TLDR

  • IONS stock slides 2.23% to $42.93 despite Roche’s Phase 3 kidney trial success.

  • Roche’s sefaxersen cuts proteinuria 43.1% in a key Phase 3 kidney disease trial.

  • Ionis shares rebound 2.33% after hours to $43.93 following regular-session losses.

  • Phase 3 data show stronger hematuria resolution with sefaxersen versus placebo.

  • Roche targets regulators as its kidney trial continues toward week 105 results.

Ionis Pharmaceuticals (IONS) stock fell 2.23% to $42.93, losing $0.98 during regular trading before rebounding 2.33% to $43.93 after hours. The decline came despite positive Phase 3 kidney disease trial results from its partner, Roche. The study showed that experimental treatment sefaxersen significantly reduced proteinuria in patients with primary IgA nephropathy.

\Ionis Pharmaceuticals, Inc., IONS

Roche Reports 43.1% Proteinuria Reduction in Phase 3 Kidney Trial

Roche reported positive results from the ongoing Phase 3 IMAgINATION study involving adults with primary IgA nephropathy. The trial evaluated sefaxersen alongside optimized standard care and compared its effectiveness against a placebo. At week 37, the treatment achieved a statistically significant 43.1% reduction in proteinuria relative to placebo.

The study recorded a 95% confidence interval between 32.5% and 52.0%, with a P-value below 0.0001. Researchers measured treatment effectiveness through the 24-hour urine protein-to-creatinine ratio, a key marker of kidney damage. Moreover, lower proteinuria levels generally correlate with better long-term kidney function.

Roche presented the findings during the American Society of Nephrology Kidney Week 2026 conference. Additionally, more patients receiving sefaxersen experienced resolution of blood in their urine compared with placebo recipients. The treatment also demonstrated consistent effectiveness across predefined patient subgroups without introducing new safety concerns.

Ionis Pharmaceuticals Advances Kidney Treatment Through Roche Partnership

Ionis developed sefaxersen as an RNA-targeted treatment that reduces factor B production in the liver. Factor B contributes to alternative complement pathway activity, which plays a role in IgA nephropathy. By reducing this protein, sefaxersen targets a biological process associated with kidney inflammation and damage.

The experimental medicine uses monthly injections beneath the skin and supports potential self-administration by patients. Meanwhile, Roche continues the blinded IMAgINATION study to measure changes in kidney function over two years. Researchers will assess estimated glomerular filtration rate at week 105 to evaluate longer-term treatment outcomes.

Roche licensed sefaxersen from Ionis under an agreement covering complement-mediated diseases. Ionis previously received upfront payments, licensing fees, and development milestone payments through the partnership. Furthermore, the agreement provides potential regulatory milestones, sales milestones, and tiered royalties on future net sales.

IONS Stock Declines as Roche Prepares Regulatory Discussions

Despite the clinical progress, Ionis shares finished regular trading lower before recovering part of their losses after hours. The contrasting price movements followed Roche’s announcement of the latest Phase 3 findings. However, the available trading information does not establish a specific cause for the regular-session decline.

IgA nephropathy causes progressive kidney damage and commonly affects adults before age 40. The disease affects at least 25 adults per million worldwide annually and can eventually cause kidney failure. Within 20 years of diagnosis, up to half of affected patients may develop end-stage kidney disease.

Roche plans to share the latest trial findings with health authorities to support further development discussions. Meanwhile, the ongoing study will provide additional evidence about sefaxersen’s effects on kidney function. Regulatory decisions and future commercial milestones will determine the treatment’s potential contribution to Ionis Pharmaceuticals’ business.

 

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