Financial Data and Key Metrics Changes - For Q4 2025, the company reported U.S. net product sales of $126.6 million, with total net product sales for the full year reaching $410.5 million, marking significant year-over-year growth [24][29] - FILSPARI generated approximately $103 million in net product sales for Q4 2025, resulting in $322 million for the full year, representing a 144% year-over-year growth [19][24] - The company achieved a net income of $2.7 million for Q4 2025, compared to a net loss of $60.3 million for the same period in 2024 [29] Business Line Data and Key Metrics Changes - FILSPARI saw record demand with 908 new patient starts in Q4 2025, driven by strong physician adoption and confidence in its role as a foundational therapy in IgA nephropathy [18][19] - Thiola and Thiola EC contributed $23.3 million in U.S. net product sales during Q4 2025, totaling $88.5 million for the full year [25] Market Data and Key Metrics Changes - The company noted that over 96% of the patient population has a pathway to reimbursement for FILSPARI, maintaining a strong position in payer boundaries despite new competition [37] - There is increasing adoption of FILSPARI among patients with proteinuria levels below 1.5 grams per gram, which represents approximately two-thirds of the addressable IgA nephropathy population [21] Company Strategy and Development Direction - The company aims to solidify FILSPARI's foundational role in IgA nephropathy, successfully deliver the first approved medicine for FSGS, and advance enrollment in the Phase 3 HARMONY Study [9][30] - The strategy includes building a durable, growing rare disease company grounded in execution and scientific rigor, with a focus on delivering meaningful progress for patients [9][32] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in the clinical profile of FILSPARI as a potential FSGS therapy, despite a shift in the FDA's PDUFA action date to April 13, 2026 [8][12] - The company anticipates continued strong demand for FILSPARI and expects meaningful net product sales growth in 2026, despite modestly higher gross to net discounts [30][31] Other Important Information - The company has resumed activating clinical trial sites for the Phase 3 HARMONY study for pegtibatinase, which is designed to evaluate sustained total homocysteine control in classical homocystinuria [16] - The company reported a total of approximately $322.8 million in cash, cash equivalents, and marketable securities as of December 31, 2025 [29] Q&A Session Summary Question: Can you provide more detail on the IgA performance and how the product is being prescribed? - Management noted that demand was driven by modifications in REMS requirements and the publication of KDIGO guidelines, with the majority of utilization occurring in community-based nephrologists [35][37] Question: Have you had more significant data requests from the FDA? - Management confirmed ongoing engagement with the FDA and stated that they are on track for the April 13 action date, without providing specific details on the nature of the requests [46] Question: What proportion of new patient starts came from patients with proteinuria less than 1.5 grams per gram? - Management indicated that there is an increasing proportion of patient start forms with proteinuria levels below 1.5, although specific percentages were not disclosed [50][53] Question: What are your plans for communicating with the investor community as you approach the FSGS PDUFA? - Management stated they will enter a quiet period and provide updates following any material communication from the FDA regarding the PDUFA action [85] Question: Can you set expectations for first quarter demand relative to Q4 2025? - Management expressed confidence in strong demand exceeding 900 new patient starts but cautioned about variability in a rare disease market [90]