Patient safety clinical studies

A review of the use of zanamivir in 6000 patients in clinical studies has confirmed its favorable safety profile (10). To date there is still an optimistic impression that the adverse reactions pattern is no different from that of placebo and that interactions are also unlikely, since it does not inhibit cjdochrome P450 (11). 

Phase II. Initial clinical studies for therapeutic safety and efficacy are performed in volunteer patients who are suffering from the disease for which the dmg has therapeutic promise. Recognition of toxic symptoms and side effects are vital at this point because these may occur here, even when not observed in animal studies or in Phase I. 

Clinical studies with Norplant attest to its high contraceptive efficacy and safety. The main reason patients request the removal of Norplant is unpredictable vaginal bleeding episodes followed by amenorrhea. The bleeding problem is an unavoidable sequela of progestogen-only contraception. 

Rimonabant (382) was also included in a clinical study to assess the safety and efficacy of four novel compounds for the treatment of schizophrenia and psychoaffective disorder [378]. The other compounds included in the trial were a neurokinin NK3 antagonist, a serotonin 2A/2C antagonist and a neurotensin NTSl antagonist. Halopeiidol and placebo groups were used as controls in the study. Sixty-nine patients received (382) (20 mg once per day), which failed to demonstrate efficacy in this trial. The reasons for the lack of efficacy may be due to inadequate dosing or an indication that CBi antagonism is not appropriate in the treatment of this condition. 

FIGURE 69-3. Treatment algorithm3 for acute bacterial rhinosinusitis in patients with mild disease without recent antibiotic exposure.31 aAntibiotics are listed in order of predicted efficacy based on predicted clinical and bacteriologic efficacy rates, clinical studies, safety, and tolerability. Doses can be found in Table 69-4. 6Cephalosporins should be considered for patients with non-type I hypersensitivity to penicillins they are more likely to be effective than the alternative agents. cHigh doses (90 mg/kg per day) are recommended for most children, especially those with day-care contacts or frequent infections. 

The study termination form data may be used for efficacy or safety analysis purposes. With regard to safety, if patients discontinue a study medication earlier than patients on standard therapy or placebo, then that is important to know. For efficacy analyses, patients who withdraw due to a lack of efficacy or adverse event may be precluded from being considered a treatment responder or success. Also, often the study termination date is used as a censor date in time-to-event analyses for therapy efficacy. Study termination forms play a key role in patient disposition summaries found at the start of a clinical study report. From a CDISC perspective, the study termination form is a finding. 

To determine whether human testing for a new drug or new drug product is reasonable, it is first necessary to conduct preclinical studies and to submit the IND. The necessary information needed to prepare the IND is outlined in Table 1. The IND is to contain information on appropriate prior animal studies for safety evaluation, any available clinical data, adequate drug identification and manufacturing instructions, and a detailed outline of the proposed clinical study, routs of administration, approximate number of patients to be used, and an estimate of the length of treatment and an environmental impact statement. 

The product was evaluated in two multicentre clinical studies that established safety and efficacy. The first (the PRISMS study) was a randomized, double blind placebo-controlled study involving 187 patients. The primary efficacy end-point was the number of clinical relapses recorded. The mean number of relapses over 2 years for the placebo group patients was 2.56, whereas that of the Rebif-treated group was 1.73, a relative reduction of 32 per cent. Rebif treatment also provided positive relative outcomes for several secondary end-points, including the proportion of patients with sustained disability progression. 

Pre-approval safety and efficacy clinical studies involved product administration to 2500 adults with either type-1 or -2 diabetes. The primary efficacy parameter measured was glycaemic control (as measured by the reduction from baseline in haemoglobin Ale). Hypoglycaemia was the most commonly reported adverse effect. Trials also showed a greater decline in pulmonary function in the Exubera group, and product should not be administered to patients with underlying lung disease, or to smokers. Exubera was developed by Nektar Inc. and is marketed under licence by Pfizer. 

Trioxifene is an older SERM with low estrogenic properties and a higher affinity for ER than tamoxifen. It has shown an unfavorable safety profile in clinical studies of women with breast cancer (leukopenia in 41% of patients, nausea in 31%) (Witte et al. 1986), which is why, in addition to its response rates being no better than in tamoxifen (Lee et al. 1986), its clinical development has been cancelled. 

Fibrates are being combined with statins to expand their potential in the dyslipidemia market. A recent clinical study examined the effects of rosuvastatin (10) and fenofibrate as mono and combination therapy in hyperlipidemic diabetic patients [43]. In late 2006, large scale Phase III clinical trials of rosuvastatin in combination with a next-generation fibrate, ABT 335, were initiated for evaluation of safety and efficacy in patients with mixed dyslipidemia. 

Phase IV. Studies or trials conducted after a medicine is marketed to provide additional details about the medicine s efficacy or safety profile. Different formulations, dosages, durations of treatment, medicine interactions, and other medicine comparisons may be evaluated. New age groups, races, and other types of patients can be studied. Detection and definition of previously unknown or inadequately quantified adverse reactions and related risk factors are an important aspect of many Phase IV studies. If a marketed medicine is to be evaluated for another (i.e., new) indication, then those clinical trials are considered Phase II clinical trials. The term postmarketing surveillance is frequently used to describe those clinical studies in Phase IV (i.e., the period following marketing) that are primarily observational or nonexperimental in nature, to distinguish them from well-controlled Phase IV clinical trials or marketing studies. 

Phase I studies evaluate the pharmacokinetics and safety of the drug in a small number (tens) of healthy volunteers. Phase I studies are sometimes conducted in a small patient population (Proof of Concept studies) with a specific objective such as the validation of the relevance of preclinical models in man. The purpose of these studies may be the rapid elimination of potential failures from the pipeline, definition of biological markers for efficacy or toxicity, or demonstration of early evidence of efficacy. These studies have a potential go/no-go decision criteria such as safety, tolerability, bioavailability/PK, pharmacodynamics, and efficacy. Dosage forms used in Phase I or Proof of Concept studies must be developed with the objectives of the clinical study in mind. 

Phase II studies encompass a detailed assessment of the compound s safety and efficacy in a larger patient population (a few-to-several hundreds of patients). It is important that any formulation selected for these studies must be based on sound biopharmaceutical and pharmaceutical technology principles. Phase III clinical studies, also referred to as pivotal studies, involve several thousands of patients in multiple clinical centers, which are often in multiple countries. The aim of these studies is to demonstrate long-term efficacy and safety of the drug. Since these studies are vital in the approval of the drug, the dosage form plays a very critical role. 

In this section, a brief summary of the nature, frequency, and consequences of adverse drug reactions (ADRs) in two clinical situations is presented. There are ADRs experienced by healthy volunteers and patients participating in clinical studies with potential new medicines and those experienced by patients who are prescribed licensed medicines. A review of these two situations points to areas of success with the current practices for non-clinical safety pharmacology testing but also identifies some areas where further research might lead to new or better safety pharmacology tests. Prior to reviewing the literature, some... 

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