Bevenopran (also known as CB-5945), a peripherally acting mu-opioid receptor antagonist that was studied for the treatment of opioid-induced constipation. Due to difficulties with enrollment, phase III of clinical trials were terminated early.

BX 471 is an oral nonpeptide chemokine receptor1 (CCR1) antagonist that was under clinical development with Bayer Healthcare Pharmaceuticals (formerly Bayer Schering Pharma AG and Berlex) for the treatment of various inflammation-related disorders, including endometriosis. The CCR1 antagonist was also thought to have potential application in diagnostic imaging, particularly as an imaging biomarker for the diagnosis of Alzheimer's disease. Berlex initiated the development of the radiolabelled small molecule CCR1 antagonist, BX 471, for a specific diagnostic test for both early detection and for tracking disease progression following the discovery that the CCR1 protein was found in the brains of patients with Alzheimer's disease, and that increased levels of this protein were correlated with advancement of the disease. However, development of the agent for diagnostic imaging appears to have been discontinued. BX 471 was also in development for the treatment of autoimmune diseases, including multiple sclerosis and psoriasis; however, development in these indications, as well as multiple myeloma and endometriosis, also appears to have been discontinued. A phase II study of BX 471 in endometriosis had been completed.

Rislenemdaz, also known as MK-0657 or CERC‐30, is an orally active, selective NMDA receptor subunit 2B (NR2B) antagonist which was a study for the treatment of Parkinson's disease and major depressive disorder (MDD). The data from the phase I clinical trials have shown that drug was not effective in improving motor symptoms in patients with Parkinson disease. In case of using this drug to treat MDD, in spite of the Missing Primary Endpoint in phase II clinical trials, it was shown, that MK-0657 had possessed a potential clinical meaningfulness, that is why it was suggested to continue studying it for MDD patients.

AstraZeneca was developing AZD-2066, a metabotropic glutamate receptor 5 (mGLUR5) antagonist, for the oral treatment of pain indications (e.g. chronic neuropathic pain and painful diabetic neuropathies), depressive disorders and gastro-oesophageal reflux disease. AZD-2066 had been in phase II clinical trials by AstraZeneca for the treatment of diabetic neuropathic pain and phase I for the treatment of gastrooesophageal reflux disease (GERD). However, this reasearch had being discontinued.

Asapiprant, also known as S-555739, a selective Prostaglandin D2 receptor 1 antagonist, participated in phase III of clinical trials in Japan and in phase II of trials in the USA for patients with Allergic rhinitis.

Pavinetant, also known as MLE-4901, AZD-4901, AZD-2624, is a small molecule, orally active, selective neurokinin-3 (NK3) receptor antagonist developed for schizophrenia, hot flashes, and Polycystic ovary syndrome. The development for schizophrenia was discontinued due to lack of effectiveness. Phase II trials for polycystic ovary syndrome and for hot flashes showed the clinical risks exceeded benefits, in addition, abnormal liver function was observed, and that is why these studies were also discontinued.

Pfizer was developing PF-4455242, a selective, short-acting (non-"inactivating") antagonist of the κ-opioid receptor. PF-4455242 was pursued in phase I clinical trial for the treatment of the bipolar disorder and was also investigated as a treatment for depression and substance abuse. In September 2010 Pfizer discontinued the development of the compound.

Golvatinib is a highly potent, small-molecule, ATP-competitive inhibitor of c-Met and multiple members of the Eph receptor family plus c-Kit and Ron. Eisai was developing an oral formulation of golvatinib, which acts as both a c-Met inhibitor and a vascular endothelial growth factor receptor 2 antagonist with potential antineoplastic activity. Golvatinib binds to and inhibits the activities of both c-Met and VEGFR-2, which may inhibit tumor cell growth and survival of tumor cells that overexpress these receptor tyrosine kinases. c-Met and VEGFR-2 are upregulated in a variety of various tumor cell types and play important roles in tumor cell growth, migration and angiogenesis. Clinical trials involving several forms of cancer are currently underway.

Navarixin (SCH 527123) is an oral antagonist of CXC receptors 1 and 2. The drug is currently under Phase II trial for the treatment of psoriasis, COPD and asthma.