Combretastatin A4 is a vascular disrupting agent (VDA) that targets tumor vasculature to inhibit angiogenesis. Combretastatin A4 is a tubulin-binding agent that binds at or near the colchicine binding site of β-tubulin and inhibits tubulin assembly. This tubulin-binding agent was originally isolated from an African shrub, Combretum caffrum. Combretastatin A4 is cytotoxic to umbilical-vein endothelial cells (HUVECs) and to a range of cells derived from primary tumors and these cytotoxicity profiles have been used to assess several novel analogs of the drug for future development. Combretastatin A4 has antitumor activity by inhibiting AKT function. The inhibited AKT activation causes decreased cell proliferation, cell cycle arrest, and reduced in vitro migration/invasiveness and in vivo metastatic ability. Several studies in mice have shown that a single administration of combretastatin A4 (100 mg/kg) does not significantly affect primary tumor growth. However, repeated administration (12.5 – 25.0mg/kg twice daily) for periods of 10 – 20 days resulted in approximately 50% retardation of growth of ectopic Lewis lung carcinoma and substantial growth delay of T138 spontaneous murine breast tumors. In clinical studies, Combretastatin A4 has been well tolerated in patients at doses up to 56 mg/m2, following a protocol of five daily 10-minute intravenous infusions every 21 days. The disodium combretastatin A4 phosphate prodrug is currently undergoing clinical trials in the UK and USA.

Acolbifene, the active metabolite of EM-800, was identified as a pure antagonist that acts on both activation domains of the ERs. It is in Phase III clinical trials for the prevention of breast cancer and vasomotor symptoms (Hot flush) in postmenopausal women. Most commonly reported adverse events included irregular menses, leg/muscle cramps, diarrhea, and hot flashes. No serious adverse events were reported.

The novel compounds clamikalant (HMR 1883) or its sodium salt HMR 1098) have been shown to block selectively Kir6.2/SUR1-composed K(ATP) channels. Clamikalant is under development by Aventis Pharma (formerly Hoechst Marion Roussel) for the potential treatment of heart arrest and ventricular arrhythmias. Nevertheless, clamikalant and its sodium salt did not pass the clinical trials

Alvocidib (also known as Flavopiridol or HMR-1275) is a flavonoid alkaloid CDK9 kinase inhibitor under clinical development for the treatment of acute myeloid leukemia, by Tolero Pharmaceuticals, Inc. As a broad spectrum CDK inhibitor, Alvocidib can inhibit cell cycle progression in either G1 or G2 and induces G1 arrest in either MCF-7 or MDA-MB-468 cells by inhibition of the CDK4 or CDK2 kinase activity. Alvocidib exhibits potent cytotoxicity against a wide variety of tumor cell lines (LNCAP, HCT116, A2780, K562, PC3, and Mia PaCa-2) with IC50 values ranging from 16 nM for LNCAP to 130 nM for K562. Administration of Alvocidib at 7.5 mg/kg for 7 days displays slight antitumor activity against P388 murine leukemia, and active against the human A2780 ovarian carcinoma implanted sc in nude mice). Alvocidib treatment at 1-2.5 mg/kg for 10 days significantly suppresses collagen-induced arthritis in mice in a dose-dependent manner, by inhibiting synovial hyperplasia and joint destruction, whereas serum concentrations of anti-collagen type II (CII) Abs and proliferative responses to CII are maintained. Tolero Pharmaceuticals Inc. announced that the FDA has granted orphan drug designation for Alvocidib, its cyclin-dependent kinase small molecule inhibitor, for the treatment of patients with acute myeloid leukemia.

Acolbifene, the active metabolite of EM-800, was identified as a pure antagonist that acts on both activation domains of the ERs. It is in Phase III clinical trials for the prevention of breast cancer and vasomotor symptoms (Hot flush) in postmenopausal women. Most commonly reported adverse events included irregular menses, leg/muscle cramps, diarrhea, and hot flashes. No serious adverse events were reported.

GV 150526A (gavestinel) is an investigational drug for a neuroprotective therapy of acute ischemic stroke within 6 hours of symptom onset. It is a potent and selective non-competitive antagonist at the glycine site of the N-methyl-D-aspartate receptor (NMDA) which reduces infarct volume in experimental stroke models. Gavestinel acts at the strychnine-insensitive glycine binding site of the NMDA receptor-channel complex with nanomolar affinity (pKi = 8.5), coupled with high glutamate receptor selectivity. Gavestinel displays higher than 1000-fold selectivity over NMDA, AMPA and kainate binding sites and is orally bioavailable and active in vivo. GV 150526A inhibited convulsions induced by NMDA in mice, when administered by both IV and po routes (ED50 = 0.06 and 6 mg/kg, respectively). The safety and efficacy of GV150526 were studied in two phase III randomized placebo-controlled clinical trials of acute ischemic stroke patients within 6 h from onset [The Glycine Antagonist in Neuroprotection (GAIN) International and GAIN Americas Trials] sponsored by GlaxoSmithKline. The results of these trials suggested that gavestinel was not of substantial benefit or harm to patients with primary intracerebral hemorrhage.

P-Cresol is an end product of protein breakdown and also it is a fermentation metabolite of tyrosine. The mechanisms underlying colonic carbohydrate and protein fermentation, responsible for the generation of p-cresol, are only partially understood. After absorption, the majority of p-cresol is conjugated to form p-cresyl sulphate. There is clear evidence, both in vitro and in vivo, that accumulation of conjugated fermentation metabolites is correlated with clinical important endpoints. In renal failure, the colonic generation rate of p-cresol is markedly elevated. Free p-cresol is an independent predictor for mortality in hemodialysis patients. The accumulation of p-cresol increases the cardiovascular risk of chronic kidney disease (CKD) patients. It was shown, that p-cresol l triggered autophagic renal proximal tubular cells death via JNK-mediated p62 accumulation and then activated caspase 8-dependent cell death pathway. Thus p-cresol can be considered as one of the key events causing progression of CKD, which might affect drug disposition in CKD cases.

Lesinurad (brand name Zurampic) is a urate transporter inhibitor for treating hyperuricemia associated with gout in patients who have not achieved target serum uric acid levels with a xanthine oxidase inhibitor alone. In gout patients, Lesinurad lowered serum uric acid levels and increased renal clearance and fractional excretion of uric acid. Following single and multiple oral doses of Lesinurad to gout patients, dose-dependent decreases in serum uric acid levels and increases in urinary uric acid excretion were observed. Lesinurad reduces serum uric acid levels by inhibiting the function of transporter proteins involved in uric acid reabsorption in the kidney. Lesinurad inhibited the function of two apical transporters responsible for uric acid reabsorption, uric acid transporter 1 (URAT1) and organic anion transporter 4 (OAT4), with IC50 values of 7.3 and 3.7 µM, respectively. URAT1 is responsible for the majority of the reabsorption of filtered uric acid from the renal tubular lumen. OAT4 is a uric acid transporter associated with diuretic-induced hyperuricemia. Lesinurad does not interact with the uric acid reabsorption transporter SLC2A9 (Glut9), located on the basolateral membrane of the proximal tubule cell. Based on in vitro studies, lesinurad is an inhibitor of OATP1B1, OCT1, OAT1, and OAT3; however, lesinurad is not an in vivo inhibitor of these transporters. In vivo drug interaction studies indicate that lesinurad does not decrease the renal clearance of furosemide (substrate of OAT1/3), or affect the exposure of atorvastatin (substrate of OATP1B1) or metformin (substrate of OCT1). Based on in vitro studies, lesinurad has no relevant effect on P-glycoprotein.

Lesinurad (brand name Zurampic) is a urate transporter inhibitor for treating hyperuricemia associated with gout in patients who have not achieved target serum uric acid levels with a xanthine oxidase inhibitor alone. In gout patients, Lesinurad lowered serum uric acid levels and increased renal clearance and fractional excretion of uric acid. Following single and multiple oral doses of Lesinurad to gout patients, dose-dependent decreases in serum uric acid levels and increases in urinary uric acid excretion were observed. Lesinurad reduces serum uric acid levels by inhibiting the function of transporter proteins involved in uric acid reabsorption in the kidney. Lesinurad inhibited the function of two apical transporters responsible for uric acid reabsorption, uric acid transporter 1 (URAT1) and organic anion transporter 4 (OAT4), with IC50 values of 7.3 and 3.7 µM, respectively. URAT1 is responsible for the majority of the reabsorption of filtered uric acid from the renal tubular lumen. OAT4 is a uric acid transporter associated with diuretic-induced hyperuricemia. Lesinurad does not interact with the uric acid reabsorption transporter SLC2A9 (Glut9), located on the basolateral membrane of the proximal tubule cell. Based on in vitro studies, lesinurad is an inhibitor of OATP1B1, OCT1, OAT1, and OAT3; however, lesinurad is not an in vivo inhibitor of these transporters. In vivo drug interaction studies indicate that lesinurad does not decrease the renal clearance of furosemide (substrate of OAT1/3), or affect the exposure of atorvastatin (substrate of OATP1B1) or metformin (substrate of OCT1). Based on in vitro studies, lesinurad has no relevant effect on P-glycoprotein.

Lesinurad (brand name Zurampic) is a urate transporter inhibitor for treating hyperuricemia associated with gout in patients who have not achieved target serum uric acid levels with a xanthine oxidase inhibitor alone. In gout patients, Lesinurad lowered serum uric acid levels and increased renal clearance and fractional excretion of uric acid. Following single and multiple oral doses of Lesinurad to gout patients, dose-dependent decreases in serum uric acid levels and increases in urinary uric acid excretion were observed. Lesinurad reduces serum uric acid levels by inhibiting the function of transporter proteins involved in uric acid reabsorption in the kidney. Lesinurad inhibited the function of two apical transporters responsible for uric acid reabsorption, uric acid transporter 1 (URAT1) and organic anion transporter 4 (OAT4), with IC50 values of 7.3 and 3.7 µM, respectively. URAT1 is responsible for the majority of the reabsorption of filtered uric acid from the renal tubular lumen. OAT4 is a uric acid transporter associated with diuretic-induced hyperuricemia. Lesinurad does not interact with the uric acid reabsorption transporter SLC2A9 (Glut9), located on the basolateral membrane of the proximal tubule cell. Based on in vitro studies, lesinurad is an inhibitor of OATP1B1, OCT1, OAT1, and OAT3; however, lesinurad is not an in vivo inhibitor of these transporters. In vivo drug interaction studies indicate that lesinurad does not decrease the renal clearance of furosemide (substrate of OAT1/3), or affect the exposure of atorvastatin (substrate of OATP1B1) or metformin (substrate of OCT1). Based on in vitro studies, lesinurad has no relevant effect on P-glycoprotein.