® insulin dose groups showed decreases in the mean change from baseline of plasma glucose concentrations compared with the placebo group. CONCLUSIONS: CarboCarrier® insulin is pharmacologically active showing features of insulin action in man. The elimination half-life of the molecule was clearly extended compared with endogenous insulin, indicating that conjugation to ATIII-binding pentasaccharides is a viable approach to extend the half-life of therapeutic proteins in humans. This is an important step towards validation of the CarboCarrier® technology by making use of CarboCarrier® insulin as an example.

Dose-dependent effects of UVB-induced skin carcinogenesis in hairless p53 knockout mice.

Exposure to (solar) UVB radiation gives rise to mutations in the p53 tumor suppressor gene that appear to contribute to the earliest steps in the molecular cascade towards human and murine skin cancer. To examine in more detail the role of p53, we studied UVB-induced carcinogenesis in hairless p53 knock-out mice. The early onset of lymphomas as well as early wasting of mice interfered with the development of skin tumors in p53 null-mice. The induction of skin tumors in the hairless p53+/- mice was accomplished by daily exposure to two different UV-doses of approximately 450 J/m2 and 900 J/m2 from F40 lamps corresponding to a fraction of about 0.4 and 0.8 of the minimal edemal dose. Marked differences in skin carcinogenesis were observed between the p53+/- mice and their wild type littermates. Firstly, at 900 J/m2, tumors developed significantly faster in the heterozygotes than in wild types, whereas at 450 J/m2 there was hardly any difference, suggesting that only at higher damage levels loss of one functional p53 allele is important. Secondly, a large portion (25%) of skin tumors in the heterozygotes were of a more malignant, poorly differentiated variety of squamous cell carcinomas, i.e. spindle cell carcinomas, a tumor type that was rarely observed in daily UV exposed wild type hairless mice. Thirdly, the p53 mutation spectrum in skin tumors in heterozygotes is quite different from that in wild types. Together these results support the notion that a point mutation in the p53 gene impacts skin carcinogenesis quite differently than allelic loss: the former is generally selected for in early stages of skin tumors in wild type mice, whereas the latter enhances tumor development only at high exposure levels (where apoptosis becomes more prevalent) and appears to increase progression (to a higher grade of malignancy) of skin tumors.

Effect of sugammadex on QT/QTc interval prolongation when combined with QTc-prolonging sevoflurane or propofol anaesthesia.

BACKGROUND: We evaluated the potential for QT/corrected QT (QTc) interval prolongation after sugammadex given with propofol or sevoflurane anaesthesia. METHODS: This was a two-factorial, randomized, parallel-group study in 132 healthy subjects. Anaesthesia was maintained with sevoflurane or propofol. At ~20 min following sevoflurane/propofol initiation, sugammadex 4 mg/kg or placebo was administered. Neuromuscular blocking agents were not administered. Electrocardiograms were recorded regularly. The primary variable was the time-matched mean difference in the Fridericia-corrected QT interval (QTcF) change from baseline for sugammadex versus placebo when combined with propofol or sevoflurane. No relevant QTcF prolongation was concluded if the upper one-sided 95 % confidence interval (CI) was below the 10 ms margin of regulatory non-inferiority, up to 30 min post-study drug. Blood samples were taken for pharmacokinetic analysis. An exploratory analysis evaluated potential QT/QTc effects of neostigmine 50 µg/kg/glycopyrrolate 10 µg/kg in combination with propofol. RESULTS: The estimated mean QTcF differences between sugammadex and placebo ranged from -2.4 to 0.6 ms when combined with either anaesthetic. The largest upper one-sided 95 % CI for the mean QTcF difference between sugammadex and placebo was 2 ms, occurring 2 min post-dosing. Propofol and sevoflurane resulted in mean QTcF increases exceeding 10 and 30 ms, respectively. On top of these prolongations, the effect of sugammadex was negligible at all timepoints. The mean peak sugammadex concentration was 66.5 µg/mL, with exposure similar in the sevoflurane/propofol groups. The mean QTcF changes from baseline following neostigmine/glycopyrrolate in 10 healthy subjects ranged between -1.4 and 3.6 ms. CONCLUSION: Sugammadex 4 mg/kg does not cause clinically relevant QTc interval prolongation versus placebo when combined with propofol or sevoflurane.

Mechanism of action of a nanomolar potent, allosteric antagonist of the thyroid-stimulating hormone receptor.

BACKGROUND AND PURPOSE: Graves' disease (GD) is an autoimmune disease in which the thyroid is overactive, producing excessive amounts of thyroid hormones, caused by thyroid-stimulating hormone (TSH) receptor-stimulating immunoglobulins (TSIs). Many GD patients also suffer from thyroid eye disease (Graves' ophthalmopathy or GO), as TSIs also activate TSH receptors in orbital tissue. We recently developed low molecular weight (LMW) TSH receptor antagonists as a novel therapeutic strategy for the treatment of GD and GO. Here, we determined the molecular pharmacology of a prototypic, nanomolar potent LMW TSH receptor antagonist, Org 274179-0. EXPERIMENTAL APPROACH: Using CHO cells heterogeneously expressing human TSH receptors and rat FRTL-5 cells endogenously expressing rat TSH receptors, we determined the potency and efficacy of Org 274179-0 at antagonizing TSH- and TSI-induced TSH receptor signalling and its cross-reactivity at related follicle-stimulating hormone and luteinizing hormone receptors. We analysed the allosteric mode of interaction of Org 274179-0 and determined whether it is an inverse agonist at five naturally occurring, constitutively active TSH receptor mutants. KEY RESULTS: Nanomolar concentrations of Org 274179-0 completely inhibited TSH (and TSI)-mediated TSH receptor activation with little effect on the potency of TSH, in accordance with an allosteric mechanism of action. Conversely, increasing levels of TSH receptor stimulation only marginally reduced the antagonist potency of Org 274179-0. Org 274179-0 fully blocked the increased basal activity of all the constitutively active TSH receptor mutants tested with nanomolar potencies. CONCLUSIONS AND IMPLICATIONS: Nanomolar potent TSH receptor antagonists like Org 274179-0 have therapeutic potential for the treatment of GD and GO.