TAAR1 ( EC50 = 0.140 μM ); 5-HT_1A Receptor ( EC50 = 2.3 μM ); 5-HT_1B Receptor ( EC50 = 15.6 μM ); 5-HT_1D Receptor ( EC50 = 0.262 μM ); 5-HT_2A Receptor ( EC50 > 10 μM ); 5-HT_2C Receptor ( EC50 = 30 μM ); 5-HT₇ Receptor ( EC50 = 6.7 μM )

SEP-856 (10 μM) exhibits >50% inhibition of specific binding at α_2A, α_2B, D₂, 5-HT_1A, 5-HT_1B, 5-HT_1D, 5-HT_2A, 5-HT_2B, 5-HT_2C, and 5-HT₇ receptors[1].

SEP-856 (0.3, 1 and 10 mg/kg, i.p.) has a behavioral signature resembling that of well-known antipsychotic medications and is CNS active[1].
SEP-856 (0.3, 1 and 10 mg/kg, orally once) substantially lowers hyperactivity brought on by PCP[1]. When SEP-856 is taken orally at doses of 1, 3, and 10 mg/kg, there is a dose-dependent reduction in REM sleep, an increase in REM sleep latency, and an increase in cumulative wake time [1].

In Vitro and In Vivo 5-HT1A and D2 Receptor Occupancy Studies.[1]
In vitro autoradiography was used to determine the effects of SEP-856 on [3H]-8-OH-DPAT binding to 5-HT1A receptors in rat brain sections. In vivo occupancy of SEP-856 at D2 receptors was measured with [3H]-raclopride in Sprague-Dawley rats and with [18F]-fallypride–positron emission tomography in nonhuman primates. For details, refer to Supplemental Material.[1]

---

In Vitro Pharmacology.[1]
The in vitro pharmacology of SEP-856 at known receptors and enzymes was assessed in broad panel screens. For those targets at which SEP-856 (10 μM) demonstrated greater than 50% inhibition, dose–response curves were generated and inhibitory constant values were determined. Incubation conditions and additional details for equilibrium radioligand binding are listed in the Supplemental Material.[1]
The functional (both agonist and antagonist) effects were also determined. Assays used to study the functional effects were as follows: Intracellular cAMP levels were determined for 5-HT1A, 5-HT7, TAAR1, and D2, using either the DiscoveRx HitHunter cAMP XS+ assay or the Homogenous Time-Resolved Fluorescence (HTRF) cAMP assay. The 5-HT1A was also studied using GTPγS binding. Impedance was used for 5-HT1B, 5-HT1D, and α2A. Intracellular Ca2+ release was used for 5-HT2A and 5-HT2C. Inositol monophosphate (IP1) accumulation was used for 5-HT2B. D2 was also studied using the DiscoveRx PathHunter β-arrestin recruitment assay.

Patch–Clamp Recordings in the Dorsal Raphe Nucleus and Ventral Tegmental Area.[1]
In vitro whole–cell patch–clamp recording techniques were used in isolated slice preparations (male C57BL/6J mice, 4–16 weeks) of the dorsal raphe nucleus (DRN) and ventral tegmental area (VTA) to investigate the effects of SEP-856 on neuronal activity. The experiments examined the effects of SEP-856 (1–30 μM) on the activity of DRN and VTA neurons that were characterized by their electrophysiological properties and/or their sensitivity to application of the 5-HT1A receptor agonist 8-OH-DPAT (DPAT; 10 μM). Subsequently, effects mediated via the TAAR1 and/or via the 5-HT1A receptor were investigated using the selective antagonist N-(3-Ethoxy-phenyl)-4-pyrrolidin-1-yl-3-trifluoromethyl-benzamide (EPPTB; 0.05–1 μM) and the selective antagonist WAY-100635 (WAY-635; 10 μM), respectively. All compounds were dissolved in either DMSO or ddH2O and diluted with artificial cerebrospinal fluid (aCSF) to a final concentration from a minimum 1000-fold higher stock concentration (maximum slice DMSO concentration 0.1%). Whole–cell patch–clamp recordings were performed at room temperature using the blind version of the patch–clamp technique with either Axopatch 1D or Multiclamp 700B amplifiers. For detailed methods, refer to the Supplemental Material.[1]

---

In Vivo Extracellular Single–Unit Recordings in the DRN.[1]
In vivo extracellular single–unit recordings were used to characterize the effects of SEP-856 on firing of DRN neurons in anesthetized, male Sprague-Dawley rats. Following surgery and insertion of the recording electrode, baseline firing activity of the neuron was recorded for at least 10 minutes prior to the compound administration. SEP-856 was tested at 1, 2, and 5 mg/kg by i.v. injection. After clear inhibitory effects were observed (3–5 minutes after compound administration), WAY-100635 (80 µg/kg, i.v.) was given to determine whether it could antagonize the inhibitory effect of SEP-856. Blood samples were taken 30 minutes following compound administration. For additional details, refer to the Supplemental Material.

Acute treatment with phencyclidine (PCP), which induces robust hyperactivity in rodents
0.3, 1 and 3 mg/kg
Orally once.

---

EEG Recordings.[1]
EEG recordings were performed in seven adult male Sprague-Dawley rats using a crossover design. Animals were implanted with chronic recording devices for continuous recordings of electroencephalograph (EEG), electromyograph, core body temperature (Tb), and locomotor activity via telemetry (DQ ART 4.1 software; Data Sciences, St. Paul, MN). Following completion of the data collection, expert scorers determined states of sleep and wakefulness in 10-second epochs by examining the recordings visually using NeuroScore software (Data Sciences). All doses of SEP-856, caffeine, and vehicle were administered by oral gavage. A minimum of 3 days elapsed between doses. To evaluate the effects of SEP-856 on sleep/wake parameters during the inactive period, dosing occurred during the middle of the rats’ normal inactive period. The first 6 hours of the recording were scored and analyzed. For additional details, please refer to the Supplemental Material.[1]

---

In Vivo Microdialysis.[1]
Extracellular dopamine and serotonin levels were assessed in the prefrontal cortex and dorsal striatum using in vivo microdialysis in freely moving Sprague-Dawley rats. For detailed methods, please refer to the Supplemental Material.

---

In Vivo Pharmacokinetics Studies.[1]
Details on in vivo pharmacokinetic measurements are provided in the Supplemental Material.

[1]. SEP-363856, a Novel Psychotropic Agent with a Unique, Non-D2 Receptor Mechanism of Action. J Pharmacol Exp Ther. 2019 Oct;371(1):1-14.

For the past 50 years, the clinical efficacy of antipsychotic medications has relied on blockade of dopamine D2 receptors. Drug development of non-D2 compounds, seeking to avoid the limiting side effects of dopamine receptor blockade, has failed to date to yield new medicines for patients. In this work, we report the discovery of SEP-363856 (SEP-856), a novel psychotropic agent with a unique mechanism of action. SEP-856 was discovered in a medicinal chemistry effort utilizing a high throughput, high content, mouse-behavior phenotyping platform, in combination with in vitro screening, aimed at developing non-D2 (anti-target) compounds that could nevertheless retain efficacy across multiple animal models sensitive to D2-based pharmacological mechanisms. SEP-856 demonstrated broad efficacy in putative rodent models relating to aspects of schizophrenia, including phencyclidine (PCP)-induced hyperactivity, prepulse inhibition, and PCP-induced deficits in social interaction. In addition to its favorable pharmacokinetic properties, lack of D2 receptor occupancy, and the absence of catalepsy, SEP-856's broad profile was further highlighted by its robust suppression of rapid eye movement sleep in rats. Although the mechanism of action has not been fully elucidated, in vitro and in vivo pharmacology data as well as slice and in vivo electrophysiology recordings suggest that agonism at both trace amine-associated receptor 1 and 5-HT1A receptors is integral to its efficacy. Based on the preclinical data and its unique mechanism of action, SEP-856 is a promising new agent for the treatment of schizophrenia and represents a new pharmacological class expected to lack the side effects stemming from blockade of D2 signaling. SIGNIFICANCE STATEMENT: Since the discovery of chlorpromazine in the 1950s, the clinical efficacy of antipsychotic medications has relied on blockade of dopamine D2 receptors, which is associated with substantial side effects and little to no efficacy in treating the negative and cognitive symptoms of schizophrenia. In this study, we describe the discovery and pharmacology of SEP-363856, a novel psychotropic agent that does not exert its antipsychotic-like effects through direct interaction with D2 receptors. Although the mechanism of action has not been fully elucidated, our data suggest that agonism at both trace amine-associated receptor 1 and 5-HT1A receptors is integral to its efficacy. Based on its unique profile in preclinical species, SEP-363856 represents a promising candidate for the treatment of schizophrenia and potentially other neuropsychiatric disorders.[1]

C9H14CLNOS

219.7316

219.05

C, 49.20; H, 6.42; Cl, 16.13; N, 6.37; O, 7.28; S, 14.59

1310422-41-3

SEP-363856; 1310426-33-5; (Rac)-SEP-363856; 1310426-29-9; 2375116-24-6 (besylate); 2375116-27-9 (mesylate)

139415154

White to off-white solid powder

2

3

2

13

154

1

CNC[C@H]1C2=C(CCO1)C=CS2.Cl

JRDQGVVFSHRVTL-QRPNPIFTSA-N

InChI=1S/C9H13NOS.ClH/c1-10-6-8-9-7(2-4-11-8)3-5-12-9;/h3,5,8,10H,2,4,6H2,1H3;1H/t8-;/m0./s1

1-[(7S)-5,7-dihydro-4H-thieno[2,3-c]pyran-7-yl]-N-methylmethanamine;hydrochloride

Ulotaront; Ulotaront HCl; Ulotaront hydrochloride; SEP 856; SEP-856; SEP856; SEP-363856; SEP 363856; SEP-363856 hydrochloride; SEP-363856 (hydrochloride); SEP-363856 HCl; Ulotaront HCl; ULOTARONT HYDROCHLORIDE; (7S)-4,7-dihydro-N-methyl-5H-thieno[2,3-c]pyran-7-methanamine hydrochloride; 6P8Y2467AU; SEP363856;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O: ~100 mg/mL (~455.1 mM)
DMSO: ~62.5 mg/mL (~284.4 mM)

Solubility in Formulation 1: ≥ 6.25 mg/mL (28.44 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 62.5 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 6.25 mg/mL (28.44 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 62.5 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 6.25 mg/mL (28.44 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 62.5 mg/mL clear DMSO stock solution to 900 μL corn oil and mix evenly.

---

Solubility in Formulation 4: 100 mg/mL (455.10 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

---

 (Please use freshly prepared in vivo formulations for optimal results.)