CDER initiatives striv to improve drug safety

Presenting an overview of the steps that have contributed to that goal, Dr. Chambers highlighted the critical path initiative, programs focusing on pediatric and geriatric populations, recent efforts to strengthen the safety program at the FDA, and pending approvals as they relate to pharmaceuticals for ophthalmic use.

The critical path initiative is an attempt to bring attention and focus to the need for targeted scientific efforts to modernize the techniques and methods used to evaluate the safety, efficacy, and quality of medical products as they move throughout the development process.

The initiative has three dimensions:

"Basically, this initiative was established for drugs or drug classes facing impediments in the development process that were preventing potentially safe and effective products from reaching the market," Dr. Chambers said.

Providing an example, he discussed the creation of the conjunctival antigen challenge model for clinical evaluation of the efficacy and safety of medications for treating allergic conjunctivitis. Prior to the introduction of that model, efficacy was tested in environmental studies. However, ocular anti-allergy medications were routinely failing in development because of difficulties encountered during those trials with variations in antigen exposure.

The conjunctival antigen challenge model, in which the antigen is placed directly onto the conjunctiva, provided a method for confirming patient eligibility and for achieving consistent results at any location and time of year. In addition, the studies could be designed to characterize drug onset of action, duration of response, and adverse events.

"With this model, testing could be performed indoors, independent of weather conditions, and with certainty that the product prevented the allergic response," Dr. Chambers said. "As a result, while 8 to 9 years ago steroids were essentially the only choice for treating allergic conjunctivitis, about 15 new products have come to the market for the treatment of allergic conjunctivitis since this model was introduced."

In the area of ophthalmology, work is ongoing to develop a chamber for testing products designed to treat dry eye.

In addition, researchers are trying to develop a model for studying systemic absorption of topical ophthalmic products that could be used to determine how much drug exits into the circulation from the eye.

For young and old Looking to address the paucity of pediatric studies, Congress enacted two bills in the past few years that have implications for bringing more safe and effective treatments to market for children. The first, enacted in 2002, was the Best Pharmaceuticals for Children Act (BPCA) that offers companies willing to do studies in pediatric patients a 6-month extension on patents and exclusivity.