Search

Genomics - having quickly emerged as the central discipline in basic science and biomedical research - is poised to take the center stage in clinical medicine as well over the next few decades. Although there is no specific regulatory guideline on the application of pharmacogenetics to drug development, some recommendations are already included in several published guidelines on drug development. The patients more likely to provide the most valuable information on the specific contribution of a given gene or its variant are those who fail to respond to a drug ('therapeutic failures') and those who develop toxicity to the drug. However, before drawing definite conclusions on subgroups following pharmacogenomic analyses, one must be aware of disease classification, data collection, and how much is known about the disease process. It seems reasonable to collect genomic DNA from all patients enrolled in clinical drug trials (along with appropriate consent to permit pharmacogenetic studies) for the purpose of post hoc analyses. One exception to post hoc genomic analysis is when patients with a specific genotype are excluded from randomization into a clinical trial. Physicians will need to understand the concept of genetic variability, its interactions with the environment (e.g. drug-drug or drug-disease interactions), and its implication for patient care.

The relative toxicities of amantadine and rimantadine were compared in a double-blind, placebo-controlled study involving healthy adults. In separate studies, drugs were administered at a dosage of 200 mg/day (52 volunteers) or 300 mg/day (196 volunteers) for 4.5 days. Both drugs were well tolerated at the lower dosage. At 300 mg/day amantadine recipients had a greater frequency and severity of central nervous system (nervousness, lightheadedness, difficulty concentrating) and sleep (insomnia, fatigue) complaints compared with rimantadine or placebo recipients. Amantadine recipients also performed less well on an objective test measuring sustained attention and problem-solving ability. Both amantadine and rimantadine recipients reported adverse gastrointestinal symptoms more often than placebo recipients. Because of better tolerance at higher dosage, rimantadine offers more promise than amantadine for treatment of influenza A virus infections.

The prophylactic activity of intranasal human interferon-alpha 2 (HuIFN-alpha 2) against natural rhinovirus colds was determined in a randomized, double-blind, placebo-controlled trial. A total of 304 working adults self-administered sprays of HuIFN-alpha 2 (10(7) IU/day) or a placebo once daily. During 22 days of treatment, 13 (8.5%) placebo recipients but no HuIFN-alpha 2 recipients had respiratory illnesses documented secondary to rhinovirus infection (P = 0.0002). The occurrence of illness with symptoms of tracheobronchitis was lower in HuIFN-alpha 2 recipients (one eposide) than in placebo recipients (eight episodes, P = 0.04). In contrast, the frequency of nasal symptoms and the overall rate of respiratory illness were significantly higher in HuIFN-alpha 2 recipients during weeks 2 and 3 of treatment. Symptoms (obstruction, discomfort, blood-tinged nasal mucus) or signs (punctate bleeding sites, erosions, superficial ulcerations) of nasal irritation occurred in 40 HuIFN-alpha 2 recipients during week 3 (P less than 0.0001 versus placebo recipients). Although the results of the current study were partially confounded by the nasal side effects of prolonged administration, they showed that intranasal HuIFN-alpha 2 was efficacious in preventing rhinovirus colds under natural conditions.