Palovarotene (R-667, RO-3300074) was developed by Roche Holding AG as a selective retinoic acid receptor gamma agonist for the treatment of emphysema. Phase I clinical trials of palovarotene in patients with emphysema demonstrated that the drug is well tolerated, with improvements observed in markers of emphysema progression. Unlike all-trans retinoic acid, the pharmacokinetic profile of palovarotene appears to be dose-proportional. However, those studies were discontinued. Palovarotene is also being investigated in phase II of the clinical trial in the treatment of Fibrodysplasia Ossificans Progressiva (FOP). Palovarotene received Fast Track designation from the U.S. Food and Drug Administration (FDA) and orphan designations for the treatment of FOP from both the FDA and the European Medicines Agency (EMA).

Gepirone (brand name Travivo) is an investigational azapirone antidepressant and anxiolytic drug in development for the treatment of major depressive disorder but has yet to be marketed. Like other azapirones, it acts as a selective partial agonist of the 5-HT1A receptor. Gepirone has been under development in the U.S. in an extended release form (referred to as Gepirone ER). It has been rejected multiple times by the FDA during the drug approval process and Phase III studies evaluating its use in the treatment of MDD were prematurely terminated. These were the initial Phase III studies of gepirone ER in MDD, and the effective dose range had not been determined. In March 2016, the FDA reversed its decision and gave gepirone ER a positive review, clearing the way for the drug to finally gain market approval in the U.S. In addition to its antidepressant and anxiolytic properties, gepirone has been found to improve symptoms of sexual dysfunction in men and women, similarly to the marketed 5-HT1A receptor agonist flibanserin. The pro-sexual effects appear to be independent of its antidepressant and anxiolytic effects. Mechanism of action studies have demonstrated that gepirone possesses a much greater selectivity for 5-HT1A receptors over dopamine D2 receptors. Long-term studies have shown that gepirone has a differential action at presynaptic (agonist) and post-synaptic (partial agonist) 5-HT1A receptors. Treatment with gepirone ER desensitizes presynaptic 5-HT1A receptors, which decreases serotonin autoregulatory inhibition and enhances activation of postsynaptic 5-HT1A receptors. As a partial agonist gepirone ER acts as an agonist when endogenous serotonin is not present and as an antagonist when endogenous serotonin is present. Overall, gepirone ER increases serotonin production when insufficient amounts are present, and decreases serotonin production when excess amounts are present. Gepirone has been tested in Phase II clinical trial as antidepressant medication for pharmacotherapy for cocaine dependent subjects.

Tauroursodeoxycholic acid (TUDCA) is an endogenous hydrophilic bile acid used clinically to treat certain liver diseases. It is approved in Italy and Turkey for the treatment of cholesterol gallstones and is an investigational drug in China, Unites States, and Italy. Tauroursodeoxycholic acid is being investigated for use in several conditions such as Primary Biliary Cirrhosis (PBC), insulin resistance, amyloidosis, Cystic Fibrosis, Cholestasis, and Amyotrophic Lateral Sclerosis. Tauroursodeoxycholate (TUDC) promote choleresis by triggering the insertion of transport proteins for bile acids into the canalicular and basolateral membranes of hepatocytes. In addition, Tauroursodeoxycholate exerts hepatoprotective and anti-apoptotic effects, can counteract the action of toxic bile acids and reduce endoplasmic reticulum stress. Tauroursodeoxycholate can also initiate the differentiation of multipotent mesenchymal stem cells (MSC) including hepatic stellate cells and promote their development into hepatocyte-like cells. Although the hepatoprotective and choleretic action of TUDC is empirically used in clinical medicine since decades, the underlying molecular mechanisms remained largely unclear.

Remimazolam is an intravenous benzodiazepine sedative-hypnotic with rapid onset and offset of action. This compound undergoes organ-independent metabolism to an inactive metabolite. Like other benzodiazepines, remimazolam can be reversed with flumazenil to rapidly terminate sedation and anesthesia. Phase I and II clinical trials have shown that remimazolam is safe and effective when used for procedural sedation. Phase III clinical trials have been completed investigating efficacy and safety in patients undergoing bronchoscopy and colonoscopy. The developer of this drug has suggested that intensive care unit sedation (beyond 24 hours) could be another possible indication for further development, since it is unlikely that prolonged infusions or higher doses of remimazolam would result in accumulation and extended effect.

Ozanimod (previously known as RPC-1063) is a selective immune-inflammatory modulator of the G protein-coupled receptors sphingosine 1-phosphate 1 and 5, which are part of the sphingosine 1-phosphate (S1P) receptor family. Treatment with S1P receptor modulators interferes with S1P signaling and blocks the response of lymphocytes (a type of white blood cell) to exit signals from the lymph nodes, sequestering them within the nodes. The result is a downward modulation of circulating lymphocytes and anti-inflammatory activity by inhibiting cell migration to sites of inflammation. Ozanimod is currently in phase III clinical trials for the treatment of relapsing multiple sclerosis (RMS) and ulcerative colitis, and also in phase II clinical trials to determine whether it is effective in the treatment of Crohn's disease.

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.

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.

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.

Lusutrombopag (trade name Mulpleta) is an orally bioavailable, small molecule thrombopoietin (TPO) receptor agonist being developed by Shionogi for chronic liver disease (CLD) patients with thrombocytopenia prior to elective invasive surgery. Lusutrombopag acts selectively on the human TPO receptor and activates signal transduction pathways that promote the proliferation and differentiation of bone marrow cells into megakaryocytes, thereby increasing platelet levels. In September 2015, Lusutrombopag received its first global approval in Japan for the improvement of CLD-associated thrombocytopenia in patients scheduled to undergo elective invasive procedures. Oral Lusutrombopag is rapidly absorbed, with a median time to maximum serum concentration (Tmax) of 3.8–4.0 h in healthy subjects administered single doses of oral Lusutrombopag 1, 2 or 4 mg, and 6 h in CLD patients with thrombocytopenia administered oral Lusutrombopag 3 mg once daily for 7 days. The major metabolic pathway for Lusutrombopag appears to be omega- and beta-oxidation. Lusutrombopag is a substrate of breast cancer resistance protein and P-glycoprotein, according to in vitro data.

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.