In 2020 orphan drugs are expected to account for 19% of the total share of prescription drug sales excluding generics, reaching $176 billion in annual sales, according to the new EvaluatePharma Orphan Drug Report 2014 from London-based market intelligence firm Evaluate.

At 11%, growth in the orphan drug market is set to be more than double the 5% growth rate of the overall prescription market excluding generics. In 2014, the average orphan drug cost per patient per year was $137,782 compared to an average of $20,875 for a non-orphan drug.

“Orphan drugs are no longer a niche segment of the market and are projected to account for 19% of the prescription drug market by 2020,” said Anthony Raeside, Evaluate’s head of research. “Although orphan populations are by definition the smallest, they represent big per-patient outlays and insurers will be looking carefully at new tools to arrest cost growth as more and more orphan drugs launch.”

Some of the report’s key findings include:

• A record 260 orphan drug designations were granted in the U.S. in 2013
• Orphan drug sales to grow 11% per year through 2020, compared to 5% for drugs (excluding generics) treating larger patient populations
• Phase III orphan drug development cost is half that of non-orphans, but development time for orphans is not shorter than for non-orphan drugs
• Anticipated return on investment for a phase III/filed orphan drug is 1.89 times greater than for a non-orphan drug.