Although the pace of approvals for new orphan drugs—medicines that treat relatively rare conditions—have increased in the U.S. and Europe in recent years, patients are facing growing challenges accessing those drugs, a newly completed study by the Tufts Center for the Study of Drug Development (CSDD) at Tufts University has concluded.

During the 14-year period from 2000 to 2013, 86 orphan drugs were approved in the U.S., up from 65 during the prior 18-year period (1983 to 2000), while in Europe 96 orphan drugs were approved from 2000 to 2013, more than double the 44 approved in the earlier period, according to Tufts CSDD.

Orphan drugs are those developed for rare diseases and conditions that affect fewer than 200,000 people in the U.S., or five per 10,000 or fewer people in the European Union.

Among the challenges that limit patient access to orphan drugs in the U.S., relative to Europe, is higher cost-sharing by patients, which can lead to increased levels of non-compliance, according to Joshua Cohen, assistant professor at Tufts CSDD, who conducted the analysis.

“The encouraging news is that more orphan drugs are in development today than ever before, with more getting marketing approval. In 2013 alone, nine orphan drugs were approved in the U.S., the most in a single year,” said Cohen. “But the high cost of these medicines is leading insurers to reassess their reimbursement policies, which likely will mean more out-of-pocket costs for patients.”

The most expensive orphan drugs can cost more than half a million dollars per year per patient in the U.S.

Key findings from the study, reported in the July/August Tufts CSDD Impact Report, include:

• Since 1983, 7% more orphan drugs have been approved in the U.S. than in Europe, and 17% more were approved first in the U.S. than were approved first in Europe.
• There are fewer denials of orphan drug coverage by U.S. payers than by European payers.
• While U.S. payers often require prior authorization as a condition of reimbursement, European health authorities employ more stringent conditions, such as on-label indication restrictions, step edits and coverage with evidence development.