Biosimilar Patent Infringement Cases in 2025 Amid a Looming Patent Cliff

Introduction: A Wave of Biosimilar Challenges and the "Patent Cliff"

The biopharmaceutical industry is witnessing a surge of patent infringement battles over biosimilars in 2025. A major reason is the "patent cliff" -- a wave of blockbuster biologic drugs losing patent protection around this time. As patents and exclusivities expire, biosimilar manufacturers are rushing to introduce lower-cost versions, while innovator companies file lawsuits to defend their franchises.

By 2030, nearly 69 biologic medicines (worth over $230 billion in annual sales) are expected to lose exclusivity. This second wave of biologic patent expirations (the first wave in 2010–2020 included drugs like infliximab and trastuzumab) is opening unprecedented competition.

In this context, 2025 has seen multiple high-profile biosimilar patent infringement cases worldwide. Originator firms often rely on extensive patent portfolios -- sometimes dubbed "patent thickets" -- covering not just the drug's composition but also formulations, manufacturing methods, and uses.

These overlapping patents can delay competitors even after the core patent expires, especially in the United States where BPCIA litigation (under the Biologics Price Competition and Innovation Act) is a key battleground. Below, we examine notable 2025 cases across different geographies and discuss how the looming patent cliff is driving these disputes.

Roche vs. Biosimilar Pertuzumab (Perjeta) -- US and India Battles

One prominent 2025 case involves Roche's blockbuster cancer antibody Perjeta® (pertuzumab). On August 14, 2025, Genentech (Roche's subsidiary) filed the first U.S. patent infringement lawsuit targeting a pertuzumab biosimilar. The complaint, filed in the U.S. District of New Jersey, accuses Shanghai Henlius Biotech and its partner Organon of infringing 24 U.S. patents related to Perjeta. These patents cover the pertuzumab molecule, pharmaceutical compositions, treatment methods, and antibody manufacturing processes.

The trigger was Henlius's FDA application for HLX11, a proposed pertuzumab biosimilar accepted in January 2025. Genentech is seeking judgments of infringement, injunctions to block HLX11's launch, and damages. This marks the first pertuzumab biosimilar lawsuit and follows a familiar pattern seen with earlier biologics like adalimumab and etanercept, where patent suits delayed competitors and prolonged the brand's monopoly.

Roche's defensive strategy is global. Just weeks before the U.S. suit, Roche publicly acknowledged that biosimilar competition to Perjeta was "closer than previously anticipated," a shift from a few months earlier when it downplayed the threat from Henlius. In India, Roche is also taking action to protect Perjeta: it filed a case against Zydus Lifesciences to block "Sigrima®," Zydus's pertuzumab biosimilar. The High Court of Delhi granted an interlocutory order in July 2025, restraining Zydus from certain activities pending trial.

These moves show Roche's determination to fend off pertuzumab biosimilars on multiple fronts as Perjeta's patents approach expiry in 2025. Notably, Henlius's HLX11 is also under review in Europe (as of March 2025), so similar patent maneuvers could play out there under country-specific or EU Unified Patent Court proceedings.

Significance: Pertuzumab (launched 2012) is a key HER2-positive breast cancer therapy with 2024 sales of ~$4.3 billion. Its patent cliff in 2025 means several biosimilar makers (Henlius, Zydus, and likely others) are poised to enter. Roche's infringement suits aim to delay those entrants. The 24 patents asserted indicate Roche's heavy patent estate on Perjeta, a common tactic to shield biologics near the end of their exclusivity. The outcome of these cases will determine how soon cheaper pertuzumab options reach patients in the US, India, and beyond.

Amgen's Denosumab (Prolia/Xgeva) Litigation Blitz in 2024–2025

Another dramatic example is Amgen's campaign to protect denosumab, the antibody behind osteoporosis drug Prolia® and cancer bone therapy Xgeva®. Denosumab's primary patents began expiring around 2024–2025, and a host of companies have developed biosimilars. Amgen responded with a flurry of BPCIA lawsuits in the U.S., asserting a formidable patent thicket. By mid-2025, Amgen had five to seven patent cases pending against proposed denosumab biosimilars. This includes suits filed in late 2024 and 2025 against:

• Accord BioPharma/Intas -- BLA for "INTP23"
• Samsung Bioepis -- BLA for "Ospomyv™/Xbryk™ (denosumab-dssb)"
• Hikma Pharmaceuticals/Gedeon Richter -- BLA for "RGB-14"
• Shanghai Henlius/Organon -- BLA for "HLX14"
• Biocon Biologics -- BLA for "Bmab 1000"
• (Earlier, in 2023–24, Amgen also sued Sandoz, Celltrion, and Fresenius Kabi for their denosumab programs.)

In late June 2025 alone, Amgen filed three new lawsuits: on June 25, 2025, two cases in New Jersey federal court against Hikma/Richter and Henlius/Organon, and on June 30 a case in Massachusetts against Biocon. Across these, Amgen claims infringement of over 30 patents per case, covering everything from the denosumab amino-acid sequence to formulation, cell cultures, and manufacturing methods.

In total, 51 distinct patents have been asserted against Prolia/Xgeva biosimilars as of mid-2025 – a striking illustration of the patent thicket concept (most are method-of-production and formulation patents rather than the original composition-of-matter).

Despite the aggressive litigation, Amgen has also been settling many disputes to schedule competitor launches. In the 18 months prior to mid-2025, at least three cases resolved via settlement or court order:

• A suit with Sandoz (filed May 2023) was settled in April 2024, granting Sandoz a license to launch its denosumab biosimilars (branded Jubbonti® and Wyost®) in the U.S. starting May 31, 2025. Sandoz did launch those products in early June 2025 as the first U.S. Prolia/Xgeva biosimilars.
• Amgen settled with Celltrion in January 2025, permitting Celltrion's product (CT-P41) to launch in the U.S. from June 1, 2025 (though Celltrion had not launched as of mid-2025).
• In March 2025, Amgen reached a global settlement with Fresenius Kabi, allowing Fresenius's denosumab biosimilar to launch in mid-2025. (Global terms suggest the deal covered not only U.S. patents but other jurisdictions as well.)

As of mid-2025, ongoing U.S. cases include those against Samsung Bioepis and Accord/Intas, consolidated as multidistrict litigation, plus the newly filed suits against Henlius, Hikma, and Biocon. These cases will determine the staggered entry of remaining denosumab biosimilars. Amgen's strategy – suing widely but then licensing launches a few years out – mirrors the approach AbbVie took with Humira®. It delays full-on competition while avoiding the uncertainty of trial outcomes.

Indeed, the first denosumab biosimilar launched in 2025 (Sandoz's) came only after Amgen secured an extra two-year window post patent-expiry via settlement.

Significance

Denosumab exemplifies how the 2025 patent cliff drives litigation. Prolia/Xgeva together generated over $4.4 billion in U.S. sales in 2024, so multiple manufacturers (Sandoz, Celltrion, Biocon, Pfizer's Hospira, etc.) invested in biosimilars. Amgen's 34+ asserted patents (many on manufacturing) show how originators try to extend protection beyond the original 20-year patent term.

However, the wave of settlements also indicates that biosimilars will arrive soon after the cliff: Amgen has effectively scheduled a sequence of entrants through 2025–2026. This balance -- litigation followed by licensing -- is becoming common as big biologics lose exclusivity. It allows some competition (benefiting patients with lower prices) while giving the innovator a bit more exclusivity in exchange for avoiding litigation risk.

Other Notable Biosimilar Patent Cases and Developments in 2025

Ustekinumab (Stelara®)

Janssen's immunology drug (for psoriasis, IBD, etc.) faced biosimilar challenges as its U.S. exclusivity ended in 2023. While the key patent fights occurred earlier, 2025 is the year multiple Stelara biosimilars actually launched. For example, Accord/Intas launched Imuldosa™ (ustekinumab-srlf) in 2025 after FDA approval. Janssen had sued players like Amgen and Alvotech in 2022, but those cases were settled with licenses granting them staggered entry (Amgen's Stelara biosimilar launched in July 2023 in EU and January 2025 in the US under a settlement deal).

This reflects the pattern of litigation leading to delayed – but not denied – biosimilar launches, as noted by analysts. By 2025, the Stelara biosimilar market is underway due to those resolved patent disputes.

Etanercept (Enbrel®)

A cautionary tale in contrast to Stelara. Biosimilars for Enbrel have been available in Europe for years (its EU patents lapsed in 2015), but in the U.S., Amgen's patents (filed later) have blocked biosimilars until 2029. Sandoz's attempt to invalidate Amgen's Enbrel patents failed in court, resulting in no U.S. biosimilar launch despite a FDA-approved product.

The Enbrel situation underscores how a strong patent estate can prolong a monopoly long past the original patent's life, delaying competition for nearly a decade. It also highlights why biosimilar firms target expiry dates aggressively -- if they don't challenge patents, they may be kept out for years.

Omalizumab (Xolair®)

This antibody for asthma and hives (co-marketed by Roche/Genentech and Novartis) illustrates a 2025 patent cliff where litigation was minimal but timing is critical. Xolair's U.S. patents (including a formulation patent) expire in November 2025. Celltrion obtained FDA approval in March 2025 for Omlizumab-igec (Omlyclo™), the first Xolair biosimilar. However, due to remaining patent protection, Celltrion will delay launch until late 2026. Roche has even stated it expects no U.S. Xolair biosimilar competition in 2025.

This suggests that rather than litigate, the biosimilar sponsor opted to wait for patent expiry (possibly via an agreement or simply by choice). In other words, the patent cliff itself (late 2025) is determining market entry. Europe's situation is similar: Xolair biosimilars have been approved (e.g. by Sandoz in 2023), but full rollout awaits patent lapse. This case shows that not every patent cliff results in a courtroom battle – sometimes the timing of expiry and regulatory approval naturally staggers the competition.

Soliris® (eculizumab)

A monoclonal antibody for rare diseases, Soliris patents also expired around 2024–2025 globally. Biosimilars emerged (e.g. in 2022–2023 in Europe and Japan), and in 2025 AstraZeneca's Alexion unit (the brand owner) braced for U.S. competition. We saw legal positioning here too: Alexion previously filed patent suits and also transitioned patients to a successor product (Ultomiris) to blunt biosimilar impact. By 2025, at least one Soliris biosimilar was under FDA review, and AstraZeneca noted it "faces biosimilar challenge this year".

While specific 2025 U.S. lawsuits for Soliris aren't public, the company likely engaged in patent settlements or opposition proceedings to manage biosimilar entry. This reflects how originators often prepare two prongs of defense at patent cliffs: litigation and lifecycle management (new formulations or next-gen drugs).

Small-Molecule Note

The 2025 patent cliff also includes traditional drugs (small molecules) like Novartis's Entresto® (heart failure drug, LOE July 2025) and AstraZeneca's Farxiga® (diabetes, LOE 2025). These saw Hatch-Waxman generic lawsuits rather than BPCIA cases, but they underscore the broader patent cliff pressure. For instance, generic challengers for Entresto triggered litigation and by late 2024 a U.S. court invalidated a Novartis patent, allowing generics upon exclusivity end. Similarly, Bristol Myers Squibb fought off Eliquis generics until 2026 via court wins. While these are not biosimilar cases, they run parallel to the biologics battles, all contributing to 2025's status as a "pivot year" for patent expirations.

Outlook: Trends Amid the Patent Cliff

2025's cluster of biosimilar patent cases is a bellwether for how the pharma landscape will evolve under the patent cliff. Innovator companies continue to deploy expansive patent portfolios and legal actions worldwide (U.S. federal courts, India's High Courts, European national courts, etc.) to squeeze out a few more months or years of exclusivity. These tactics -- including patent thickets and "evergreening" strategies -- have historically slowed U.S. biosimilar uptake. Indeed, the first decade of U.S. biosimilars (2010–2020) saw only a trickle of approvals partly due to protracted patent litigation.

However, the current wave of expirations is inevitably eroding those monopolies. Many 2025 lawsuits are concluding with settlements that fix a launch date rather than block the biosimilar indefinitely. This trend suggests that, while patent litigation might delay biosimilars, it typically results in negotiated entry rather than absolute prevention. In fact, a recent industry analysis noted that patent settlements often accelerate patient access compared to fighting to the bitter end. For example, AbbVie's global settlements allowed Humira biosimilars in Europe by 2018 and in the U.S. by 2023, sooner than if every patent was litigated to expiry.

Another factor tempering the impact of patent stalling tactics is the push from regulators and payers. In Europe, healthcare systems have embraced biosimilars rapidly to cut costs, and even the U.S. is seeing quicker adoption and interchangeability designations that make substitution easier. By 2030, biosimilars are expected to be a mainstream part of healthcare, with dozens more biologics (e.g. Keytruda®, Opdivo®, Darzalex®) losing exclusivity in the next few years. The "golden era" of biosimilars is arriving, bringing more affordable therapies but also intense legal jockeying as seen in 2025.

In summary, 2025 has been a pivotal year for biosimilar patent infringement cases globally. From Roche's multi-continent defense of Perjeta, to Amgen's patent gauntlet around Prolia/Xgeva, and numerous settlements enabling new biosimilars like ustekinumab to launch -- the activity is fierce. This is all set against the backdrop of a patent cliff of tectonic magnitude, with tens of blockbuster drugs reaching the end of their protected life. We can expect the pattern to continue: big pharma will litigate and negotiate to protect their assets, while biosimilar companies will increasingly prevail as the last key patents expire. Ultimately, despite legal delays, a greater number of biosimilars will reach patients, ushering in more competition and potentially significant healthcare savings as the patent cliff reshapes the market.