Dinaline represents a group of pharmacologically active lipophilic substances with a relatively simple structure derived from N-acyl-o-phenylenediamine. It has been found to exhibit high antineoplastic activity in a series of slowly growing tumors such as chemically induced rat mammary and colorectal carcinomas, osteosarcoma C22LR and Brown Norway myeloid leukemia. The drug was inactive against many of the typically hypersensitive signal tumors, i.e. mouse leukemias P388 and L1210, sarcoma 180 and Yoshida sarcoma. Colon carcinoma cells exposed to dinaline demonstrate distinct but reversible changes in amino acid transport, protein metabolism, DNA synthesis and cell proliferation.

Ciluprevir (BILN-2061) is a selective inhibitor of the HCV NS3 serine protease, which was developed by Boehringer Ingelheim for the treatment of hepatitis C infection. The drug was discontinued in phase II due to adverse events such as cardiac toxicity (demonstrated in animals). In the cell-based replicon assay, ciluprevir inhibited HCV RNA replication at low nanomolar levels. It had inhibitory rate constant (Ki) values of 0.3 and 0.66 nM for the NS3 proteases of HCV genotypes 1a and -1b, respectively.

Talotrexin (also known as PT-523) was developed as a nonpolyglutamatable antifolate drug for the treatment of various types of tumors. It is known that antifolates are a class of cytotoxic or antineoplastic agents, which inhibit or prevent the maturation and proliferation of malignant cells. Talotrexin was studied in clinical trials for the treatment of brain and central nervous system tumors, leukemia, lymphoma, unspecified childhood solid tumor. However, this study was withdrawn because of toxicity. In addition, was studied in phase I/II multicenter clinical trial in patients with non-small-cell Lung carcinoma, this study was also withdrawn. The withdrawal was related to incidences of dose-limiting mucositis and myelosuppression. However, on May 22, 2006, was announced that the U.S. Food and Drug Administration has granted orphan drug designation for talotrexin in patients with acute lymphoblastic leukemia (ALL).

Sulfonamide derivative Disulfamide was developed as diuretic agent.

Quazinone (also known as Ro 13-6438 ) is a cardiotonic and vasodilator drug which was developed and marketed in the 1980s for the treatment of heart disease. The positive inotropic response to Quazinone of the isolated guinea pig papillary muscle was accompanied by inhibition of myocardial phosphodiesterase (PDE) activity and elevation of intracellular cyclic AMP (cAMP) levels Quazinone had no effect on Na+, K+-stimulated or Ca2+-stimulated ATPase activity and did not influence the rate of calcium uptake in cardiac membrane vesicles. Quazinone caused a concentration-dependent increase in the upstroke velocity, overshoot, and duration of slow action potentials evoked in partially depolarized papillary muscles. Pretreatment of guinea pigs with reserpine did not prevent the effects of Quazinone on slow action potentials but slightly decreased its positive inotropic activity. In clinical trials, Quazinone induces dose-dependent hemodynamic changes, an increase in cardiac index combined with decreases in pulmonary capillary wedge pressure and systemic and pulmonary arterial pressures.

Perifosine is an orally active alkyl-phosphocholine compound with potential antineoplastic activity. Perifosine is an Akt inhibitor, which targets the pleckstrin homology domain of Akt, thereby preventing its translocation to the plasma membrane. Perifosine exerts Akt-dependent and Akt-independent effects, and although many preclinical studies have documented Akt inhibition by perifosine, clinical validation of these findings is lacking. Perifosine is in phase II and III clinical trials for the treatment of neuroblastoma, glioblastoma multiforme and other solid tumors.

Gisadenafil is a phosphodiesterase V inhibitor in clinical development at Pfizer. It had been in phase II clinical trials for the treatment of Benign prostatic hyperplasia; Chronic obstructive pulmonary disease; Erectile dysfunction; Overactive bladder. Treatment-emergent adverse events were: headache, myalgia, dyspepsia, back pain.

Talabostat is a prolineboronate ester derivative patented by Boehringer Ingelheim Pharmaceuticals, Inc. as an antineoplastic agent. Talabostat inhibits dipeptidyl peptidases, such as fibroblast activation protein (FAP), resulting in the stimulation of cytokine and chemokine production and specific T-cell immunity and T-cell dependent activity. Talabostat has been shown to cause caspase-1 activation and IL-1β induction in macrophages, which in turn causes upregulation of the cytokines and chemokines that characterize the responses to talabostat, both in vitro and in tumor-bearing mice. Talabostat may also stimulate the production of colony stimulating factors, such as granulocyte colony stimulating factor (G-CSF), resulting in the stimulation of hematopoiesis. In clinical trials, the combination of talabostat and cisplatin was well tolerated compared to historical data using cisplatin alone. The most frequent adverse events were nausea, vomiting, fatigue, anemia, edema, and constipation. Unfortunately was no evidence that Talabostat enhanced the clinical activity of other anticancer drugs and further development was discontinued.

Millennium Pharmaceuticals Inc's tandutinib (MLN-518), a piperazinyl derivative of quinazoline, is an orally active inhibitor of FLT3 kinase and family members PDGFR beta and c-Kit. Tandutinib inhibited FLT3 phosphorylation, downstream signaling and malignant growth in vitro and in animal models. The drug exhibited limited activity as a single agent in phase I and II clinical trials in patients with AML and myelodysplastic syndrome, but displayed promising antileukemic activity (90% complete remissions) in a phase I/II trial in patients with newly diagnosed AML when administered in combination with cytarabine and daunorubicin. Phase II clinical trials for tandutinib in patients with Glioblastoma have being discontinued. The use of tandutinib to treat AML has been granted fast-track status by the U.S. Food and Drug Administration. Phase II trials were underway., but later withwrawn.