Regeneron (REGN) Stock Plummets 11% Following Late-Stage Melanoma Trial Disappointment

Key Highlights

• Fianlimab, Regeneron’s investigational melanoma treatment, missed its primary progression-free survival goal in Phase 3 testing versus Merck’s Keytruda.
• The experimental therapy combined with Libtayo failed to demonstrate statistically meaningful advantages in delaying disease progression.
• Shares of REGN tumbled 11% to $618 during premarket hours following the trial readout.
• Wall Street responded with widespread downgrades; Citi moved to Neutral from Buy and reduced its price objective to $700 from $900.
• RBC Capital Markets decreased its target to $707, citing this setback as indicative of recent development challenges across the pipeline.

Shares of Regeneron Pharmaceuticals experienced significant premarket declines Monday after the biotechnology company disclosed that its investigational melanoma therapy fianlimab did not achieve its primary efficacy measure in advanced-stage clinical testing.

Regeneron Pharmaceuticals, Inc., REGN

The biotech’s shares retreated 11% to $618 before the opening bell. The selloff followed a late Friday disclosure regarding Phase 3 study outcomes.

The clinical trial evaluated fianlimab, an immunotherapy candidate targeting advanced melanoma, when administered alongside the company’s marketed drug Libtayo. This regimen was benchmarked against Merck’s blockbuster oncology treatment Keytruda, which generates billions in annual revenue.

Researchers enrolled 1,546 melanoma patients distributed among four treatment arms — a high-dose combination regimen, a low-dose combination approach, Keytruda administered with placebo, and Libtayo paired with placebo.

The investigational agent failed to deliver statistically significant benefits in progression-free survival. Put simply, patients receiving fianlimab did not experience meaningfully extended periods before their cancer worsened or death occurred when compared to those on Keytruda.

While the higher-dose fianlimab-Libtayo regimen demonstrated numerical advantages versus Keytruda, these improvements fell short of achieving statistical significance — the threshold required for regulatory and clinical credibility.

The disappointing trial results triggered immediate responses from Wall Street, with multiple analysts revising their outlooks downward.

Analyst Community Responds

Geoff Meacham from Citi Research downgraded his stance on Regeneron from Buy to Neutral and dramatically reduced his price objective to $700 from $900. His rationale centered on the absence of fianlimab from future projections, eliminating what he viewed as potential “incremental positive catalysts” supporting higher valuations.

Jefferies analyst Akash Tewari characterized the trial failure as “not particularly” unexpected, describing it as confirmation of bearish investor concerns. Despite maintaining his Buy recommendation, he lowered his target to $870 from $890 and eliminated fianlimab from his financial projections.

RBC Capital Markets adjusted its price objective downward to $707 from $762 while maintaining a Sector Perform designation. The firm had previously estimated probability-weighted peak revenue potential of $1.6–$1.8 billion for fianlimab in melanoma — projections now completely erased.

Broader Development Challenges Emerge

RBC highlighted that the fianlimab disappointment represents part of a concerning trend for Regeneron. The investment firm referenced additional recent obstacles including an unsuccessful itepekimab study, a more restrictive approved indication for Eylea HD, and production complications.

Sales of Regeneron’s Eylea franchise declined 10% during the first quarter, contributing to earlier stock pressure this year. Truist Securities reduced its target to $769 amid regulatory postponements, though analysts there preserved their Buy rating based on better-than-anticipated Q1 financial performance.

Not every analyst has adopted a pessimistic stance. BofA Securities maintained its Buy rating with an $860 target despite the clinical setback. Jefferies similarly upheld its positive recommendation.

On a more encouraging note, Dupixent — jointly developed with Sanofi — continues delivering robust growth through expansion into additional therapeutic areas and surpassing revenue forecasts. Eylea HD is reportedly regaining momentum, and Regeneron’s balance sheet maintains a net cash position.

According to InvestingPro metrics, thirteen analysts have lowered their earnings projections for the company’s next reporting period.

The post Regeneron (REGN) Stock Plummets 11% Following Late-Stage Melanoma Trial Disappointment appeared first on Blockonomi.