Clinical trials placebos

Acetyl-i-carnitine (4) is marketed in Italy for dementia as of this writing it is also in Phase III clinical trials in the United States and Europe. In a double-blind, placebo-controUed clinical trial over a one-year period involving 130 patients with clinically diagnosed AD, a slower rate of deterioration in 13 of the 14 outcome measures was observed in the dmg-treated group (28). Earfler smaller scale pilot studies in demented patients had also shown some improvement of various behavioral and cognitive functions (29). 

Aniracetam (6), launched in 1993 in both Japan and Italy for the treatment of cognition disorders, is in Phase II trials in the United States as of this writing. In clinical studies it has been shown to cause some improvement in elderly patients with mild to moderate mental deterioration (63), and in geriatric patients with cerebral insufficiency (64). In a multicenter double-blind placebo-controUed trial involving 109 patients with probable AD, positive effects were observed in 36% of patients after six months of treatment (65), a result repeated in a separate study of 115 patients (66). A review of the biological and pharmacokinetic properties, and clinical results of aniracetam treatment in cognitively impaired individuals is available (49). 

Several clinical trials have been conducted with streptokinase adrninistered either intravenously or by direct infusion into a catheterized coronary artery. The results from 33 randomized trials conducted between 1959 and 1984 have been examined (75), and show a significant decrease in mortaUty rate (15.4%) in enzyme-treated patients vs matched controls (19.2%). These results correlate well with an ItaUan study encompassing 11,806 patients (76), in which the overall reduction in mortaUty was 19% in the streptokinase-treated group, ie, 1.5 million units adrninistered intravenously, compared with placebo-treated controls. The trial also shows that a delay in the initiation of treatment over six hours after the onset of symptoms nullifies any benefit from this type of thrombolytic therapy. Conversely, patients treated within one hour from the onset of symptoms had a remarkable decrease in mortaUty (47%). The benefits of streptokinase therapy, especially in the latter group of patients, was stiU evident in a one-year foUow-up (77). In addition to reducing mortahty rate, there was an improvement in left ventricular function and a reduction in the size of infarction. Thus early treatment with streptokinase is essential. 

However, already in an early clinical trial, rofecoxib was found to produce four times the number of myocardial infarctions than its comparator drug, naproxen. A subsequent trial of rofecoxib compared to placebo in colorectal cancer prevention demonstrated, after 18 months of study, that a greater number of myocardial infarctions occulted in the rofecoxib group. In 2004 the manufacturers of rofecoxib withdrew the diug from the market. A similar study of celecoxib compared to placebo in cancer prevention, showed that celecoxib also increased the risk of cardiovascular embolisms [3]. 

The clinical trial that resulted in FDA approval of bevacizumab (February 2004) was a randomized, double-blind, phase III study in which bevacizumab was administered in combination with bolus-IFL (irinotecan, 5FU, leucovorin) chemotherapy as first-line therapy for previously untreated metastatic colorectal cancer [3]. Median survival was increased from 15.6 months in the bolus-IFL + placebo arm to 20.3 months in the bolus-IFL + bevacizumab arm. 

It has been proposed that the development of the complications of diabetes mellitus may be linked to oxidative stress and therefore might be attenuated by antioxidants such as vitamin E. Furthermore, it is discussed that glucose-induced vascular dysfunction in diabetes can be reduced by vitamin E treatment due to the inactivation of PKC. Cardiovascular complications are among the leading causes of death in diabetics. In addition, a postulated protective effect of vitamin E (antioxidants) on fasting plasma glucose in type 2 diabetic patients is also mentioned but could not be confirmed in a recently published triple-blind, placebo-controlled clinical trial [3]. To our knowledge, up to now no clinical intervention trials have tested directly whether vitamin E can ameliorate the complication of diabetes. 

Clinical trials should be designed so as to mirtimise potential sources of bias. It is known that patients can demonstrate a positive response to treatments that they believe will benefit them, even if no pharmaceutical agent has been admrrtistered (the placebo effect ). Similarly, investigators may be biased in their observations by an expectation of particular results. To avoid such bias, blinded trial designs are used. 

The manufacture of all investigational medicinal products (including placebo) that are intended for a clinical trial must be authorised and conducted according to Good Manufacturing Practice (GMP). This should be supervised and certified by a Qualified Person . An import authorisation is required for any product from outside the EU, which should also be manufactured to GMP standards. (See Ghapters 11 and 12 for information on GMP, manufacturing authorisations and Qualified Persons.)... 

Kranzler HR, Wesson DR, Billot L Naltrexone depot for treatment of alcohol dependence a multicenter, randomized, placebo-controlled clinical trial. Alcohol Clin... 

Nestler EJ, Hyman SE, Malenka RC Molecular Neuropharmacology A Foundation for Clinical Neuroscience. New York, McGraw Hill, 2001 Novick DM, Pascarelli EE, Joseph H, et al Methadone maintenance patients in general medical practice a preliminary report. JAMA 259 3299—3302, 1988 Nunes EV, Quitkin EM, Donovan SJ, et al. Imipramine treatment of opiate-dependent patients with depressive disorders a placebo-controlled trial. Arch Gen Psychiatry 55 153-160, 1998... 

Kranzler HR, Bauer LO, Hersh D, et al Carbamazepine treatment of cocaine dependence a placebo-controlled trial. Drug Alcohol Depend 38 203-211, 1995 Levin FR, Lehman AF Meta-analysis of desipramine an adjunct in the treatment of cocaine addiction. J Clin Pharmacol 11 374-378, 1991 Lima MS, Reisser AA, Soares BG, et al Antidepressants for cocaine dependence. Cochrane Database Syst Rev 4 CD002950, 2001 Ling W, Shoptaw S, Majewska D Baclofen as a cocaine anti-craving medication a preliminary clinical study 0etter). Neuropsychopharmacology 18 403 04, 1998... 

Highly selective COX-2 inhibitors - coxibs (rofecoxib, celecoxib, or less popular - valdecoxib, etoricoxib parecoxiband lumiracoxib) - were found to be well tolerated in a series of placebo-controlled clinical trials [8]. However, rofecoxib and valdecoxib have been withdrawn from the market because of an increased incidence... 

Tollefson GD, Sanger TM (1997). Negative symptoms a path analytic approach to a double blind, placebo controlled clinical trial with olanzapine. Am J Psychiatry 154,... 

Yamaguchi T, Sano K, Takakura K, Saito I, Shinohara Y, Asano T, Yasuhara H. Ebselen in acute ischemic stroke a placebo-controlled, double-blind clinical trial. Ebselen study group. Stroke 1998 29 12-17. 

Anticoagulation in Stroke Due to LAA Disease Few clinical trials have been performed in this population. In the TOAST trial, a secondary analysis in patients with stroke due to LAA found favorable outcomes at 7 days in 54% of danaparoid-treated patients, compared to 38% of the placebo-treated group (p = 0.02). At 3 months, 68% of patients in the danaparoid group compared to 53% of those in the placebo group had favorable outcomes (p = 0.02). 

The mean dietary intake of soy isoflavones in Asian populations consuming soy-based diets ranges from 20-40 mg isoflavones/day, with upper percentile consumer intakes of 70 mg/day (corresponding to around 1 mg/kg body weight). In the six month intervention studies in Western postmenopausal women, the effective dose for improved BMD was around 80-90 mg/day, while in the one year, randomized, double-blind, placebo controlled clinical trial, the effective dose was 54 mg/day. Overall, the dietary recommendation is to consume 50 mg isoflavones/day in combination with standard nutritional requirements for calcium and vitamin D. 

For any intervention intended to impact favorably upon human health, it is important to evaluate its safety and efficacy in order to demonstrate that it does not cause harm and it does provide the expected benefit. The gold standard method for evaluating any intervention, whether it be a botanical product, dietary supplement, drug, medical device or medical procedure, is the randomized, clinical trial (RCT). A clinical trial is a type of experiment conducted in human subjects where the effects of at least two interventions are compared. Often, the clinical trial takes the form of an active treatment compared to an inactive control or placebo. 

There are two main types of clinical trial design, parallel and cross-over. In a parallel study, subjects are assigned to one of two or more treatments, e.g. active and placebo, and proceed through the trial concurrently. In a cross-over design, subjects act as their own controls, undergoing two or more treatments in sequence (see Fig. 12.1). 

PORKKALA-SARATAHO E K, NYYSSONEN K M, KAIKKONEN J E, POULSEN H E, HAYN E M, SALONEN R M, SALONEN J T (1998) A randomized, single-blind, placebo controlled trial of the effects of 200 mg a-tocopherol on the oxidation resistance of atherogenic hpoproteins, American Journal of Clinical Nutrition, 68, 1034-41. 

KLIPPEL K F, HiLTL D M, scHipp B (1997) A multicentric placebo controlled double-blind clinical trial of beta-sitosterol for the treatment of benign prostate hyperplacia. British J Urology, 80(3) 427-32. 

Clemens, J.A., Bulkley, G.B., Cameron, J.L., Milligan, F.L., Hutcheon, L., Horn, S.D. and MacGowan, S.W. (1991). Effect of xanthine oxidase inhibition with allopurinol on the incidence and severity of post-ERCP pancreatitis and hyper-amylasaemia in a prospective, randomized, double-blind, placebo-controlled clinical trial of 168 patients. Gastroenterology 100, A270. 

Nesiritide has been shown to improve symptoms of dyspnea and fatigue. In a randomized clinical trial, the safety and efficacy of adding nesiritide to standard care was compared to placebo and nitroglycerin.53 Nesiritide was found to significantly decrease PCWP more than nitroglycerin and placebo over 3 hours. Nesiritide improved patients self-reported... 

---