title: Quantifying emerging drugs for very rare conditions.
abstract: BACKGROUND
  EU legislation is encouraging pharmaceutical companies to develop drugs for rare conditions, but their often high cost, and potential for long-term administration has led to debate about their affordability and cost-effectiveness.
  
  
  OBJECTIVE
  To investigate how many drugs are in development for very rare conditions.
  
  
  METHODS
  We defined very rare conditions as having a prevalence of <1:50,000, and identified pharmaceuticals in phase II, phase III trials or pre-registration for these conditions using commercial databases.
  
  
  RESULTS
  We identified 42 very rare conditions with at least one drug in late-stage clinical development, with a total of 113 drugs in development (17 for at least two indications). Sixteen drugs were pre-registration, 29 were in phase III development, 65 were in phase II development, one drug was both pre-registration and phase II for different indications and two drugs were in both phase II and phase III trials for different indications.
  
  
  CONCLUSIONS
  Not all the drugs in development will reach the market, but it is likely that a significant number will do so. Affordability and methods to assess cost-effectiveness will need debate and clear national policy for decision-makers to follow.
authors: Department of Public Health and Epidemiology, University of Birmingham, Birmingham, B15 2TT, UK. k.miles@bham.ac.uk
authors: K A
authors: KA
authors: Miles
authors: C
authors: C
authors: Packer
authors: A
authors: A
authors: Stevens
mesh_terms: D002986:Clinical Trials as Topic / Q000191:economics; D017322:Clinical Trials, Phase II as Topic; D017326:Clinical Trials, Phase III as Topic; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D008297:Male; D009965:Orphan Drug Production / Q000191:economics*; D035583:Rare Diseases / Q000188:drug therapy* / Q000191:economics / Q000517:prevention & control