Regeneron and Sanofi Announce Dupixent Outperformance over Xolair in Phase 4 EVEREST Trial Results for CRSwNP and Asthma

Regeneron and Sanofi announced positive Phase 4 trial results for Dupixent, demonstrating its superiority over Xolair in treating adults with severe chronic rhinosinusitis with nasal polyps (CRSwNP) and co-existing asthma. The EVEREST trial showed Dupixent significantly improved nasal polyp size, sense of smell, lung function, and asthma control as early as four weeks, with similar safety profiles observed between the two medications. These findings, presented at the 2025 EAACI Congress, suggest Dupixent's potential to become a preferred treatment option for type 2 inflammation-associated conditions, though ongoing regulatory obligations and potential liabilities remain a factor.

Analysis

Regeneron (REGN) and Sanofi (SNY) announced compelling Phase 4 EVEREST trial results where Dupixent surpassed Xolair in treating adults with severe chronic rhinosinusitis with nasal polyps (CRSwNP) and co-existing asthma across all primary and key secondary endpoints. Dupixent demonstrated a statistically significant 1.60-point superior reduction in nasal polyp size and an 8.0-point superior improvement in smell identification (both p<0.0001), alongside a 150 mL greater improvement in lung function (pre-bronchodilator FEV1, p=0.003) and a 0.48-point better asthma control score (ACQ-7, p<0.0001) at 24 weeks, with benefits evident as early as four weeks. These findings, presented at the 2025 EAACI Congress, bolster Dupixent's role in managing type 2 inflammation and are poised to influence clinical practice. Safety profiles were broadly similar, with overall adverse events at 64% for Dupixent and 67% for Xolair; importantly, serious adverse events were lower for Dupixent (2%) versus Xolair (4%). Despite these positive clinical data and unanimous buy/overweight ratings from four recent analyst reports for REGN (median price target $802.5), institutional holdings data for REGN in Q1 2025 indicated more funds decreasing (771) than increasing (648) positions. This included substantial reductions by JPMORGAN CHASE & CO (-1,401,174 shares, an estimated $888.7 million) and CAPITAL WORLD INVESTORS (-840,346 shares, an estimated $533.0 million), although notable new or increased stakes were taken by firms like TWO SIGMA ADVISERS, LP (+553,800 shares, an estimated $351.2 million). Additionally, congressional trading in REGN over the past six months shows a predominance of sales (8 sales transactions versus 2 purchase transactions). Forward-looking statements from the company also caution about ongoing regulatory obligations and potential future liabilities, introducing an element of uncertainty to the commercial outlook.

Key Decisions for Investors

• The superior efficacy of Dupixent over Xolair, coupled with a favorable serious adverse event profile from the EVEREST trial, significantly strengthens its market position and revenue growth prospects for Regeneron and Sanofi, potentially supporting upward revisions to peak sales estimates.
• Investors should weigh the strong clinical trial outcomes and bullish analyst consensus for REGN against the observed net institutional outflows in Q1 2025 and net selling by members of Congress, which could indicate valuation concerns or profit-taking by some market participants requiring further due diligence.
• Consider the disclosed forward-looking risks, including ongoing regulatory scrutiny and potential liabilities, as material factors that may impact long-term commercial success and stock performance, notwithstanding the current positive clinical momentum.