Third, through the advancement of our early-stage pipeline with AG-236 and AG-181, we have the potential to unlock future value in hematologic and other rare diseases. And finally, we remain committed to long-term sustainability, supported by disciplined capital allocation and continued operational efficiency. Building on those priorities, the next slide maps key pipeline catalysts in 2026 across multiple high-value indication opportunities. These milestones and continued progress in our early-stage pipeline position the portfolio for growth and long-term value creation.
We exited 2025 with solid momentum across the business, commercial execution, pipeline progress, and continued focus on financial discipline, which together provide a strong foundation to deliver on our 2026 strategic priorities. Starting with commercial performance, PYRUKYND delivered $20 million in net revenue in the fourth quarter, bringing full-year 2025 revenue to $54 million, reflecting robust year-on-year growth. launch, pursue the path forward for mitapivat in sickle cell disease, and continue to advance our pipeline programs. Please move to the next slide, and I'll turn the call over to Cecilia to provide additional details on our 2025 fourth quarter and full year performance, as well as our 2026 outlook.
R&D expenses were $88.1 million, an increase of $5.3 million compared to the fourth quarter of 2024, associated with the advancement of our earlier-stage pipeline program. As a reminder, in future quarters, we will report mitapivat revenue as a whole, breaking out U.S. This guidance assumes investment to maximize launch of ACTIVASE in thalassemia in the U.S., gated investment for sickle cell disease, and operating model refinement. Fourth quarter ex-US revenue was roughly $4 million, which primarily reflects supply ahead of demand pull-through, as PK deficiency patients in Europe transition onto commercial supply.
| Metric | Period | Current guidance |
|---|---|---|
| U.S. PK deficiency revenue | FY2026 | $45-$50 million |
| Operating expenses | FY2026 | roughly flat with 2025 |
| Ex-U.S. revenue | Q1 2026 | sequential decline expected |
| Thalassemia gross-to-net | FY2026 | 10%-20%, similar to PK deficiency |
| Prescription-to-treatment-initiation time | early launch quarters | average 10-12 weeks, expected to shorten as launch progresses |
| Metric | YoY | Note |
|---|---|---|
| Worldwide PYRUKYND revenue | +86% | Continued PK deficiency demand ahead of ACTIVASE approval, an additional ordering week in Q4, and favorable gross-to-net adjustments |
| R&D expense | +$5.3M | Advancement of earlier-stage pipeline programs |
| SG&A expense | roughly flat | $51.6M in Q4, roughly flat year-over-year |
| Topic | Previous mention | Current period | Trend |
|---|---|---|---|
| ACTIVASE thalassemia U.S. launch | Pre-launch planning ahead of FDA approval | Launch underway with 44 early prescriptions, community-physician-led prescribing, and no REMS barrier observed | — |
| Mitapivat in sickle cell disease | Reported RISE UP phase III top-line data in Q4 | Pre-sNDA meeting planned for Q1 2026 to define the regulatory path, targeting full approval | — |
| Tebapivat pipeline | Two phase II trials ongoing | Lower-risk MDS phase 2b top-line data expected H1 2026; sickle cell disease enrollment complete with top-line data expected H2 2026 | — |
| Path to profitability | Goal of becoming a sustainable rare disease company | Clear path to profitability through existing thalassemia and PK deficiency franchises, supported by disciplined OpEx management | — |
| Ex-U.S. commercialization | Global managed access program providing PYRUKYND free of charge | Transition to commercial supply via Advanz (Europe) and NewBridge (GCC); potential EC decision in coming months after Oct 2025 CHMP opinion | — |