The basics of preclinical drug development for neurodegenerative disease indications.

Preclinical development encompasses the activities that link drug discovery in the laboratory to initiation of human clinical trials. Preclinical studies can be designed to identify a lead candidate from several hits; develop the best procedure for new drug scale-up; select the best formulation; determine the route, frequency, and duration of exposure; and ultimately support the intended clinical trial design. The details of each preclinical development package can vary, but all have some common features. Rodent and nonrodent mammalian models are used to delineate the pharmacokinetic profile and general safety, as well as to identify toxicity patterns. One or more species may be used to determine the drug's mean residence time in the body, which depends on inherent absorption, distribution, metabolism, and excretion properties. For drugs intended to treat Alzheimer's disease or other brain-targeted diseases, the ability of a drug to cross the blood brain barrier may be a key issue. Toxicology and safety studies identify potential target organs for adverse effects and define the Therapeutic Index to set the initial starting doses in clinical trials. Pivotal preclinical safety studies generally require regulatory oversight as defined by US Food and Drug Administration (FDA) Good Laboratory Practices and international guidelines, including the International Conference on Harmonization. Concurrent preclinical development activities include developing the Clinical Plan and preparing the new drug product, including the associated documentation to meet stringent FDA Good Manufacturing Practices regulatory guidelines. A wide range of commercial and government contract options are available for investigators seeking to advance their candidate(s). Government programs such as the Small Business Innovative Research and Small Business Technology Transfer grants and the National Institutes of Health Rapid Access to Interventional Development Pilot Program provide funding and services to assist applicants in preparing the preclinical programs and documentation for their drugs. Increasingly, private foundations are also funding preclinical work. Close interaction with the FDA, including a meeting to prepare for submission of an Investigational New Drug application, is critical to ensure that the preclinical development package properly supports the planned phase I clinical trial.

Pharmacist detection of peripheral arterial disease through the use of a handheld Doppler.

STUDY OBJECTIVE: To evaluate the effectiveness of a program in which pharmacists screened at-risk patients for peripheral arterial disease using a handheld doppler device. DESIGN: Prospective study. SETTING: Primary care and consultative outpatient clinic. PATIENTS: Forty-one physician-referred patients older than 55 years who had no documented history of peripheral arterial disease. INTERVENTION: The pharmacists administered the San Diego Claudication Questionnaire and performed doppler examinations to calculate ankle-to-brachial indexes (ABIs). Patients with symptoms of claudication or with an ABI of 0.9 or less were considered to have possible peripheral arterial disease. Each diagnosis was confirmed by a physician. These patients were either referred for further evaluation, provided with immediate treatment, or told to continue their current drug regimen, if appropriate. MEASUREMENTS AND MAIN RESULTS: Eight (19.5%) of the 41 patients were diagnosed with peripheral arterial disease. Antiplatelet therapy was started in five patients, and one patient was referred to a vascular specialist. CONCLUSION: This pharmacist-initiated program effectively detected peripheral arterial disease in previously unscreened patients.

Colesevelam: potential uses for the newest bile resin.

Colesevelam is the newest bile resin with a unique chemical structure. It binds to bile acids with higher affinity than traditional bile acid sequestrants and has fewer gastrointestinal side effects and drug interactions. Colesevelam is safe and efficacious alone or in combination with HMG-CoA reductase inhibitors (statins) in reducing low-density lipoprotein cholesterol (LDL-C) levels. Despite this, the role of colesevelam in the treatment of hyperlipidemia remains limited, particularly in the face of new lipid lowering agents. As guidelines for cholesterol control become more stringent, the need to maximize therapeutic benefit through combination therapy will become increasingly more important. Colesevelam has a dose-sparing effect on statin therapy, potentially decreasing the risk of unwanted side effects or drug-drug interactions associated with statin use. This makes colesevelam a viable option for addition to a statin regimen when goal LDL-C levels cannot be achieved with a statin alone. Additionally, anecdotal reports indicate that colesevelam may have potential benefits in certain patient populations that cannot tolerate other lipid lowering therapies, including organ transplant recipients, cholestatic liver disesase, and end-stage renal disease. By recognizing the potential utility of colesevelam, clinicians can better manage those patients who are not able to tolerate first-line therapies.

Assessment of geriatric information on the drug label for commonly prescribed drugs in older people.

Older people contribute to a significant portion of all prescription drug use and expenditures in the United States. Despite this, older people are often excluded from clinical trials examining the safety and efficacy of drugs. It is unclear to what extent drugs commonly used in older people contain information about prescribing in older people on their product labeling. The objective of this study was to determine the availability of pharmacokinetic, safety, and dosing information with reference to older people on product labels or package inserts (PIs) for commonly prescribed drugs in patients aged 65 and older. The top 50 oral drugs prescribed at the University of Pittsburgh Medical Center were identified through a computerized search of pharmacy records. PIs for these drugs were evaluated for information on elderly patients. Information on drug use in older people was found in 41 (82%) of the PIs. Drugs marketed after 1990 were more likely to contain information on geriatric use, with pharmacokinetic information being the most common type. Approximately 50% of the PIs contained precautionary statements for older people, but most did not provide any specific problems that might be encountered in this population. Only 28 (56%) PIs had dosing information available, and of these, just eight provided specific milligram recommendations for elderly patients. This analysis provides evidence that more should be done to improve the availability of prescribing information, particularly dosing and safety, on drug labels for older people. Additional regulatory action requiring this information to be included on drug product labels may be warranted.

Colesevelam hydrochloride.

The pharmacology, pharmacodynamics, clinical efficacy, drug interactions, adverse effects, and dosage and administration of colesevelam hydrochloride are reviewed. Colesevelam hydrochloride is a nonabsorbed lipid-lowering agent approved for use alone or in combination with hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors for the reduction of low-density-lipoprotein (LDL) cholesterol in patients with primary hypercholesterolemia. Colesevelam forms nonabsorbable complexes with bile acids in the gastrointestinal (GI) tract, resulting in changes in plasma lipid levels, including total, LDL, and high-density-lipoprotein cholesterol and triglycerides. Colesevelam has been reported to be four to six times as potent as traditional bile acid sequestrants (BASs), perhaps because of its greater binding affinity for glycocholic acid. Unlike cholestyramine and colestipol, colesevelam appears to reduce LDL cholesterol in a dose-dependent manner. In clinical trials, colesevelam demonstrated efficacy either alone or in combination with HMG-CoA reductase inhibitors in the treatment of primary hypercholesterolemia. Combination therapy appeared to be more effective than monotherapy. Although infection, headache, and GI adverse effects have been reported for colesevelam, the rates do not differ significantly from those occurring with placebo. The constipation that typically hinders compliance with traditional BASs is minimal. In one study, the rate of compliance with colesevelam was 93%. There is little evidence of clinically significant interactions involving colesevelam. The maintenance dosage is three 625-mg tablets twice daily or six tablets once daily, taken with meals. Colesevelam provides an effective alternative to cholestyramine and colestipol while offering the potential for fewer adverse effects and better compliance. Studies are needed to directly compare colesevelam with traditional BASs.