In comparison with major diseases, the targeting of rare diseases poses many different challenges, necessitating consideration of bespoke R&D strategies for drug discovery efforts to be successful. This report examines the role that low disease prevalence plays in determining the most suitable R&D path.
Features and benefits
Understand the growing interest in developing new treatments for rare diseases, and why low patient numbers do not preclude commercial viability.
Review the regulatory environment governing the development of orphan drugs in different countries.
Identify the key challenges that are presented by low patient prevalences.
Assess how the research strategy chosen can be influenced by the disease prevalence.
Compare the scenarios in which repurposing of existing drugs offers advantages over the development of novel drugs, and vice versa.
Approximately 7,000 rare diseases have been identified, but only a very small proportion of these are currently well treated. Orphans represent a greater proportion of all new BLAs than they do of NMEs submitted as NDAs. Most orphan approvals are not first approvals of new drugs but are new orphan indications for previously approved drugs.
It is possible to obtain orphan drug designation for conditions with a total prevalence greater than that defined by legislation, but only if medically justifiable subsets can be defined with a lower (overall) prevalence. Pediatric subsets are most commonly used.
In the development of new treatments for rare diseases it is less critical to seek to optimize the pharmacokinetic properties of candidates than is the case for common chronic diseases, with parenteral delivery or frequent oral dosing being much more acceptable provided that efficacy is achieved.
Your key questions answered
What impact on R&D strategy does disease prevalence have on moving from rare through very rare to ultra rare diseases?
Can more than one drug be a commercial success for treating rare indications, and how do drug regulators view the question of drug similarity?
What are the best ways of identifying patients for recruitment into clinical trials for drugs designed to treat rare diseases?
What are the requirements for a clinical candidate to treat a rare disease?
What factors determine whether a small-molecule or biologic strategy is most suitable when targeting a rare disease?