The U.S. House of Representatives has passed legislation to reauthorise a key Food and Drug Administration programme designed to encourage the development of medicines for rare diseases, reviving a scheme that had lapsed amid debate over its cost and impact.
The bill, passed on Dec. 1, extends the FDA’s Priority Review Voucher (PRV) programme, which offers drug developers the option of faster regulatory review for qualifying medicines or the ability to sell the voucher to another company. The programme includes a sunset clause, requiring periodic reauthorisation by Congress.
Reauthorisation stalled in December 2024 as lawmakers questioned whether the programme still serves public health goals, particularly given the soaring market value of the vouchers and concerns about whether they meaningfully accelerate access to treatments for patients.
Supporters argue the programme remains critical for companies working on rare and paediatric diseases, where development costs are high and patient populations are small.
“Developing therapies for rare diseases is a moral imperative,” said Dan Williams, chief executive officer of SynaptixBio, a U.S.-based biotechnology company developing treatments for rare neurological conditions. “Whilst individually rare, together millions worldwide are affected.”
Williams said the PRV programme provides smaller biotechnology firms with a financial incentive to invest in lengthy and risky drug development pipelines. “The PRV scheme means smaller biotechs can see a meaningful return on the very high investment needed to develop and take a rare disease drug through clinical trials,” he said.
The legislation, known as the Mikaela Naylon Give Kids a Chance Act, will next be considered by the U.S. Senate. If approved, it would be sent to President Donald Trump for final sign-off.
Originally authorised in 2007 to stimulate treatments for neglected tropical diseases, the PRV scheme was expanded in 2012 to include rare paediatric diseases. A voucher allows companies to shorten the FDA review timeline for a drug application from about 10 months to six months, a commercially valuable advantage in competitive markets.
PRVs have become highly sought after and expensive. In August 2024, Ipsen sold a voucher for $158 million after receiving it through approval of a rare disease medicine. In May, Abeona Therapeutics sold another for $155 million just weeks after obtaining it for a gene therapy approval.
SynaptixBio currently holds two rare paediatric disease designations from the FDA — one for hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC), a rare and fatal neurological disorder, and another for isolated hypomyelination, a related condition. Such designations can make a company eligible for a PRV if a drug is approved.
Earlier this year, the company selected a lead drug candidate based on antisense oligonucleotide technology, which works by silencing disease-causing genes without altering the gene itself.
Williams said innovation in rare disease research has largely come from smaller firms, while larger pharmaceutical companies tend to focus on drugs with broader commercial markets. He added that partnerships often emerge later, once early-stage risks have been reduced.
“Once a smaller biotech’s candidate orphan drug has entered clinical trials, larger companies’ strengths in regulation, manufacturing and market access become important,” he said.
Critics of the PRV programme have argued that high voucher prices reward companies without guaranteeing improved access or affordability for patients. Supporters counter that without such incentives, many rare disease therapies would never be developed.
The Senate debate is expected to determine whether the programme continues in its current form or faces further reform.
