Shares of Regeneron plunged 13% to $659.42 as investors digested a new competitive threat to the company's already-shrinking eye-drug empire. The catalyst: Kodiak Sciences saw its stock surge approximately 145% on September 28 after announcing successful Phase 3 DAYBREAK results , with both of Kodiak's candidates matching Eylea in wet age-related macular degeneration after one year of treatment. The selloff compounds a brutal 2026 for Regeneron shareholders, who were already watching the Eylea franchise bleed out.

  • A Rival Offering Fewer Needle Sticks Changes the Math. The real danger isn't that Kodiak matched Eylea's vision results — it's how it did so. Kodiak's lead drug was able to match Eylea's eyesight improvement using an individualized dosing strategy that allowed more than half of trial participants to receive injections only once every six months, compared with once every eight weeks for Eylea. For patients getting needles in their eyes, that difference is enormous. Kodiak plans to file for FDA approval in Q4 2026.

  • Eylea Was Already in Steep Decline. This competitive blow lands on a franchise already under siege. In Q1 2026, the Eylea franchise generated $941 million in the U.S., a 10% year-over-year decline — the first time since 2018 that quarterly U.S. sales fell below $1 billion.

Biosimilar copies from Amgen and Samsung Bioepis launched in 2024 and 2025 , and the Eylea franchise historically contributed close to 40% of Regeneron's net product sales. Kodiak now adds a branded competitor with a potentially superior convenience profile.

  • Dupixent Is Growing But Must Do More Heavy Lifting. Regeneron's allergy and asthma blockbuster Dupixent remains a bright spot. Q2 2026 revenues rose 17% to $4.3 billion, with Dupixent global sales jumping 38% to a record $6.0 billion. But with Eylea shrinking and the company's cancer-drug combination failing a key Phase 3 melanoma study earlier this year , the burden on a single drug to power growth is intensifying.

  • The Street Was Already Losing Patience. Analyst downgrades compounded the decline — Citi cut Regeneron to Neutral and slashed its target to $700 from $900, while at least 10 brokerages reduced price targets following the oncology miss. The current consensus target sits around $748, with a range of $504 to $940. At $659, the stock now trades below even the reduced midpoint, signaling the market is pricing in further franchise erosion rather than a rebound.