Ionis Pharmaceuticals reported robust second quarter 2025 financial results, with total revenue doubling to $452 million compared to $225 million in the same period last year. The strong performance was driven primarily by the successful commercial launch of TRYNGOLZA (olezarsen), the company's first independently launched medicine, which generated $19 million in net product sales during its second full quarter on the market.
"During the second quarter, we continued to build momentum across our business," said Brett P. Monia, Ph.D., chief executive officer of Ionis. "Our strong performance included excellent commercial execution, resulting in a substantial increase in TRYNGOLZA revenues, our first independently launched medicine."
Financial Performance Drives Guidance Increase
Based on the strong performance, Ionis raised its 2025 financial guidance for the second time this year. The company increased its total revenue guidance to $825-850 million from the previous range of $725-750 million. TRYNGOLZA product sales are now expected to reach $75-80 million for the full year 2025.
The company's operating loss on a non-GAAP basis is projected to improve significantly to $300-325 million, compared to the previous guidance of less than $375 million. Cash, cash equivalents and short-term investments are expected to reach approximately $2.0 billion, up from the previous estimate of $1.9 billion.
"For the second time this year, we are significantly raising our 2025 financial guidance — this time driven by an improved outlook for the year and strong revenue performance to date, which includes the early launch excellence with TRYNGOLZA," said Elizabeth L. Hougen, chief financial officer of Ionis.
TRYNGOLZA Gains European Approval Pathway
TRYNGOLZA, approved by the FDA as an adjunct to diet to reduce triglycerides in adults with familial chylomicronemia syndrome (FCS), received a positive opinion from the Committee for Medicinal Products for Human Use (CHMP), paving the way for European market access. The drug generated $26 million in net product sales for the first half of 2025.
The company also announced positive topline results from the Essence study in people with moderately elevated triglycerides, achieving primary and all key secondary endpoints for both 80 mg and 50 mg monthly doses with favorable safety and tolerability profiles.
Pipeline Advances and Upcoming Catalysts
Donidalorsen, Ionis' investigational treatment for hereditary angioedema (HAE), is positioned for launch later this year with a U.S. PDUFA date of August 21, 2025. The drug is designed to be the first and only RNA-targeted prophylactic therapy offering durable efficacy with monthly or every-other-month dosing via autoinjector.
"We expect additional advancements in the second half, including Ionis' second independent launch with donidalorsen for hereditary angioedema, anticipated next month, and important Phase 3 results for olezarsen in severe hypertriglyceridemia and zilganersen in Alexander disease," Monia stated.
Olezarsen is on track for topline Phase 3 data from the pivotal CORE and CORE2 studies in patients with severe hypertriglyceridemia (sHTG) in September 2025, potentially positioning the drug to treat a more prevalent patient population with high unmet medical need.
Partnered Medicine Performance
WAINUA (eplontersen), developed in partnership with AstraZeneca for hereditary transthyretin-mediated amyloidosis, generated sales of $44 million in the second quarter, resulting in $10 million in royalty revenue for Ionis. The drug continues expanding globally with new launches underway in numerous regions, including the EU.
SPINRAZA (nusinersen), partnered with Biogen for spinal muscular atrophy treatment, generated global sales of $393 million in the second quarter, contributing $54 million in royalty revenue to Ionis. A higher dose formulation of nusinersen is under review for marketing approval in both the U.S. and EU.
Strategic Pipeline Development
The company initiated the Phase 3 REVEAL study of ION582 for Angelman syndrome, a serious and rare neurodevelopmental disorder. Additionally, AstraZeneca initiated a Phase 2b study of opemalirsen for APOL1-mediated kidney disease, triggering a $30 million milestone payment to Ionis.
Biogen will advance salanersen into registrational studies based on positive interim Phase 1 results in SMA patients, with the potential for annual dosing using novel Ionis antisense chemistry. Phase 1 data showed substantial slowing of neurodegeneration and clinically meaningful improvements in patients previously treated with gene therapy.
Monia emphasized that the four key programs—TRYNGOLZA, donidalorsen, olezarsen, and zilganersen—"collectively represent multi-billion-dollar revenue potential and a transformational opportunity for Ionis and for patients."
