Amgen Stock Rises on Landmark Repatha Trial Results, But Biosimilar Pressures Keep Volume at 103rd in U.S. Rankings

Market Snapshot

On November 18, 2025, Amgen (AMGN) recorded a trading volume of $1.02 billion, ranking 103rd in U.S. equity trading activity. The stock closed the session with a 0.67% gain, reflecting modest positive momentum amid broader market conditions. This performance aligns with recent investor sentiment driven by clinical trial results and earnings guidance, though the volume level suggests mixed participation compared to the top-tier high-volume stocks.

Key Drivers Behind the Move

Amgen’s recent 0.67% price increase coincided with the release of detailed results from its Phase 3 VESALIUS-CV clinical trial for Repatha (evolocumab), a PCSK9 inhibitor. The trial demonstrated statistically significant and clinically meaningful reductions in major adverse cardiovascular events (MACE) among high-risk adults without prior heart attacks or strokes. This marks the first large-scale trial to show LDL-C-lowering therapy benefits in this demographic, expanding Repatha’s potential patient base. The findings, presented at the 2025 American Heart Association Scientific Sessions and published in the New England Journal of Medicine, reinforce Repatha’s role in primary prevention—a critical differentiator in a competitive lipid-lowering market.

The trial’s success has bolstered Amgen’s near-term revenue growth narrative. With Repatha now approved for adults at elevated risk of MACE linked to uncontrolled LDL-C, the company anticipates broader market adoption. This aligns with the FDA’s recent expansion of Repatha’s indication and Amgen’s direct-to-patient platform, AmgenNow, which offers the drug at a reduced price. Analysts have highlighted the potential for incremental revenue if Repatha gains traction in primary prevention, though this depends on physician adoption and payer reimbursement dynamics. The earnings guidance released on November 4, 2025, further underscores this potential, projecting $37.4 billion in revenue and $8.2 billion in earnings by 2028.

However, the investment case remains balanced against persistent challenges. Biosimilar competition and pricing pressures continue to weigh on Amgen’s core products, including Enbrel and Neulasta. The VESALIUS-CV results mitigate some of these risks by diversifying revenue streams, but analysts project a range of outcomes. Optimistic forecasts, such as a $318.51 fair value (7% downside to the current price), assume sustained Repatha growth and manageable biosimilar erosion. In contrast, more cautious estimates project revenue declines to $34.4 billion and earnings drops to $5.2 billion by 2028, reflecting aggressive pricing reforms and biosimilar penetration.

The trial also highlights Amgen’s R&D execution and pipeline resilience. As a fully human monoclonal antibody, Repatha’s mechanism offers durable competitive advantages in a sector increasingly focused on personalized and preventative therapies. Jay Bradner, Amgen’s executive vice president of R&D, emphasized the trial’s validation of LDL-C lowering as a critical cardiovascular risk reduction strategy. This aligns with broader industry trends toward precision medicine and proactive disease management, positioning Amgen to capitalize on long-term market shifts.

Despite these positives, short-term volatility remains a risk. The stock’s 0.67% gain contrasts with the 5.6% surge reported in some coverage, suggesting mixed investor interpretation of the data. This discrepancy may stem from differing valuations of Repatha’s market potential versus near-term execution risks. For example, while the trial expands Repatha’s indication, its high cost and the availability of cheaper alternatives (e.g., generic statins) could limit uptake. Additionally, Amgen’s broader portfolio faces patent expirations and biosimilar launches, which could offset Repatha’s gains unless offset by robust R&D innovation.

In conclusion, Amgen’s stock performance reflects a pivotal moment in its strategic evolution. The VESALIUS-CV results strengthen its cardiovascular franchise and reinforce a growth narrative centered on Repatha’s expanded role in primary prevention. However, sustained success will depend on navigating pricing pressures, biosimilar competition, and R&D execution risks. Investors appear cautiously optimistic, as evidenced by the stock’s modest gain and the divergence in analyst forecasts. The coming quarters will be critical in determining whether Amgen can translate these clinical milestones into durable financial growth.