Rolapitant (VARUBI) is neurokinin 1 (NK1) receptor antagonist. Rolapitant does not have significant affinity for the NK2 or NK3 receptors. Drug is indicated in combination with other antiemetic agents in adults for the prevention of delayed nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including, but not limited to, highly emetogenic chemotherapy. Most common adverse reactions are: neutropenia and hiccups at Cisplatin Based Highly Emetogenic Chemotherapy; decreased appetite, neutropenia and dizziness at Moderately Emetogenic Chemotherapy and Combinations of Anthracycline and Cyclophosphamide. Inhibition of BCRP and P-gp by rolapitant can increase plasma concentrations of the concomitant drug and potential for adverse reactions. Strong CYP3A4 Inducers (e.g., rifampin) can significantly reduce plasma concentrations of rolapitant and decrease the efficacy of VARUBI.

Fosnetupitant is a prodrug form of netupitant. Netupitant is a selective antagonist of human substance P/neurokinin 1 (NK-1) receptors. Upon intravenous administration, fosnetupitant is converted by phosphatases to its active form. It competitively binds to and blocks the activity of NK-1 receptors in the central nervous system, by inhibiting binding of substance P (SP) to NK-1 receptors. This prevents delayed emesis, which is associated with SP secretion. AKYNZEO® is a combination of palonosetron, a serotonin-3 receptor antagonist, and netupitant (capsules for oral use) or fosnetupitant (injections for intravenous use). AKYNZEO® for injection is indicated in combination with dexamethasone in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy.

Aprepitant (brand name: Emend (the brand name used in all English-speaking countries an antiemetic, is a substance P/neurokinin 1 (NK1) receptor antagonist which, in combination with other antiemetic agents, is indicated for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy. Aprepitant has little or no affinity for serotonin (5-HT3), dopamine, and corticosteroid receptors, the targets of existing therapies for chemotherapy-induced nausea and vomiting. Aprepitant has been shown to inhibit emesis induced by cytotoxic chemotherapeutic agents, such as cisplatin, via central actions. Animal and human Positron Emission Tomography (PET) studies with aprepitant have shown that it crosses the blood brain barrier and occupies brain NK1 receptors.

AV608, a 4-aminopiperidine derivative, is a selective, specific, long-acting, orally active and potent nonpeptidic antagonist of the NK-1 receptor. AV-608 had been in phase II clinical trials for the treatment of social phobia and overactive bladder (OAB). This compound was originally discovered by Novartis, and then licensed to Areva Pharmaceuticals in October 2003. Addition this drug was in phase I clinical trial for the treatment of Irritable Bowel Syndrome (IBS), this disease is characterized by chronic abdominal pain and frequent comorbid anxiety. The substance P ⁄ neurokinin-1 receptor system is implicated in the regulation of both pain and anxiety, suggesting a potential therapeutic target in IBS. However, the researches on this drug candidate were discontinued in 2010.

Nolpitantium (SR-140333) is a highly selective nonpeptide antagonist of neurokinin-1 (NK1) receptor. Nolpitantium potently, selectively and competitively inhibited substance P binding to NK1 receptors from various animal species, including humans. In vitro, it was a potent antagonist in functional assays for NK1 receptors such as [Sar9, Met(O2)11]substance P-induced endothelium-dependent relaxation of rabbit pulmonary artery and contraction of guinea-pig ileum. Up to 1 mkM, Nolpitantium had no effect in bioassays for NK2 and NK3 receptors. The antagonism exerted by Nolpitantium toward NK1 receptors was apparently non-competitive, with pD2' values between 9.65 and 10.16 in the different assays. Nolpitantium also blocked in vitro [Sar9, Met(O2)11]substance P-induced release of acetylcholine from rat striatum. In vivo, Nolpitantium exerted highly potent antagonism toward [Sar9, Met(O2)11]substance P-induced hypotension in dogs, bronchoconstriction in guinea-pig) and plasma extravasation in rats. Nolpitantium was found to be effective in the modulation of the inflammatory response and airway remodeling in mice. Nolpitantium is reported to cause antagonism of the SP-induced relaxations of human isolated intralobar pulmonary arterial rings. Nolpitantium also blocked the activation of rat thalamic neurons after nociceptive stimulation. Nolpitantium has been shown to reduce the severity of inflammation in trinitrobenzene sulfonic acid-induced colitis in the rat colon. Nolpitantium inhibited mustard oil-induced plasma protein extravasations in the dorsal skin of the rat hind paw. Nolpitantium had been in some phase II clinical trials but further studies were discontinued.

Orvepitant is a novel generation brain penetrant, selective and potent, small molecule NK-1 receptor antagonist. Orvepitant’s (GW823296) mode of action and developability characteristics made it a suitable development candidate for the treatment of common anxiety disorders, posttraumatic stress disorder and major depressive disorder. It’s in phase II clinical trials as an effective inhibitor of itch-associated response.

Tradipitant is a neurokinin 1 receptor antagonist. The dose of 50 mg of tradipitant given orally for 4 weeks was not superior to placebo in reducing itch intensity in patients with atopic dermatitis. However, in a subsequent study, in which a higher dose (85 mg) was administered for 8 weeks, significant antipruritic effect compared with placebo was recorded. Tradipitant is in phase III clinical trial for the treatment of atopic dermatitis and gastroparesis. Vanda Pharmaceuticals plans a phase III trial in Motion Sickness in 2019.

Talnetant (SB-223412) is a selective, orally active neurokinin 3 receptor antagonist and is under development for the potential treatment of several disorders, including irritable bowel syndrome, schizophrenia, chronic obstructive pulmonary disease, cough, overactive bladder and urinary incontinence. The most common adverse effects were headache, fatigue, and nausea.

Befetupitant (Ro67-5930) is a high-affinity, competitive, tachykinin 1 receptor (NK1R) antagonist that was initially invented by Hoffmann-La Roche as a potential antiemetic drug. These studies were discontinued, because of the clinical trials with the more suitable drug, netupitant. Befetupitant was also investigated for topical application to reduced corneal neovascularization in the alkali burn model. However, the drug was toxic and was not tested in the suture model.