Hydroxindasol was studied as a psychotropic agent. Information about the current use of this drug is not available.

Forodesine hydrochloride is the salt of the synthetic high-affinity transition-state analog forodesine (BCX-1777, immucillin-H), a substrate designed to mimic the properties or the geometry of the transition state of reaction. It is an anticancer drug that has been developed for the treatment of different hematologic malignancies. In December 2006, orphan designation (EU/3/06/421) was granted by the European Commission to Napp Pharmaceuticals Research Limited, United Kingdom, for forodesine hydrochloride for the treatment of acute lymphoblastic leukemia. Forodesine hydrochloride has been evaluated in Phase I/Phase II clinical trials for several cancer types including chronic lymphocytic leukemia (CLL), B-Cell acute lymphoblastic leukemia and refractory cutaneous T-cell lymphoma (CTCL). Forodesine is a potent purine nucleoside phosphorylase (PNP) inhibitor that acts by elevating plasma 2'-deoxyguanosine (dGuo) and intracellular deoxyguanosine triphosphate, which in turn affects deoxynucleotide-triphosphate pools and induces cell death by apoptosis. Forodesine in the presence of dGuo inhibited the proliferation of CEM-SS (T-acute lymphoblastic leukemia) cells with an IC50 of 0.015 uM. This inhibition by forodesine and dGuo was accompanied by a 154-fold and 8-fold elevation of endogenous dGuo triphosphate (dGTP) and deoxyadenosine triphosphate (dATP) pools, respectively. Cytotoxic activity of forodesine in the presence of dGuo was selective to T lymphocytes. It is a 10- to 100-fold more potent inhibitor of human lymphocyte proliferation than other known PNP inhibitors such as PD141955 and BCX-34.8

Ancriviroc (SCH 351125) is a small-molecule antagonist of the human immunodeficiency virus type 1(HIV-1) coreceptor CCR5. It has in vitro activity against R5 viruses with 50% inhibitory concentrations ranging from 1.0 to 30.9 nM. Ancriviroc is an orally bioavailable small molecule inhibitor of HIV-1 entry via CCR5 coreceptor interaction. Ancriviroc has potent activity against RANTES binding (K(i) = 2 nM), possesses subnanomolar activity in blocking viral entry and has excellent antiviral potency versus a panel of primary HIV-1 viral isolates. Ancriviroc had been in phase I clinical trials by Schering-Plough (subsidiary of Merck Sharp & Dohme) for the treatment of HIV infection. However, this research has been discontinued.

Atiprosin (AY-28,228), an octahydro-pyrazino-pyrido-indole drug, possesses the alpha-adrenoceptor antagonist activity and exerts antihypertensive effects. Atiprosin has never been marketed

Atliprofen (previously known as IDPH 8261), a nonsteroidal anti-inflammatory cyclooxygenase inhibitor was developed as an anti-inflammatory drug. Low toxicity and high efficacy allowed making this compound a potentially useful therapeutic agent. IDPH 8261 participated in the clinical trial phase III in India for the treatment of rheumatic disorders However, information about the further development of the drug is not available.

Ataprost (also known as ONO-41483; OP-41483), an epoprostenol agonist, participated in phase II clinical trials in Japan for the treatment patients with heart failure and myocardial ischemia. However, these trials were discontinued.

Ataquimast, previously known as L0066, inhibits leukotriene release, TNFa and GM-CSF release but have no effect on IL-8 release. This drug participated in clinical trials to treat asthma, but these studies were discontinued.

Asimadoline is an orally active, highly selective kappa-opioid receptor agonist with approximately 500-fold greater affinity for human kappa-, as compared with either delta- or mu-opioid receptors. Due to its high selectivity for the kappa-opioid receptor, asimadoline does not produce mu-opioid like side effects. It is investigated for use/treatment in irritable bowel syndrome, pruritus, postoperative ileus. A drug interaction study investigating the coadministration of asimadoline with ketoconazole was performed in healthy volunteers - a two to three-fold increase in AUC and Cmax of asimadoline was observed with concomitant administration of ketoconazole. The most common adverse events are diarrhea, nausea, sinusitis, headache and fatigue.

Ascorbyl gamolenate, an aldehyde reductase inhibitor, participated in phase-I clinical trials for Diabetic neuropathies in the United Kingdom but these studies were discontinued.

Aclantate is a nonsteroidal anti-inflammatory drug.