Opicapone (Ongentys®), a potent, oral, third-generation, long-acting, peripheral catechol-O-methyltransferase (COMT) inhibitor, is approved as the adjunctive treatment to levodopa (L-Dopa)/dopa-decarboxylase inhibitor (DDCI) therapy in adults with Parkinson's disease (PD) and end-of-dose motor fluctuations who cannot be stabilized on those combinations. Opicapone is a hydrophilic 1,2,4-oxadiazole analog with a pyridine N-oxide at position 3, with these modifications enhancing its potency and extending its duration of action, whilst avoiding cell toxicity. In preclinical animal studies, Opicapone-induced inhibition of peripheral (but not central) COMT activity was associated with a prolonged increase in systemic and central exposure to L-Dopa, with a corresponding reduction in 3-OMD exposure. Following single or multiple doses of Opicapone (5–1200 mg) in healthy adult volunteers or patients with PD, Opicapone inhibited COMT activity in ex vivo erythrocyte assays in a reversible dose-dependent manner, with the duration of Opicapone-induced COMT inhibition independent of dose. Adjunctive Opicapone was generally well tolerated during more than a year of treatment in BIPARK I and BIPARK II (double-blind plus extension phases). The recommended dosage is 50 mg once daily, which should be taken at bedtime at least 1 h before or after L-Dopa combinations.

Selumetinib (AZD6244 or ARRY-142886) is a potent, selective, and ATP-uncompetitive inhibitor of Ras-Raf-mitogen-activated protein kinase kinase (MEK1/2). This inhibition can prevent ERK activation, disrupt downstream signal transduction, and inhibit cancer cell proliferation and survival. Selumetinib has shown tumour suppressive activity in multiple rodent models of human cancer including melanoma, pancreatic, colon, lung, and breast cancers. AstraZeneca is responsible for development and commercialization of selumetinib.

Bremelanotide (formerly PT-141) was developed for the treatment of female sexual dysfunction, hemorrhagic shock, and reperfusion injury. Bremelanotide, a synthetic peptide analog of α-melanocyte-stimulating hormone (α-MSH) is an agonist at melanocortin receptors including the MC3R and MC4R, which are expressed primarily in the central nervous system. Bremelanotide originally was tested for intranasal administration in treating female sexual dysfunction but this application was temporarily discontinued in 2008 after concerns were raised over adverse side effects of increased blood pressure. It appears that development for hemorrhagic shock and reperfusion injury has been discontinued. Palatin Technologies licensed North American development and commercialization rights of bremelanotide to Amag in January 2017. In June 2018, the US Food and Drug Administration (FDA) accepted AMAG Pharmaceuticals’ new drug application for bremelanotide for treatment of hypoactive sexual desire disorder in premenopausal women. If approved, bremelanotide will be available as a self-administered, disposable subcutaneous auto-injector used in anticipation of a sexual encounter.

ODM-201 (also known as BAY-1841788) is a non-steroidal antiandrogen, specifically, a full and high-affinity antagonist of the androgen receptor (AR), that is under development by Orion and Bayer HealthCare for the treatment of advanced, castration-resistant prostate cancer (CRPC). ODM-201 appears to negligibly cross the blood-brain-barrier. This is beneficial due to the reduced risk of seizures and other central side effects from off-target GABAA receptor inhibition that tends to occur in non-steroidal antiandrogens that are structurally similar to enzalutamide. Moreover, in accordance with its lack of central penetration, ODM-201 does not seem to increase testosterone levels in mice or humans, unlike other non-steroidal antiandrogens. Another advantage is that ODM-201 has been found to block the activity of all tested/well-known mutant ARs in prostate cancer, including the recently-identified clinically-relevant F876L mutation. ODM-201 has been studied in phase I and phase II clinical trials and has thus far been found to be effective and well-tolerated, with the most commonly reported side effects including fatigue, nausea, and diarrhea. No seizures have been observed.

ADX-N05, originally discovered by SK Holdings, is a selective dopamine and norepinephrine reuptake inhibitor (DNRI). ADX-N05 (Solriamfetol, sold under the brand name Sunosi) is approved in the US and is under regulatory review in the EU to improve wakefulness in adult patients with hypersomnia associated with narcolepsy or obstructive sleep apnoea.The US FDA has approved solriamfetol (Sunosi, Jazz Pharmaceuticals) for the treatment of excessive daytime sleepiness in adults with narcolepsy or obstructive sleep apnea.The dual-acting dopamine and norepinephrine reuptake inhibitor is approved for narcolepsy in once-daily 75 mg and 150 mg doses, and in obstructive sleep apnea in once-daily 37.5 mg, 75 mg, and 150 mg doses.

Siponimod (BAF312) is a dual agonist at the sphingosine-1 phosphate receptors, S1PR1 and S1PR5. The S1P receptor is commonly found on the surface of specific cells residing in the central nervous system (CNS), that are responsible for causing CNS damage that drives loss of function in secondary progressive multiple sclerosis (SPMS). Siponimod (BAF312) enters the brain and by binding to these specific receptors, may prevent the activation of these harmful cells, helping to reduce the loss of physical and cognitive function associated with SPMS.

Pitolisant (INN) or tiprolisant (USAN) is a histamine receptor inverse agonist/antagonist selective for the H3 subtype. It has stimulant and nootropic effects in animal studies and may have several medical applications, having been researched for the treatment of narcolepsy, for which it has been granted orphan drug status in the EU and US. It is currently in clinical trials for schizophrenia and Parkinson’s disease. Pitolisant hydrochloride was approved by European Medicine Agency (EMA) on Mar 31, 2016. It was developed and marketed as Wakix® by Bioprojet in EU. Wakix® is available as the tablet for oral use, containing 4.5 mg and 18 mg of Pitolisant hydrochloride. The initial dose of 9 mg (two 4.5 mg, tablets) per day, and it should be used at the lowest effective dose, depending on individual patient response and tolerance, according to an up-titration scheme, without exceeding the dose of 36 mg/day. Pitolisant was the first clinically used H3 receptor inverse agonist.

Lemborexant is a dual orexin receptor antagonist, which inhibits orexin by binding competitively to two subtypes of orexin receptors. During normal periods of sleep, orexin system activity is suppressed, suggesting it is possible to purposefully facilitate the initiation and maintenance of sleep by interfering with orexin neurotransmission with lemborexant. Extensive in vitro and non-clinical testing of lemborexant supported the supposition that lemborexant has a low risk of QT prolongation at therapeutic and supratherapeutic exposures in humans. A Phase III study of lemborexant in insomnia is underway, and in addition, Eisai has announced the initiation of Phase II clinical studies of lemborexant in patients with irregular sleep-wake rhythm disorder.

LASMIDITAN is a serotonin (5-HT) receptor agonist without vasoconstrictor activity, which selectively binds to the 5-HT(1F) receptor subtype. It is under development for the treatment of migraine.

Lofexidine is newly FDA approved in the United States under the brand name LUCEMYRA for the treatment of opioid withdrawal symptoms in adults. Lofexidine acts as an agonist to α2 adrenergic receptors. These receptors inhibit adenylyl cyclase activity, leading to the inhibition of the second messenger, cyclic adenosine monophosphate (cAMP). The inhibition of cAMP leads to potassium efflux through calcium-activated channels, blocking calcium ions from entering the nerve terminal, resulting in suppression of neural firing, inhibition of norepinephrine release. Lofexidine replaces the opioid-driven inhibition of cAMP production and moderating the symptoms of opioid withdrawal.