text: According to Thomson Reuters in their 2012 publication "The Economic Power of Orphan Drugs", there has been increased investment in orphan drug research and development, partly due to the U.S. Orphan Drug Act of 1983 (ODA) and similar acts in other regions of the world driven by "high-profile philanthropic funding".
  According to Drug Discovery Today, the years 2001 to 2011 were the "most productive period in the history of orphan drug development, in terms of average annual orphan drug designations and orphan drug approvals". For the same decade the compound annual growth rate (CAGR) of the orphan drugs was an "impressive 25.8%, compared to only 20.1% for a matched control group of non-orphan drugs". By 2012, the market for orphan drugs was worth US$637 million, compared with US$638 million for a control group of non-orphan drugs.
  By 2012,
  According to a 2014 report, the orphan drug market has become increasingly lucrative for a number of reasons. The cost of clinical trials for orphan drugs is substantially lower than for other diseases because trial sizes are naturally much smaller than for more diseases with larger numbers of patients. Small clinical trials and minimal competition place orphan agents at an advantage in regulatory review.
  Tax incentives reduce the cost of development. On average the cost per patient for orphan drugs is "six times that of non-orphan drugs, a clear indication of their pricing power". The cost of per-person outlays are large and are expected to increase with wider use of public subsidies.
  The 2014 Orphan Drug report stated that the percentage of orphan drug sales as part of all prescription drug sales had been increasing at a rapid rate. The report projected a total of US$176 billion by 2020. Although orphan disease populations are the smallest, the cost of per-patient outlays among them are the largest and are expected to increase as more people with rare diseases become eligible for subsidies – in the U.S., for example, through the Affordable Care Act.