Indication · Base-Rate Reference
Rare Disease / Orphan FDA Approval Rates
Historical first-cycle FDA approval rates for Rare Disease / Orphan assets across 8 regulatory pathways — NDA Standard, NDA Priority, BLA, sBLA, Class 2 Resubmission, Accelerated Approval, Breakthrough Therapy, Fast Track.
What's specific about Rare Disease / Orphan at FDA?
Orphan Drug Act flexibilities on endpoint choice and sample size drive higher first-cycle approval rates. Roughly half of all new molecular entities since 2018 have had orphan designation.
Rare Disease / Orphan base rates by pathway
| Pathway | First-cycle approval | Sample size | Typical clock | AdCom | Notes |
|---|---|---|---|---|---|
| sBLA | 85% | n~80 | priority 6 months | rarely | Pediatric and adjacent-indication expansions; high approval rates with concise supplements. |
| Breakthrough Therapy | 85% | n~80 | priority 6 months | sometimes | Breakthrough + orphan combination drives among the highest approval rates. |
| NDA Priority | 80% | n~150 | priority 6 months | sometimes | Strong first-cycle performance; CRLs typically CMC or confirmatory evidence adequacy. |
| BLA | 75% | n~60 | priority 6 months | sometimes | Enzyme replacement and gene therapy products; manufacturing inspections a frequent bottleneck. |
| Accelerated Approval | 75% | n~50 | priority 6 months | usually | Surrogate endpoint acceptance variable; AdComs increasingly convened for non-oncology rare disease. |
| NDA Standard | 72% | n~120 | standard 10 months | sometimes | Higher first-cycle approvals due to orphan flexibility on endpoints; CRLs often CMC-related. |
| Fast Track | 72% | n~120 | varies; often priority 6 months | sometimes | Widely used in rare disease; commonly paired with orphan and often accelerated approval. |
| Class 2 Resubmission | 70% | n~40 | 6 months from resubmission | sometimes | Additional data requests (confirmatory, CMC) drive resubmissions; generally successful when addressed. |
Base rates drawn from published FDA approval analyses covering roughly 2008-2022. Approximate — use as framing, not prediction.
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