Phase 3 RAINIER Results Supporting Best-in-Class Potential of Povetacicept in IgA Nephropathy Published in the New England Journal of Medicine and Presented at the American Society of Nephrology Kidney Week 2026

- Vertex is on track for the U.S. FDA Prescription Drug User Fee Act (PDUFA) date of November 30 for potential accelerated approval of povetacicept –

- Data published in NEJM and presented at ASN highlight povetacicept's unique trifecta of efficacy, favorable safety, and the simplicity of dosing at-home every 4 weeks with a low-volume autoinjector –

- Data presented at ASN include a qualitative study examining patient perspectives on current and emerging IgAN therapies, showing that 96% of participants preferred an autoinjector over a prefilled syringe, and 80% of participants preferred dosing every 4 weeks versus weekly dosing -

- New clinical studies of povetacicept underway including a study evaluating patient experience on povetacicept administered via autoinjector -

BOSTON, October 23, 2026--Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX) today announced the publication of Phase 3 RAINIER results for povetacicept in the New England Journal of Medicine (NEJM), presentation of these data at the American Society of Nephrology (ASN) Kidney Week 2026 in Denver, Colorado, and advancement of the povetacicept clinical research program in IgAN. Vertex will also host an investor event during ASN on October 23 at 6:15-7 p.m. MDT (8:15-9 p.m. EDT). Further details are below.

Data being presented include a pre-specified Week 36 interim analysis of the ongoing Phase 3 RAINIER trial of povetacicept, an engineered fusion protein and dual inhibitor of the BAFF (B cell activating factor) and APRIL (a proliferation inducing ligand) cytokines, in immunoglobulin A nephropathy (IgAN). RAINIER met its primary endpoint, with povetacicept achieving a 52.0% reduction from baseline in proteinuria at Week 36 and a statistically significant and clinically meaningful 49.8% reduction versus placebo (P<0.0001), while also meeting both secondary endpoints.

The Week 36 interim analysis of RAINIER demonstrated that the depth of proteinuria reduction from baseline was consistent across demographic, clinical and regional subgroups, including an unprecedented 54.2% reduction in urine protein to creatinine ratio (UPCR) versus placebo in North America. Additionally, findings showed that 42.2% of povetacicept-treated participants reached 24-hour UPCR <0.5 g/g, the threshold aligned with current Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, compared with only 6.2% on placebo. Importantly, these findings were observed on top of optimized supportive care in both treatment arms, including sodium-glucose co-transporter 2 (SGLT2) inhibitor use in 65.8% of participants, which is among the highest reported of any contemporary IgAN trial.