0760 SUVN-G3031, A Potent And Selective Histamine H3 Receptor Inverse Agonist: Safety, Tolerability And Pharmacokinetics Following Single And Multiple Ascending Doses In Healthy Adult Subjects

Introduction

SUVN-G3031 is a potent and selective histamine H3 receptor inverse agonist currently being developed for the treatment of narcolepsy. SUVN-G3031 produced robust wake promoting and anticataplectic effects in animal model relevant to the disease. This supports its therapeutic utility in the treatment of sleep related disorders like narcolepsy with and without cataplexy.

Methods

Two Phase 1 studies were conducted to assess safety, tolerability and pharmacokinetics (PK) of SUVN-G3031. In the first study, single ascending doses of 0.1 mg to 20 mg SUVN-G3031 were administered to healthy subjects. For multiple ascending dose cohorts, doses of 1 mg to 6 mg were administered for 14 days. In the second Phase 1 study, effects of food, gender and age on the PK of SUVN-G3031 were assessed.

Results

SUVN-G3031 absorbed rapidly following single oral administration and the exposures (Cmax and AUC) were dose proportional at the tested doses between 0.1 mg to 20 mg. SUVN-G3031 attained steady state on day six and achieved projected efficacy concentrations following repeated administrations. Food, gender and age had no effect on pharmacokinetics of SUVN-G3031. SUVN-G3031 was well tolerated up to 20 mg/ day single dose and 6 mg repeated dose in healthy adult subjects. There were no serious adverse events reported by any subject during Phase 1 studies.

Conclusion

SUVN-G3031 was well tolerated in humans with adequate plasma exposures for efficacy and has favorable pharmacokinetics suitable for once a day oral administration. SUVN-G3031 is currently being evaluated in a Phase 2 study as monotherapy for the treatment of narcolepsy with and without cataplexy (ClinicalTrials.gov Identifier: NCT04072380).

Support

None

0155 SUVN-G3031, A Potent and Selective Histamine H3 Receptor Inverse Agonist - Differentiating Features Over Current Treatments of Narcolepsy

Introduction

Majority of pharmacological agents used in the treatment of narcolepsy have several limitations. Both nonclinical and clinical evidences suggest usefulness of the histamine H3 receptor (H3R) inverse agonists for the treatment of narcolepsy and addressing several of the current limitations.

Methods

Extensive nonclinical studies were carried out for SUVN-G3031 and other pharmacological agents that are currently being used for the treatment of narcolepsy. Nonclinical parameters like inter-species binding affinity, selectivity profile, in vivo and in vitro ADME features, nonclinical efficacy, neurochemistry and safety were compared.

Results

SUVN-G3031 has no inter-species variation in binding affinity at H3R with less than 50% inhibition at 1 µM against 70 other targets. Unlike pitolisant, SUVN-G3031 has no significant binding affinity at sigma 1 and 2 receptor. SUVN-G3031 has no inhibition and induction liability towards major CYP enzymes and transporters. Pitolisant is reported to be a CYP3A4, CYP2B6, and CYP1A2 inducer and a CYP2D6 and OCT1 inhibitor. SUVN-G3031 has robust wake promoting effects. SUVN-G3031 showed negligible affinity towards hERG channel with IC50 > 10 µM and had no effects on any ECG parameters in dog telemetry study. SUVN-G3031 did not show convulsion in rats up to the tested dose of 100 mg/kg, p.o. Most of the pharmacological agents used for the treatment of narcolepsy have abuse liability; SUVN-G3031 produced no change in the striatal and accumbal dopamine levels in rats suggesting no propensity to induce abuse liability. Unlike competing H3R inverse agonists, SUVN-G3031 has no effects on fertility and embryo-fetal development up to the highest tested doses.

Conclusion

Nonclinical studies demonstrate superiority of SUVN-G3031 over pharmacological agents currently used in the treatment of narcolepsy. SUVN-G3031 is being evaluated in a Phase 2 study as monotherapy for the treatment of narcolepsy with and without cataplexy (ClinicalTrials.gov Identifier: NCT04072380).

Support

None

0072 Preclinical Characterization of SUVN-G3031, a Histamine H3 Receptor Inverse Agonist for the Treatment of Narcolepsy

Introduction

Narcolepsy is a chronic sleep disorder characterized by overwhelming daytime drowsiness, sudden attacks of sleep and sometimes accompanied by cataplexy. Although the orexin deficiency is considered to be the primary cause of this disorder, lot of attention has been focused recently on targeting histaminergic neurotransmission by blockade of histamine H3 receptor (H3R). SUVN-G3031 is one of the potent and selective H3R inverse agonist currently being evaluated in a Phase 2 study as monotherapy for the treatment of narcolepsy with and without cataplexy (ClinicalTrials.gov Identifier: NCT04072380).

Methods

Binding of SUVN-G3031 in human and rat histamine H3R was evaluated in in vitro radioligand binding assay and functionality was assessed in GTPγS assay. Pharmacokinetic properties were evaluated after oral administration in rat and dog. Neurotransmitters like histamine, dopamine and norepinephrine were estimated in rat cortex using microdialysis.

Results

SUVN-G3031 is an inverse agonist at histamine H3R with hKi of 8.7 nM and showed minimal binding against over 70 target sites. SUVN-G3031 exhibited desired pharmacokinetic properties in rat and dog with excellent brain penetration in rats. SUVN-G3031 produced significant increase in histamine, dopamine and norepinephrine levels in cortex. SUVN-G3031 produced no change in the striatal and accumbal dopamine levels in rats, suggesting no propensity to induce abuse liability. SUVN-G3031 blocked R-α-methylhistamine induced water intake and produced dose dependent increase in tele-methylhistamine levels in various brain regions and in cerebrospinal fluid of male Wistar rats.

Conclusion

SUVN-G3031 is an inverse agonist at histamine H3 receptor and results from the preclinical studies presented here provide a strong evidence for the potential utility of SUVN-G3031 in the treatment of narcolepsy with and without cataplexy.

Support

None

0759 Phase 2 Proof Of Concept Study Of SUVN-G3031, A Histamine H3 Receptor Inverse Agonist For The Potential Treatment Of Narcolepsy

Introduction

SUVN-G3031 is a potent inverse agonist at histamine H3 receptor (H3R) with selectivity over 70 other targets. SUVN-G3031 has excellent pharmacokinetics in rats and dogs. SUVN-G3031 demonstrated dose dependent receptor occupancy in rats with marked wake-promoting and anticataplectic effects in orexin knockout mice supporting its potential therapeutic utility in the treatment of narcolepsy. Long-term safety studies in animals and Phase 1 evaluation for safety, tolerability and pharmacokinetics demonstrated no concern for further development of SUVN-G3031.

Methods

SUVN-G3031 is currently being evaluated in a Phase 2 proof of concept study in USA for the treatment of narcolepsy with and without cataplexy (ClinicalTrials.gov Identifier: NCT04072380). This is a double-blind, placebo-controlled, parallel-group, multicenter study to evaluate the safety, tolerability, pharmacokinetics and efficacy of SUVN-G3031 in comparison to placebo in patients with narcolepsy with and without cataplexy. Participants with an ESS score of ≥ 12; and mean MWT time of < 12 min are being randomized at a ratio of 1:1:1 to 2 mg SUVN-G3031, 4 mg SUVN-G3031 or placebo. Patients are to be stratified based on the type of narcolepsy. Each patient will receive study drug once daily for 14 days. The primary objective of the study is to evaluate the effectiveness of SUVN-G3031 compared to placebo as measured by an improvement in the maintenance of wakefulness test (MWT) score. Various secondary, exploratory, safety endpoints and steady state plasma concentrations will be evaluated.

Results

This study has been initiated in Q3 2019 and subject recruitment is expected to be completed by Q2 2020.

Conclusion

This study is a phase 2 clinical trial evaluating the efficacy and safety of SUVN-G3031 as a monotherapy in patients with narcolepsy with and without cataplexy. Safety and efficacy results from the study are expected in Q3 2020.

Support

None

0008 SUVN-G3031, A Histamine H3 Receptor Inverse Agonist Produces Robust Wake Promoting and Anticataplectic Activity in Orexin Knockout Mice

Introduction

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness, sleep paralysis, hallucinations, and in some cases episodes of cataplexy. Results from animal studies indicate the involvement of deficient orexin transmission in narcolepsy which can be circumvented by the activation of histaminergic neurons. SUVN-G3031 is a potent and selective histamine H3 receptor inverse agonist with hKi of 8.7 nM and shows less than 50% inhibition at 1 µM against 70 other targets. SUVN-G3031 exhibited excellent pharmacokinetic properties and brain penetration in preclinical species. Oral administration of SUVN-G3031 produces significant increase in histamine, dopamine and norepinephrine levels in the rat cortex. Long-term safety studies in animals have been successfully completed without any concern for further development of SUVN-G3031. In the present study, the effects of SUVN-G3031 were evaluated in orexin knockout mice, a reliable animal model of narcolepsy as a proof-of-concept study for the treatment of narcolepsy with and without cataplexy.

Methods

Male orexin knockout mice (10 - 15 weeks old, 25 - 35 g at the time of surgery) were implanted with telemetric device for simultaneous monitoring of electroencephalography (EEG) and electromyography. Animals were allowed surgical recovery of 3 weeks prior to EEG recording. Effects of SUVN-G3031 (3 and 10 mg/kg, p.o.) were evaluated during active period of animals.

Results

SUVN-G3031 produced significant increase in wakefulness with concomitant decrease in non-rapid eye movement sleep in orexin knockout mice. SUVN-G3031 also significantly decreased the number of cataplectic episodes in orexin knockout mice.

Conclusion

Results from the current preclinical study provide a strong basis for the utility of SUVN-G3031 for the treatment of narcolepsy with and without cataplexy. SUVN-G3031 is currently being evaluated in a Phase 2 study as monotherapy for the treatment of narcolepsy with and without cataplexy (ClinicalTrials.gov Identifier: NCT04072380).

Support

None

Therapeutic Potential of 5-HT6 Antagonist SB399885 in Traumatic Stress Disorder

BACKGROUND

Post-traumatic stress disorder is an anxiety disorder for which current therapies are not effective. The 5-Hydroxytryptamine6 receptor antagonist SB399885 has been reported to have an anxiolytic effect. Hence, the current investigation was undertaken to evaluate its efficacy in post-traumatic stress disorder.

METHODS

Rats were placed in the operant box and given 3 foot shocks at intervals of 1 min. The following day the duration of freezing was recorded. For the enhanced sustained prolonged stress (ESPS), the rats were subjected to various stressors such as restraint stress (2 h), forced swim (20 min), and anesthesia, followed by a foot shock for 4 s. The rats were then subjected to the elevated plus maze.

RESULTS

Treatment with SB399885 (1 and 3 mg/kg, I. p.) was found to significantly decrease the freezing time in the contextual fear conditioning model. Rats subjected to ESPS spent greater time in the open arm of the elevated plus maze when administered SB399885 at the above mentioned doses. The treatment had no effect on locomotor activity. SB399885 decreased the 5-hydroxytryptamine levels in the amygdala at doses that were effective in the above animal models.

CONCLUSION

5-Hydroxytryptamine6 antagonists may hold potential in the treatment of post-traumatic stress.