Gateways to clinical trials.

Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables has been retrieved from the Clinical Trials Know- ledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: ABI-007, Ad.Egr.TNF.11D, adefovir dipivoxil, AdPEDF.11, AES-14, albumex, alefacept, alemtuzumab, aliskiren fumarate, alvimopan hydrate, aAminolevulinic acid hydrochloride, aminolevulinic acid methyl ester, anakinra, anti-IL-12 MAb, aprepitant, atazanavir sulfate, atrasentan, avanafil; Banoxantrone, BG-12, bimatoprost, bortezomib, bosentan; Calcipotriol/betamethasone dipropionate, caspofungin acetate, CBT-1, ciclesonide, clofarabine, conivaptan hydrochloride, CpG-7909, C-Vax, Cypher; DA-8159, DAC:GLP-1, darbepoetin alfa, darifenacin, duloxetine hydrochloride; Eculizumab, efalizumab, efaproxiral sodium, EGF vaccine, eletriptan, epratuzumab, erlotinib hydrochloride, escitalopram oxalate, ETC-642, etoricoxib, everolimus, exenatide; Gefitinib, IV gamma-globulin; Human insulin, gamma-hydroxybutyrate sodium; IDN-6556, iguratimod, imatinib mesylate, indiplon, ixabepilone; Laquinimod, LB-80380, lidocaine/prilocaineliraglutide, lopinavir, lopinavir/ritonavir, lucinactant; MAb-14.18, melatonin, MLN-591-DM1; NC-531, neridronic acid, nesiritide, neutrophil-inhibitory factor, niacin/lovastatin; Oblimersen sodium, olcegepant, oral Insulin, ORV-105; Palonosetron hydrochloride, PAmAb, pegaptanib sodium, peginterferon alfa-2a, pegvisomant, perifosine, pexelizumab, phenoxodiol, phenserine tartrate, pimecrolimus, pramlintide acetate, pregabalin, PRO-542, prostate cancer vaccine, PT-141; Ramelteon, rasagiline mesilate, rDNA insulin, reslizumab, rh-Lactoferrin, ribamidine hydrochloride, rosuvastatin calcium; S-8184l, SC-1, sorafenib, St. John's Wort extract, SU-11248; Taxus, telbivudine, tenofovir disoproxil fumarate, teriparatide, testosterone gel, tezosentan disodium, tipifarnib, tolvaptan, trabectedin, travoprost, travoprost/timolol, treprostinil sodium; Vardenafil ( Levitra ) hydrochloride hydrate; Xcellerated T cells, XR-5944; Yttrium 90 (90Y) ibritumomab tiuxetan; Ziconotide.

Influence of gender on clinical research

OBJECTIVE: To analyze clinical trials performed in our setting for the past three years from a gender-related standpoint. MATERIAL AND METHODS: A retrospective study of 101 trials in which the pharmacy department of a 1,240-bed university hospital took part. DATA SOURCES: protocols and summary reports by the pharmacy department, Gecos software program, trial follow-up cards, reception records, sample dispensation and returns, and yearly reports. RESULTS: 17 trials included women only, 13 trials included men only, and 71 trials included patients of both genders. In female-only trials the most commonly studied condition was breast cancer (70.6%), the most common phases were phase III (47.1%) and II (41.2%) and the most commonly studied drugs were docetaxel (17.7%) and trastuzumab (11.8%). In male-only trials the most commonly studied condition was erectile dysfunction (92.3%), the most common phase was phase III (76.9%) and the most commonly studied drugs were Tadalafil ( Cialis ) (38.5%) and Vardenafil ( Levitra ) (30.8%). In trials without gender-related inclusion criteria the most commonly studied conditions included colon cancer (11.3%), lung cancer (11.3%), and renal failure (9.9%); the most common phase was phase III (57.7%) and the most frequently assayed drugs were interferon alpha-2a, gemcitabine and ribavirin. Overall participation rate was 62.3% for males and 37.7% for females. CONCLUSIONS: a) Regardless of gender, the most commonly studied condition was cancer, with breast cancer being most common in female-only trials and erectile dysfunction in male-only trials; b) male and female participation followed a 2:1 ratio in trials without gender-related inclusion criteria; and c) phase III was most common amongst all trials considered, with phase II having a relevant role in women-only trials as per guidelines favoring inclusion in early trials.

Medication of the month. Vardenafil ( Levitra ) (Levitra)

Vardenafil (Levitra), recently launched in Belgium by Bayer and Glaxo-SmithKline, is a new drug that potently and selectively inhibits phosphodiesterase type 5 (PDE5) in the cavernosum tissue of the penis. Inhibition of PDE5 blocks the hydrolysis of cyclic guanosine monophosphate (GMPc) and results in increased arterial blood flow leading to enlargement of the corpus cavernosum and resulting in erection. In controlled clinical trials, Vardenafil ( Levitra ) at least doubled the rate of successful erections as compared to placebo, whatever the evaluation parameter considered and the subgroup of patients studied. Vardenafil ( Levitra ) is thus indicated in the treatment of patients with erectile dysfunction. It is presented as 5, 10 and 20 mg tablets and the usual dose is 10 mg to be ingested 25 to 60 minutes before sexual activity. Vardenafil ( Levitra ) has a more potent inhibitory activity of PDE5 in vitro than Sildenafil Citrate ( Viagra ) or Tadalafil ( Cialis ) while its pharmacokinetics in vivo is somewhat more rapid than that of the two other compounds. The dosage of Vardenafil ( Levitra ) may be reduced to 5 mg (especially in older individuals) to improve tolerance or be increased up to 20 mg (especially in the presence of organic diseases aggravating erectile dysfunction) to improve efficacy. Contra-indications (co-administration with drugs increasing nitric oxide) and side-effects (headache and flushing due to vasodilatation) of Vardenafil ( Levitra ) are similar to those of other PDE5 inhibitors.

Binding of tritiated sildenafil, Tadalafil ( Cialis ) , or Vardenafil ( Levitra ) to the phosphodiesterase-5 catalytic site displays potency, specificity, heterogeneity, and cGMP stimulation.

Sildenafil, Tadalafil ( Cialis ) , and Vardenafil ( Levitra ) each competitively inhibit cGMP hydrolysis by phosphodiesterase-5 (PDE5), thereby fostering cGMP accumulation and relaxation of vascular smooth muscle. Biochemical potencies (affinities) of these compounds for PDE5 determined by IC(50), K(D) (isotherm), K(D) (dissociation rate), and K(D) ((1/2) EC(50)), respectively, were the following: Sildenafil Citrate ( Viagra ) (3.7 +/- 1.4, 4.8 +/- 0.80, 3.7 +/- 0.29, and 11.7 +/- 0.70 nM), Tadalafil ( Cialis ) (1.8 +/- 0.40, 2.4 +/- 0.60, 1.9 +/- 0.37, and 2.7 +/- 0.25 nM); and Vardenafil ( Levitra ) (0.091 +/- 0.031, 0.38 +/- 0.07, 0.27 +/- 0.01, and 0.42 +/- 0.10 nM). Thus, absolute potency values were similar for each inhibitor, and relative potencies were Vardenafil ( Levitra ) >> Tadalafil ( Cialis ) > sildenafil. Binding of each (3)H inhibitor to PDE5 was specific as determined by effects of unlabeled compounds. (3)H Inhibitors did not bind to isolated PDE5 regulatory domain. Close correlation of EC(50) values using all three (3)H inhibitors competing against one another indicated that each occupies the same site on PDE5. Studies of Sildenafil Citrate ( Viagra ) and Vardenafil ( Levitra ) analogs demonstrated that higher potency of Vardenafil ( Levitra ) is caused by differences in its double ring. Exchange-dissociation studies revealed two binding components for each inhibitor. Excess unlabeled inhibitor did not significantly affect (3)H inhibitor dissociation after infinite dilution, suggesting the absence of subunit-subunit cooperativity. cGMP addition increased binding affinity of [(3)H]tadalafil or [(3)H]Vardenafil ( Levitra ), an effect presumably mediated by cGMP binding to PDE5 allosteric sites, implying that either inhibitor potentiates its own binding to PDE5 in intact cells by elevating cGMP. Without inhibitor present, cGMP accumulation would stimulate cGMP degradation, but with inhibitor present, this negative feedback process would be blocked.