Biosimilar Showdown: Sandoz’s Antitrust Challenge to Amgen Sparks Market Ripples

Switzerland’s Sandoz, part of the Novartis Group, has launched a high-stakes antitrust lawsuit against Amgen, accusing the biotech giant of unlawfully maintaining its dominance over the $3.3 billion-a-year U.S. market for Enbrel® (etanercept), a leading biologic treatment for autoimmune diseases. The case, filed in April 2025 in Virginia’s federal court, raises critical questions about how patent strategies intersect with antitrust laws in the pharmaceutical industry—and could reshape the economics of biosimilars in the U.S.

The Legal Battle: Patents vs. Competition

Sandoz alleges that Amgen acquired and enforced patents to block its biosimilar Erelzi® from entering the U.S. market, despite the FDA approving it in 2016. The lawsuit claims these tactics violate the Clayton Act by suppressing competition, denying cost-effective treatment to millions of patients. Erelzi® has been available in Europe since 2016, but Sandoz argues that Amgen’s “patent thicket” strategy has delayed its U.S. launch, perpetuating high prices.

Amgen, however, is likely to defend its patent rights as legitimate protections for its decades-old drug. Enbrel® was first approved in 1998, and its patents have been extended through secondary innovations—a common practice in the biologics industry. The court will need to balance Amgen’s right to patent-protected profits against Sandoz’s claims that these extensions stifle competition and patient access.

Market Implications: A Tipping Point for Biosimilars?

The outcome of this case could have far-reaching consequences. Enbrel®’s U.S. sales totaled $3.3 billion in 2024, a critical revenue stream for Amgen as it pivots to newer therapies like Otezla and Repatha. If Sandoz prevails, Erelzi® could immediately enter the market, slashing Enbrel®’s sales by as much as 30–40% within two years, according to industry analysts. This would pressure Amgen’s margins and send ripples through its pipeline-dependent valuation.

For Sandoz, success would validate its strategy of challenging patent thickets, potentially opening doors for other biosimilars in the U.S. market, where competition lags behind Europe. The broader biosimilar sector—including players like Mylan and Coherus—could also benefit if courts interpret the Clayton Act more aggressively against patent misuse.

Investment Considerations: Risks and Opportunities

Investors in Amgen (AMGN) face near-term uncertainty. The stock has already dipped 5% since the lawsuit was announced, reflecting concerns about prolonged legal costs and revenue erosion. However, Amgen’s robust pipeline and diversified portfolio—driven by oncology drugs like Blincyto and cardiovascular treatments—might mitigate long-term damage.

Sandoz’s parent company, Novartis (NVS), could see a boost if the case sets a precedent favoring biosimilar entrants. Novartis’s generic and biosimilar division has struggled with pricing pressures, but a favorable ruling might accelerate its growth trajectory.

Conclusion: A Crossroads for Innovation and Access

Sandoz’s lawsuit is not just about one drug—it’s a test of whether U.S. antitrust law can curb practices that shield monopolies in high-cost pharmaceutical markets. With 7.5 million Americans relying on Enbrel®, the case highlights the tension between patent incentives for innovation and the societal need for affordable medicines.

If Sandoz wins, biosimilars could finally gain traction in the U.S., pressuring entrenched biologics and reshaping pricing dynamics. Amgen’s fate will hinge on how courts interpret its patent strategy, but the broader industry will watch closely. For investors, the stakes are clear: the ruling could either unlock value for biosimilar manufacturers or reinforce the high barriers to competition that have long favored brand-name drugmakers.

As the trial unfolds, the $3.3 billion Enbrel® franchise remains a battleground where legal, financial, and ethical imperatives collide. The outcome may redefine the balance of power in one of healthcare’s most lucrative—and contentious—markets.