Incremental innovation improves patient health; a world of ideas on public policy. (pfizer forum).(Brief Article)

The process of repeated incremental improvement is the predominant mechanism of innovation and product development within most manufacturing and high-technology companies, including pharmaceutical companies. In fact, the history of clinical pharmacology is characterized by incremental improvements in the safety, efficacy, selectivity, and utility of drugs within a given class. Some critics believe that these incremental advances are too costly and do not ultimately benefit the consumer. In this view, new agents in a class are merely "me-too" drugs with no significant differences from the original agents. This is a misconception. The new medicines resulting from this evolutionary process can offer advantages in terms of improved efficacy, better patient satisfaction and compliance and, in many cases, cost savings.

The existence of multiple agents within a given drug class offers many advantages. One is the availability of alternative agents in cases of treatment failure, and of backup in case an agent is withdrawn from the market. The development of drug product classes is analogous to the evolution of biological species, and the advantages of diversity within groups of pharmaceutical products (i.e., "pharmacodiversity") are similar to the advantages of biodiversity. Within a drug class, products with varying features compete for patients. The emergence of new disease and patient targets expands the role of some agents; others are disadvantaged by newly discovered adverse effects. Thus, those products that are the best "fit" for their environment dominate the marketplace. Other products may become extinct and still others maintain positions in "niche markets."

The availability of multiple agents within a drug class also makes it possible to vary dosage delivery systems and dosage forms, which in turn allows extended uses with a variety of patient populations. Advanced delivery systems provide sustained therapeutic drug levels for long periods of time, can enable the use of smaller or fewer doses, allow a less invasive mode of administration, and prolong circulation of short lived compounds. Newer drugs in a therapeutic class often represent improvements in therapeutic and adverse effects profiles, metabolism, dosing schedules, ease of administration, and other features. These findings apply to drug classes used to treat many common diseases and patient groups, especially the elderly.

Moreover, patient responses to and toleration of agents are subject to great individual variations. The availability of a broad range of medicines gives physicians a "tool chest" for treating the individual needs of diverse patients ...