Orphan drugs principles

It is often important to establish that a company s medicine for which it desires an orphan drug designation differs from another medicine. There are a number of principles that will help a company establish a difference. 

It is obvious that arthritis, epilepsy, depression, asthma and other similar diseases are not rare and drugs to treat them do not qualify for orphan drug designation. But would a medically plausible subset of each disease qualify as an orphan indication if there were fewer than 200 000 patients with, for example, a severe form of the disease The FDA s principle in addressing this common question is to ask the question Could (and would) patients with less severe forms of the disease use the new treatment If so, then the FDA says that the indication is not a true orphan and usually denies the application for orphan designation. 

Although new and iimovative formulations are urgently needed, work on extemporaneous formulations should not be disregarded, as this is stiU an activity of vital importance in many hospital pharmacies that collaborate with physicians in trials and who also work with orphan drugs. Hence the principles of formulation and manufacture espoused in this book are clearly relevant not only to those who work in industry but also to those who practice closer to the patient. 

One of the most important principles about orphan drugs is that they form a very heterogeneous group, for the reasons given in Table 18.1. 

Variable commercial potential and low medical value. Most orphan drugs, at an early stage of their development, are of this type because the clinical efficacy and safety profiles are not well understood. One exception to this principle is drugs that are developed in a new dosage form, but whose activity and safety are well known, where there is usually more certainty about the medical value. Me-too drugs are usually of low medical value as candidates for orphan designation and are rarely developed for rare diseases. 

---