SSR-125543 is a potent, selective, and orally active corticotropin-releasing factor 1 receptor (CRF1) antagonist (Ki value of 2nM). SSR-125543 attenuates long-term cognitive deficit induced by acute inescapable stress in mice, independently from the hypothalamic pituitary adrenal axis. SSR-125543 prevents stress-induced cognitive deficit associated with hippocampal dysfunction. SSR-125543 had been in phase II clinical trials by Sanofi for the treatment of Post-traumatic stress disorder. It is also in phase I trials for the treatment of anxiety. The compound had also been in phase II clinical trials for the treatment of major depression. However, in 2011, the research was discontinued.

Arimoclomol citrate is an experimental drug developed by a biopharmaceutical company CytRx Corporation. In 2011 the worldwide rights to arimoclomol were bought by Danish biotech company Orphazyme ApS. The European Medicines Agency (EMA) and U.S. Food & Drug Administration (FDA) granted orphan drug designation to arimoclomol as a potential treatment for Niemann-Pick type C in 2014 and 2015 respectively. Arimoclomol is believed to function by stimulating a normal cellular protein repair pathway through the activation of molecular chaperones. Since damaged proteins, called aggregates, are thought to play a role in many diseases, CytRx believes that arimoclomol could treat a broad range of diseases.

Zavegepant is a third generation, small-molecule, calcitonin gene-related peptide (CGRP) receptor antagonist being developed by Pfizer, under a license from Bristol-Myers Squibb, for the prevention and treatment of chronic and episodic migraine. In March 2023, zavegepant nasal spray (ZAVZPRET™) received its first approval in the USA for the acute treatment of migraine with or without aura in adults, based on two randomized, double-blind, placebo-controlled studies. Clinical development of an oral formulation of zavegepant is currently underway.

Nirogacestat (PF-3084014) is a tetralin imidazole gamma-secretase inhibitor. Gamma-secretase, a proteolytic enzyme complex, mediates processing of several integral membrane proteins including amyloid precursor protein and Notch. This compound can inhibit both Notch-related pathway in neoplasia and reduces amyloid-β production. Nirogacestat (PF-3084014) is under development by Pfizer for the treatment of cancer.

Daridorexant (Quviviq™; Idorsia Pharmaceuticals Ltd.) is an orally administered dual orexin type 1 and type 2 (OX1 and OX2) receptor antagonist (DORA) being developed for the treatment of insomnia. It was selected from a pool of drug candidates on the basis of an expected effect duration of ≈ 8 h at a dose of 25 mg, with a half-life intended to minimize residual effects that might impair daytime functioning. Based on the results of two pivotal phase III trials, daridorexant was recently approved in the USA for the treatment of adult patients with insomnia characterized by difficulties with sleep onset and/or sleep maintenance. The mechanism of action of daridorexant in the treatment of insomnia is presumed to be through antagonism of orexin receptors. The orexin neuropeptide signaling system plays a role in wakefulness. Blocking the binding of wake-promoting neuropeptides orexin A and orexin B to receptors OX1R and OX2R is thought to suppress wake drive.

Trofinetide (NNZ 2566), a proprietary small molecule analogue of glycine-proline-glutamate [Glypromate®], is being developed by Neuren Pharmaceuticals and Acadia Pharmaceuticals for the treatment of brain injuries, fragile X syndrome, Rett syndrome. Trofinetide is a synthetic analogue of a naturally occurring neurotrophic peptide derived from IGF-1, a growth factor produced by brain cells. In animal models, trofinetide exhibits a wide range of important effects including inhibiting neuroinflammation, normalizing the role of microglia and correcting deficits in synaptic function. Trofinetide was approved in March 2023 in the USA for the treatment of Rett syndrome in adult and pediatric patients 2 years of age and older.

Ganaxolone (3alpha-hydroxy-3beta-methyl-5alpha-pregnan-20-one) (GNX) is the 3beta-methylated synthetic analog of allopregnanolone; it belongs to a class of compounds referred to as neurosteroids. GNX is an allosteric modulator of GABA(A) receptors acting through binding sites which are distinct from the benzodiazepine binding site. It has activity in a broad range of animal models of epilepsy. GNX has been shown to be well tolerated in adults and children. In early phase II studies, GNX has been shown to have activity in adult patients with partial-onset seizures and epileptic children with history of infantile spasms. It is currently undergoing further development in infants with newly diagnosed infantile spasms, in women with catamenial epilepsy, and in adults with refractory partial-onset seizures. Ganaxolone is a CNS-selective GABAA modulator being developed in three different dose forms (IV, capsule, and liquid) intended to maximize therapeutic reach to adult and pediatric patients in both acute and chronic care settings.Ganaxolone is a synthetic analog of endogenous allopregnanolone, which has been shown to be an effective anticonvulsant by restoring electrical balance to the seizing brain. While allopregnanolone’s anticonvulsant and anti-anxiety activities are well documented, allopregnanolone has the potential to convert back to its metabolic precursor progesterone, which could lead to hormonal side effects. Ganaxolone has been designed with an added methyl group that prevents back conversion to an active steroid which unlocks ganaxolone’s potential for chronic use. In preclinical studies, ganaxolone exhibited potency and efficacy comparable to allopregnanolone. Both ganaxolone and allopregnanolone bind to GABAA at the synaptic and extrasynaptic binding sites. Activity with extrasynaptic GABAA receptors are of particular importance for treating patients who developed tolerance to benzodiazepines and barbiturates. Ganaxolone binds to the GABAA receptors, which opens the pore to allow chloride ions to move into the postsynaptic neuron, leading to the inhibition of neurotransmission.

MK-8031 (also known as Atogepant) is piperidinonylcarboxamideazaindane derivative patented by Merck Sharp & Dohme Corp as CGRP receptor antagonist useful for prevention and treatment of Migraine. A press release in June 2018 announced positive results for MK-8031, in a Phase 2 trial of daily use for episodic migraine prevention. MK-8031appeared to show good efficacy in migraine prevention and no significant liver toxicity signal at any dose despite daily dosing for 3 months. Phase III clinical trial was initiated in 2019 and currently in progress.

Samidorphan, which was developed by Alkermes, is an opioid receptor antagonist that has been co-formulated with olanzapine into a single-dose oral tablet to mitigate the risk of weight gain while providing the therapeutic effect of olanzapine. In June 2021, the Food and Drug Administration (FDA) approved Lybalvi (olanzapine/samidorphan) for indications including treatment of adults with schizophrenia and/or bipolar I disorder (acute manic episodes or acute episodes with mixed features).

Viloxazine is a selective norepinephrine reuptake inhibitor that has a long history of clinical use in Europe as an antidepressant. An immediate-release formulation was approved for the treatment of depression in the UK in 1974, and was subsequently marketed there and in several European countries for 30 years with no major safety concerns. In April of 2021, the United States Food and Drug Administration (FDA) approved the use of viloxazine (QELBREE), developed by Supernus Pharmaceuticals, for the treatment of attention-deficit/hyperactivity disorder (ADHD) in pediatric and adult patients. Approval was based on positive results from a series of short-term phase III clinical trials in which viloxazine improved the severity of ADHD symptoms in children and adolescents with diagnosed ADHD. Viloxazine is available as extended-release capsules for once-daily oral administration.