Two Back-to-Back Phase 3 Wins Handed Ionis a 43% Rally — but Can a Royalty-Dependent Model Sustain the Surge?

Shares of Ionis Pharmaceuticals surged 43.3% to $62.96 on September 23, catapulting roughly $2.7 billion in market value onto a stock that had been languishing near 52-week lows just days earlier. The catalyst: two partnered drugs cleared their final-stage clinical hurdles in a 24-hour span, snapping what one analyst called a streak of trial failures that had defined Ionis's brutal 2026.

A Kidney Drug Partnered With Roche Hit Its Mark — and Entered a Crowded, High-Price Market. Sefaxersen met its primary endpoint in a 459-patient Phase 3 trial, significantly reducing protein in patients' urine — a key sign of kidney damage — at 37 weeks compared to placebo.

If approved, sefaxersen would face competition from drugs like Novartis's Fabhalta in a market where therapies are priced at roughly $400,000 to $500,000 a year.

Ionis is due up to $400 million in milestone payments plus tiered royalties — meaning Roche, not Ionis, controls pricing and sales execution.

An ALS Drug Gave Ionis Its First Phase 3 Win of the Year. Just one day earlier, ulefnersen showed a statistically significant improvement in functional impairment and survival in patients with a rare genetic form of ALS (p=0.0005).

This was the first Phase 3 win of "a brutal 2026 for Ionis" — arriving with the stock already down 18% in two weeks.

Otsuka licensed ulefnersen from Ionis in 2024 and holds commercialization rights. The ALS subtype is rare, so the near-term revenue prize is modest, but the credibility value is enormous after three consecutive mid-year failures.

The Stock Recovered Ground, but the Business Model Caps the Upside. Ionis held $2.1 billion in cash at June 30 and still targets cash-flow breakeven in 2028.

Full-year 2025 revenue was $943.7 million, up 34% year-over-year , yet the company remains unprofitable. Because both winning drugs are partnered out, Ionis collects milestones and royalties rather than full product economics. That dilutes the revenue impact of even blockbuster outcomes.

Analyst Targets Suggest Room to Run — With Caveats. Guggenheim recently cut its price target to $80, and Barclays to $85 , both well above today's price. But the pelacarsen heart-drug failure with Novartis in early September — once worth an estimated $13 per share — still looms. Investors are betting the pipeline has turned a corner; the next test is whether Roche and Otsuka can convert these wins into approvals fast enough to justify the rally.