Investment in rare disease biotechs is picking up in the U.S. following the renewal of FDA's Priority Review Voucher (PRV) program, according to SynaptixBio.

The report comes as the UK’s rare disease sector continues to struggle to attract comparable capital, with the gap between the two markets emerging as a defining storyline for an industry racing to bring treatments to the roughly one in 17 people who will be affected by a rare disease during their lifetime.¹

The PRV program was signed into law back in February this year and will remain in place until it comes up for review again in September 2029, giving biotech’s and investors several years of policy certainty to work with.

What is fueling the shift?

According to VC firm V-Bio, "Reauthorization of FDA's Rare Pediatric Disease Priority Review Voucher (PRV) scheme has restored financial certainty and sparked intense interest from large pharma."²

PRVs are considered a prime source of non-dilutive capital, so when a voucher is sold, the generated cash doesn’t require the seller to issue new equity, making it an attractive mechanism for cash-strapped rare disease developers.¹

Dan Williams PhD, chief executive officer at leading rare disease biotech SynaptixBio, noted that the voucher itself is what sets the U.S. apart. "The U.S. dominates because the PRV program creates a highly valuable and, more importantly, tradable asset," he said. "VCs and private equity firms are far more willing to invest in rare disease biotechs simply because they provide a financial return on investment."

According to SynaptixBio, PRVs have recently sold for anywhere between $150 million and $200 million.

Why is the UK falling behind?

Williams argues the absence of an equivalent scheme is what holds the UK back. "While the UK is known for high-quality science and innovation, it has seen a sharp contraction in biotech fundraising. Without an equivalent to FDA's PRV program, UK rare disease biotech’s will rely heavily on public markets, private investment, or acquisition by larger global pharma to secure capital."

Market analysis published by Schroders back in April pointed to a longstanding structural problem. "With public markets grappling with valuation volatility, the UK's 'golden triangle' of innovation, spanning London, Oxford, and Cambridge, continues to produce the next generation of biotech champions," the analysis noted. "Historically, the UK's Achilles' heel has been the 'Valley of Death,' the gap between brilliant seed-stage science and the massive capital required for clinical trials. Too often, UK companies were forced to list in New York just to access the depth of capital needed to scale."³

Why does pharma want rare disease assets?

Sergey Jakimov, founding partner at specialist biotech VC firm LongeVC, says orphan therapies are becoming too significant to ignore. "Orphan therapies are already projected to be roughly a fifth of global prescription revenue. Pharma needs de-risked, clinically validated assets, and rare disease programs tend to show up better in diligence, clearer endpoints, smaller trials, engaged patient communities, and a higher likelihood of approval from Phase I."⁴

Jakimov points to the underlying biology as a further advantage. "You usually know the gene, you know the protein, and you know the patient. When a modality finally catches up to the biology, such as AAV gene therapy, ASOs, siRNA, base and prime editing, you can move from target ID to a clinical hypothesis in a shorter time span."

Is the UK's new framework enough?

In the UK, the Medicines & Healthcare Regulatory Agency is consulting on a new regulatory framework intended to bring rare disease drugs more quickly to market. Williams welcomes the move but says it does not go far enough on its own. "It would be ideal if the UK could introduce a scheme similar to the PRV. With the proposed new framework we have everything in place to better manage the clinical trial and marketing authorization process for rare disease therapies, but it stops there.”

Williams continued to say, “Reducing regulatory and approvals timescales and costs can only be good for rare disease patients and their families, but adding this stronger incentive could transform the industry, making the UK a leading player in research and development in this key area."

Sources

1. Investment in rare disease biotechs increasing since PRV scheme renewal, says leading biotech, but UK lagging SynaptixBio August 10, 2026, https://www.synaptixbio.com/
2. The FDA Reset and its Ripple Effect on European Biotech V-Bio December 16, 2025, https://www.v-bio.ventures/the-fda-reset-and-its-ripple-effect-on-european-biotech/
3. The $1tn+ opportunity for UK biotech Schroders April 27, 2026, https://www.schroders.com/en-ch/ch/professional/insights/the-1tn-opportunity-for-uk-biotech/
4. 8 VCs Funding Rare Disease Startups in 2026 Cure June 4, 2026, https://wewillcure.com/insights/company-profiles/rare-diseases/vcs-funding-rare-disease-startups-in-2026