Effect of Various Dosing Schedules on the Pharmacokinetics of Oral Semaglutide: A Randomised Trial in Healthy Subjects.

BACKGROUND: Prescribing information instructs taking oral semaglutide (a glucagon-like peptide-1 analogue) in the fasting state, followed by a post-dose fasting period of ≥ 30 min. This trial compared the recommended dosing schedule with alternative schedules. METHODS: This was a randomised, single-centre, multiple-dose, open-label, five-armed, parallel-group trial in healthy subjects who received once-daily oral semaglutide (3 mg for 5 days followed by 7 mg for 5 days). Subjects (n = 156) were randomised to five dosing schedules: 2-, 4-, or 6-h pre-dose fast followed by a 30-min post-dose fast (treatment arms: 2 h-30 min, 4-30 min, 6 h-30 min); 2-h pre-dose fast followed by an overnight post-dose fast (treatment arm: 2 h-night); or overnight pre-dose fast followed by a 30-min post-dose fast (reference arm: night-30 min). Semaglutide plasma concentration was measured regularly until 24 h after the 10th dose. Endpoints included area under the semaglutide plasma concentration-time curve during a 24-h interval after the 10th dose (AUC0-24h) (primary endpoint) and maximum observed semaglutide plasma concentration after the 10th dose (Cmax) (secondary endpoint). RESULTS: Compared with an overnight pre-dose fast (reference arm: night-30 min), shorter pre-dose fasting times in the 2 h-night, 2 h-30 min, 4 h-30 min, and 6 h-30 min treatment arms resulted in significantly lower semaglutide AUC0-24h and Cmax after the 10th dose (estimated treatment ratio ranges: 0.12-0.43 and 0.11-0.44, respectively; p < 0.0001 for all comparisons). Semaglutide AUC0-24h and Cmax after the 10th dose were similar for the 2 h-30 min and 2 h-night treatment arms. CONCLUSION: This trial supports dosing oral semaglutide in accordance with prescribing information, which requires dosing in the fasting state. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04513704); registered August 14, 2020.

Oral semaglutide is a human glucagon-like peptide-1 analogue that has been approved for the treatment of type 2 diabetes. It has been established that taking oral semaglutide with food or large volumes of water decreases absorption of the drug in the body. Current prescribing information instructs taking oral semaglutide on an empty stomach (known as the fasting state), with 120 mL/4 oz of water, then waiting for at least 30 min before consuming any food, water, or taking other oral medications. This study investigates whether different dosing schedules for oral semaglutide could potentially offer more flexibility to patients in the timing of their oral semaglutide dosing. The trial, conducted in healthy volunteers, compares the dosing schedule described in the prescribing information with different fasting times before (pre-dose) and after (post-dose) taking oral semaglutide during the day or evening, to see if there were any effects on the concentration of drug in the body. Compared to the recommended overnight fasting period, shorter pre-dose fasting periods of 2­6 h with a 30-min post-dose fast considerably reduced semaglutide exposure in the body. Similarly, semaglutide exposure was also reduced with a 2-h pre-dose fast combined with post-dose overnight fasting. These findings further support the current prescribing information, which states that patients should take their oral semaglutide dose after an overnight fast.

Characterization of AN317, a novel selective agonist of α6ß2-containing nicotinic acetylcholine receptors.

Neuronal nicotinic acetylcholine receptors (nAChRs) are crucial mediators of central presynaptic, postsynaptic, and extrasynaptic signaling, and they are implicated in a range of CNS disorders. The numerous nAChR subtypes are differentially expressed and mediate distinct functions throughout the CNS, and thus there is considerable interest in developing subtype-selective nAChR modulators, both for use as pharmacological tools and as putative therapeutics. α6ß2-containing (α6ß2*) nAChRs are highly expressed in and regulate the activity of midbrain dopaminergic neurons, which makes them attractive drug targets in several psychiatric and neurological diseases, including nicotine addiction and Parkinson's disease. This paper presents the preclinical characterization of AN317, a novel α6ß2* agonist exhibiting functional selectivity toward other nAChRs, including α4ß2, α3ß4 and α7 receptors. AN317 induced [3H]dopamine release from rat striatal synaptosomes and augmented dopaminergic neuron activity in substantia nigra pars compacta brain slices in Ca2+ imaging and electrophysiological assays. In line with this, AN317 alleviated the high-frequency tremors arising from reserpine-mediated dopamine depletion in rats. Finally, AN317 mediated significant protective effects on cultured rat mesencephalic neurons treated with the dopaminergic neurotoxin MPP+. AN317 displays good bioavailability and readily crosses the blood-brain barrier, which makes it a unique tool for both in vitro and in vivo studies of native α6ß2* receptors in the nigrostriatal system and other dopaminergic pathways. Altogether, these findings highlight the potential of selective α6ß2* nAChR activation as a treatment strategy for symptoms and possibly even deceleration of disease progression in neurodegenerative diseases such as Parkinson's disease.

Characterization of AN6001, a positive allosteric modulator of α6ß2-containing nicotinic acetylcholine receptors.

α6ß2-Containing nicotinic acetylcholine receptors (α6ß2* nAChRs) are predominantly expressed in midbrain dopaminergic neurons, including substantia nigra pars compacta (SNc) neurons and their projections to striatal regions, where they regulate dopamine release and nigrostriatal activity. It is well established that nAChR agonists exert protection against dopaminergic neurotoxicity in cellular assays and parkinsonian animal models. Historically, drug development in the nAChR field has been mostly focused on development of selective agonists and positive allosteric modulators (PAMs) for the predominant neuronal nAChRs, α7 and α4ß2. Here, we report the discovery and characterization of AN6001, a novel selective α6ß2* nAChR PAM. AN6001 mediated increases in both nicotine potency and efficacy at the human α6/α3ß2ß3V9'S nAChR in HEK293 cells, and it positively modulated ACh-evoked currents through both α6/α3ß2ß3V9'S and a concatenated ß3-α6-ß2-α6-ß2 receptor in Xenopus oocytes, displaying EC50 values of 0.58 µM and 0.40 µM, respectively. In contrast, the compound did not display significant modulatory activity at α4ß2, α3ß4, α7 and muscle nAChRs. AN6001 also increased agonist-induced dopamine release from striatal synaptosomes and augmented agonist-induced global cellular responses and inward currents in dopaminergic neurons in SNc slices (measured by Ca2+ imaging and patch clamp recordings, respectively). Finally, AN6001 potentiated the neuroprotective effect of nicotine at MPP+-treated primary dopaminergic neurons. Overall, our studies demonstrate the existence of allosteric sites on α6ß2* nAChRs and that positive modulation of native α6ß2* receptors strengthens DA signaling. Hence, AN6001 represents an important tool for studies of α6ß2* nAChRs and furthermore underlines the therapeutic potential in these receptors in Parkinson's disease.

α-Conotoxin VnIB from Conus ventricosus is a potent and selective antagonist of α6ß4* nicotinic acetylcholine receptors.

α6-containing (α6*) nicotinic acetylcholine receptors (nAChRs) are expressed throughout the periphery and the central nervous system and constitute putative therapeutic targets in pain, addiction and movement disorders. The α6ß2* nAChRs are relatively well studied, in part due to the availability of target specific α-conotoxins (α-Ctxs). In contrast, all native α-Ctxs identified that potently block α6ß4 nAChRs exhibit higher potencies for the closely related α6ß2ß3 and/or α3ß4 subtypes. In this study, we have identified a novel peptide from Conus ventricosus with pronounced selectivity for the α6ß4 nAChR. The peptide-encoding gene was cloned from genomic DNA and the predicted mature peptide, α-Ctx VnIB, was synthesized. The functional properties of VnIB were characterized at rat and human nAChRs expressed in Xenopus oocytes by two-electrode voltage clamp electrophysiology. VnIB potently inhibited ACh-evoked currents at rα6ß4 and rα6/α3ß4 nAChRs, displayed ∼20-fold and ∼250-fold lower potencies at rα3ß4 and rα6/α3ß2ß3 receptors, respectively, and exhibited negligible effects at eight other nAChR subtypes. Interestingly, even higher degrees of selectivity were observed for hα6/α3ß4 over hα6/α3ß2ß3 and hα3ß4 receptors. Finally, VnIB displayed fast binding kinetics at rα6/α3ß4 (on-rate t½â€¯= 0.87 min-1, off-rate t½â€¯= 2.7 min-1). The overall preference of VnIB for ß4* over ß2* nAChRs is similar to the selectivity profiles of other 4/6 α-Ctxs. However, in contrast to previously identified native α-Ctxs targeting α6* nAChRs, VnIB displays pronounced selectivity for α6ß4 nAChRs over both α3ß4 and α6ß2ß3 receptors. VnIB thus represents a novel molecular probe for elucidating the physiological role and therapeutic properties of α6ß4* nAChRs.