## Latest Regeneron (REGN) News
**Regeneron shares experience sharp decline after mixed trial results for key COPD drug**
– Shares of Regeneron Pharmaceuticals (NASDAQ:REGN) plummeted nearly 19% on Friday, May 30, 2025, following the release of mixed results from two Phase 3 clinical trials of its experimental COPD drug, itepekimab, which is being developed in partnership with Sanofi. The AERIFY-1 study showed a 27% reduction in moderate or severe COPD flare-ups compared to placebo among 1,127 former smokers over 52 weeks. However, the AERIFY-2 trial failed to meet its main endpoint.
– The companies cited “lower-than-expected exacerbation rates” due to COVID-19 pandemic-related changes in respiratory infection exposure, which may have influenced the results. This outcome has cast significant uncertainty over the future of itepekimab, a drug previously projected to achieve peak annual sales of up to $5 billion. Both Regeneron and Sanofi are now reviewing the data and discussing possible next steps with regulators. Sanofi’s US-listed shares also dropped by around 5.5% on the news[2].
**Recent Institutional Moves in REGN**
– Jacobs & Co. CA increased its holdings in Regeneron by 9.3% in the first quarter of 2025, now owning over 10,000 shares valued at $6.37 million. Several other institutional investors have either increased or established new positions in REGN during recent quarters. As of the latest filings, institutional ownership stands at approximately 83.31%[1].
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### Top 3 Most Relevant Articles
#### 1. [Regeneron shares plunge after mixed COPD drug trial results]
**Content:** Regeneron shares dropped nearly 19% after the company’s experimental COPD drug, itepekimab, produced mixed late-stage trial results. One trial met its goal but the other did not, raising doubts about the drug’s commercial future.
**Date:** 2025-05-30
**Source:** [Proactive Investors](https://www.proactiveinvestors.com/companies/news/1072174/regeneron-shares-plunge-after-mixed-copd-drug-trial-results-1072174.html)
#### 2. [Jacobs & Co. CA Buys 859 Shares of Regeneron Pharmaceuticals, Inc. (NASDAQ:REGN)]
**Content:** Jacobs & Co. CA has increased its position in Regeneron by 9.3% in Q1 2025, alongside other notable institutional activity reflecting continued investor interest in the company.
**Date:** 2025-05-30
**Source:** [MarketBeat](https://www.marketbeat.com/instant-alerts/filing-jacobs-co-ca-buys-859-shares-of-regeneron-pharmaceuticals-inc-nasdaqregn-2025-05-29/)
#### 3. [Regeneron stock crashes on COPD data: here’s why I’m buying REGN today]
**Content:** Discusses the recent plunge in Regeneron’s share price due to the disappointing COPD trial data and presents a bullish case for longer-term investors.
**Date:** 2025-05-30
**Source:** [Invezz](https://invezz.com/news/2025/05/30/regeneron-stock-crashes-on-copd-data-heres-why-im-buying-regn-today/)
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**Summary:**
The most important recent news for Regeneron (REGN) is the sharp stock decline following weak Phase 3 results for its much-anticipated COPD medication, casting uncertainty on a major growth prospect. Institutional investors are still showing interest in REGN even as analysts and the market digest the latest clinical data setback[2][1].