Biologics and Biosimilars Landscape 2025: IP, Policy, and Market Developments

In Fish & Richardson’s 2025 biologics and biosimilars review, we cover Food and Drug Administration (FDA) approvals, new biosimilar launches, Biologics Price Competition and Innovation Act (BPCIA) litigation and other litigation implicating biologics, post-grant challenges against biologic patents, and biologics-related legislative and regulatory developments from 2025.

I. Biosimilar approvals, launches, and pipeline

The U.S. biosimilars market continued its rapid growth in 2025. In 2025, FDA approved 18 biosimilars referencing ten molecules across six therapeutic areas, reflecting continued diversification beyond oncology and inflammatory indications which were more prevalent for earlier-generation biosimilars. Notably, approvals from 2025 were concentrated in four main areas: (a) denosumab, which saw a large wave of biosimilar approvals; (b) ophthalmology (aflibercept and ranibizumab); (c) immunology (ustekinumab, tocilizumab, and omalizumab); and (d) diabetes (insulin aspart).

Therapeutic Area	Molecule	Reference Product	Biosimilar	Approval Date
Ophthalmology	Aflibercept	Eylea® (Regeneron)	Eydenzelt® (Celltrion)	Oct. 2025
Ophthalmology	Ranibizumab	Lucentis® (Roche / Genentech)	Nufymco® (Formycon / Bioeq)	Dec. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	OspomyvTM and XbrykTM (Samsung Bioepis)	Feb. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	Osenvelt® and Stoboclo® (Celltrion)	Feb. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	Bomyntra® and Conexxence® (Fresenius Kabi)	Mar. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	Bildyos® and Bilprevda® (Henlius)	Aug. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	BosayaTM and AukelsoTM (Biocon)	Sep. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	EnobyTM and XtrenboTM (Hikma)	Sep. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	Osvyrti® and Jubereq® (Accord)	Oct. 2025
Bone health	Denosumab	Prolia® and Xgeva® (Amgen)	BoncresaTM and OziltusTM (Amneal / mAbxience)	Dec. 2025
Oncology	Bevacizumab	Avastin® (Genentech)	JobevneTM (Biocon)	Apr. 2025
Oncology	Pertuzumab	Perjeta® (Genentech)	Poherdy® (Henlius)	Nov. 2025
Diabetes	Insulin aspart	Novolog® (Novo Nordisk)	MerilogTM (Sanofi)	Feb. 2025
Diabetes	Insulin aspart	Novolog® (Novo Nordisk)	KirstyTM (Biocon)	Jul. 2025
Immunology	Tocilizumab	Actemra® (Genentech)	Avtozma® (Celltrion)	Jan. 2025
Immunology	Ustekinumab	Stelara® (Janssen)	StarjemzaTM (Bio-Thera / Hikma)	May 2025
Immunology	Omalizumab	Xolair® (Genentech)	Omlyclo® (Celltrion)	Mar. 2025
Supportive care	Pegfilgrastim	Neulasta® (Amgen)	ArmlupegTM (Lupin / Valorum)	Nov. 2025

Table 1. Biosimilar BLAs approved in 2025

Several approvals were notable as first-in-kind and/or interchangeability designations. Poherdy^®, referencing Perjeta®, was the first interchangeable pertuzumab biosimilar approved for the treatment of HER2-positive breast cancer in combination with trastuzumab and additional chemotherapies. Omlyclo^®, referencing Xolair^®, was the first interchangeable omalizumab biosimilar approved for the treatment of moderate to severe persistent allergic forms of asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), chronic spontaneous urticaria (CSU), and IgE-mediated food allergy.

2025 also saw one of the highest annual totals of interchangeable designations to date, with FDA designating more than 20 biosimilars as interchangeable, up from nine interchangeables in 2024. This trend appears consistent with FDA’s broader efforts to lower regulatory barriers to interchangeability. In June 2024, FDA issued draft guidance indicating that routine switching studies, which were generally recommended in the past, would largely not be necessary. Additional FDA draft guidance from October 2025, discussed below, proposed further updates aimed at reducing unnecessary clinical testing in biosimilar development.

There were also 16 new U.S. biosimilar product launches in 2025. Eight launched products referenced Stelara^® (ustekinumab), reflecting the coordinated market entry that followed settlements between biosimilars and Johnson & Johnson. Four launched products referenced Prolia^® and Xgeva^® (denosumab), marking the beginning of what is expected to be a highly competitive market in bone health. Two launched products referenced Soliris^® (eculizumab), and additional launches included Celltrion’s Avtozma^® (tocilizumab) and Sandoz’s Tyruko^® (natalizumab). Notably, Sandoz launched Tyruko^® “at risk,” with litigation against Biogen pending in the District of Delaware, as discussed below.

Figure 1. Annual biosimilar approvals, interchangeability designations, and launches 

U.S. biosimilar development activity remained strong in 2025. FDA has reported that, as of December 2025, 135 biosimilar development programs were enrolled in its Biosimilar Biological Product Development (BPD) program, reflecting continued engagement between FDA and biosimilar developers. Participation in FDA’s BPD program reflects a biosimilar developer’s formal engagement with FDA regarding development of a proposed biosimilar, though not all BPD programs result in a submitted or approved Biologics License Application (BLA). Because biosimilar developers typically participate in the BPD program before filing, BPD enrollment trends remain an indicator, but not a guarantee, of future biosimilar filings and approvals. Table 2 lists some of the biosimilars currently pending FDA approval based on publicly available information as of publication:

Therapeutic Category	Reference Product	Proposed Biosimilar	FDA Status
Asthma	Xolair® (omalizumab)	ADL-018 (Amneal / Kashiv)	BLA Submitted: Sep. 2025
Ophthalmology	Eylea® (aflibercept)	AVT06 (Alvotech / Teva)	CRL Issued: Feb. 2025
Ophthalmology	Eylea® (aflibercept)	SCD-411 (Fresenius / SCD)	BLA Accepted: Dec. 2025
Ophthalmology	Lucentis® (ranibizumab)	Lucamzi (Stada / Valorum)	CRL Issued: Oct. 2025
Bone health	Prolia® and Xgeva® (denosumab)	MB09 (mAbxience / Amneal)	BLA Accepted: Mar. 2025
Bone health	Prolia® and Xgeva® (denosumab)	ENZ215 (Enzene/Alkem)	BLA Accepted: Undisclosed Date
Bone health	Prolia® and Xgeva® (denosumab)	AVT03 (Alvotech / Dr. Reddy’s Labs.)	CRL Issued: Dec. 2025
Bone health	Prolia® and Xgeva® (denosumab)	TVB-009P (Teva)	CRL Issued: Jul. 2025
Diabetes	Lantus® (insulin glargine)	Basalin (Gan & Lee / Sandoz)	BLA Accepted: Feb. 2023
Diabetes	NovoLog® (insulin aspart)	AMP-004 (Amphastar)	BLA Accepted: Apr. 2025
Diabetes	Humalog® (insulin lispro)	Prandilin (Gan & Lee / Sandoz)	CRL Issued: Mar. 2024
Immunology	Simponi® (golimumab)	AVT05 (Alvotech / Teva)	CRL Issued: Nov. 2025
Immunology	Simponi® (golimumab)	BAT2506 (Bio-Thera)	BLA Accepted: Jul. 2025
Oncology	Herceptin® (trastuzumab)	TX05 (Tanvex)	CRL Issued: Jan. 2025
Oncology	Herceptin® (trastuzumab)	EG12014 (EirGenix / Sandoz)	BLA Resubmitted: Jun. 2025

Table 2. Exemplary pending biosimilar BLAs¹

The biosimilar approvals, launches, and ongoing development projects discussed above reflect a continued maturation of the U.S. biosimilars market.

II. BPCIA litigation 2025 update

BPCIA litigation activity in 2025 remained steady and highly concentrated on a small number of products. Eight new BPCIA complaints were filed: six involved Prolia^® and Xgeva^® (denosumab), one involved Eylea^® (aflibercept), and one involved Perjeta^® (pertuzumab).

Figure 2. BPCIA cases filed by year since BPCIA enactment

Denosumab remained the epicenter of BPCIA litigation activity. By the end of 2025, Amgen had filed 11 BPCIA suits against denosumab biosimilar developers, underscoring the concentration of biosimilar development activity in the denosumab market. Aflibercept litigation from previous years mostly slowed down following Federal Circuit decisions affirming preliminary injunctions against three biosimilar developers and denying a preliminary injunction against Amgen. Following those rulings, the enjoined aflibercept biosimilar makers entered settlement agreements with Regeneron providing licensed entry in mid-2026 to early-2027. As of this writing, only Amgen remains in litigation.

2025 also saw continued consolidation of complex, multi-defendant BPCIA cases through multidistrict litigation proceedings, including a new denosumab multidistrict litigation (MDL) in the District of New Jersey.

Lastly, across multiple cases, reference product sponsors increasingly allege deficiencies in patent advance disclosures under 42 U.S.C. § 262(l), particularly with respect to manufacturing information. 

A. PROLIA^® and XGEVA^® (denosumab) litigations

Our 2024 report discussed Amgen’s BPCIA cases related to denosumab biosimilars against Sandoz (Jubbonti^® and Wyost^®), Celltrion (Osenvelt^® and Stoboclo^®), Samsung Bioepis (Ospomyv™ and Xbryk™), Fresenius Kabi (Bomyntra^® and Conexxence^®), and Accord (Osvyrti^® and Jubereq^®). In February 2025, the Judicial Panel on Multidistrict Litigation consolidated all then-pending denosumab cases before Judge O’Hearn in the District of New Jersey for pretrial proceedings. In re: Denosumab Patent Litigation, No. 25-md-3138 (D.N.J.).

During 2025, Amgen filed six additional BPCIA complaints, bringing the total number of denosumab cases to 11. Specifically, Amgen brought suit against Biocon (Bosaya™ and Aukelso™), Hikma/Gedeon Richter (Enoby™ and Xtrenbo™), Henlius/Organon (Bildyos^® and Bilprevda^®), Alkem (ENZ215), Amneal (Boncresa™ and Oziltus™), and Dr. Reddy’s Laboratories (DRL)/Alvotech (AVT03). Across those cases, Amgen asserted between 26 and 34 patents generally directed to denosumab and related methods of manufacture. A recurring allegation in these complaints was Amgen’s assertion that biosimilar defendants failed to comply with 42 U.S.C. § 262(l)(2)(A) by purportedly withholding production of manufacturing information from their patent dance disclosures. Particularly noteworthy was the complaint against Alkem, where Amgen challenged Alkem’s provision of only “view-only” access to its BLA as failure to comply with the BLA’s requirement to provide “a copy” of the application.

By the end of 2025, Amgen reached settlements with several biosimilar developers, while litigations against others — Henlius/Organon, Alkem, Amneal, and DRL/Alvotech — remain pending.

Biosimilar	Case Status	Licensed Entry2	U.S. Launch
Jubbonti® and Wyost® (Sandoz)	Settled (Apr. 29, 2024)	May 31, 2025	June 2025
Stoboclo® and Osenvelt® (Celltrion)	Settled (Jan. 23, 2025)	June 1, 2025	July 2025
Conexxence® and Bomyntra® (Fresenius Kabi)	Settled (Mar. 7, 2025)	June 30, 2025	July 2025
Osvyrti® and Jubereq® (Accord)	Settled (July 16, 2025)	Oct. 1, 2025	N/A
Bosaya™ and Aukelso™ (Biocon)	Settled (Sep. 30, 2025)	Oct. 1, 2025	N/A
Enoby™ and Xtrenbo™ (Hikma / Gedeon Richter)	Settled (Nov. 24, 2025)	Jan. 1, 2026	N/A
Ospomyhv™ and Xbryk™ (Samsung Bioepis)	Settled (Sep. 5, 2025)	Confidential	N/A
Bildyos® and Bilprevda® (Henlius / Organon)	Pending	N/A	September 2025
ENZ215 (Alkem)	Pending	N/A	N/A
Boncresa™ and Oziltus™ (Amneal)	Pending	N/A	N/A
AVT03 (DRL / Alvotech)	Pending	N/A	N/A

Table 3. Denosumab BPCIA litigation overview

B. EYLEA^® (aflibercept) litigations

To date, Regeneron has brought nine BPCIA litigations against six aflibercept biosimilar developers: Celltrion (Eydenzelt^®), Samsung Bioepis (Opuviz™), Amgen (Pavblu^®), Biocon (Yesafili™), Formycon (Ahzantive^®), and Sandoz (Enzeevu™).

In 2025, the aflibercept MDL before Judge Kleeh in the Northern District of West Virginia, In re: Aflibercept Patent Litigation, No. 24-md-3103 (N.D. W.Va.), continued to see significant activity both at the district court and appellate court.

In early 2025, the Federal Circuit affirmed the preliminary injunctions against Samsung Bioepis, Formycon, and Celltrion, while affirming the denial of a preliminary injunction against Amgen. In its decisions affirming the preliminary injunctions, the Federal Circuit held that the district court had personal jurisdiction over foreign biosimilar makers Samsung Bioepis, Formycon, and Celltrion; the asserted formulation claims were not invalid for obviousness-type double patenting or for lack of written description; and there was a causal nexus between the alleged infringement and irreparable harm. The decision in the Amgen case turned on claim construction. The Federal Circuit held that the asserted claims, which separately recited a VEGF antagonist and a buffer, required the VEGF antagonist and the buffer to be separate and distinct components, and because Amgen’s product did not contain buffer separate from aflibercept (the VEGF antagonist), Regeneron did not establish a likelihood of success on the merits.

Formycon filed a motion with the district court to dissolve the preliminary injunctions against it in May 2025. The filings related to Formycon’s motion are largely under seal. Before the court resolved the motion, Regeneron reached settlement with Formycon on September 29, and shortly thereafter, with Celltrion on October 20. Biocon and Sandoz had previously settled with Regeneron on April 21 and September 9, respectively. Regeneron’s aflibercept BPCIA cases against Samsung Bioepis and Amgen continued into 2026.

Additionally, in January 2025 Samsung Bioepis filed its answer and counterclaims, alleging inequitable conduct as to five asserted patents. Dkt. 457. Regeneron moved to strike and to dismiss Samsung Bioepis’s inequitable conduct affirmative defense and counterclaim against a patent generally related to methods of treatment using aflibercept. Dkt. 472. In its response to Regeneron’s complaint, Samsung Bioepis alleged that by failing to identify certain press releases and Securities and Exchange Commission (SEC) filings during prosecution of two unasserted patents, Regeneron engaged in misconduct rendering the asserted method-of-treatment patent unenforceable due to infectious unenforceability. Dkt. 472 at 1–2. In September 2025, the court denied Regeneron’s motion, finding that factual questions regarding whether Regeneron successfully cured any inequitable conduct were unripe for disposition at the pleadings stage. Dkt. 669 at 4. Later, on February 12, 2026, Regeneron and Samsung Bioepis reached settlement.

Biosimilar	Case Status	Licensed Entry3	U.S. Launch
Pavblu® (Amgen)	Pending	N/A	Oct. 2024
Yesafili™ (Biocon/Mylan)	Settled (Apr. 2025)	2nd half of 2026	N/A
Eydenzelt® (Celltrion)	Settled (Oct. 2025)	Dec. 31, 2026	N/A
Enzeevu™ (Sandoz)	Settled (Sep. 2025)	Q4 2026	N/A
Ahzantive® (Formycon)	Settled (Sep. 2025)	Q4 2026	N/A
Opuviz™ (Samsung Bioepis)	Settled (Feb. 2026)	Jan. 2027	N/A

Table 4. Aflibercept BPCIA litigation overview

In June 2025, Regeneron filed a second BPCIA suit against Amgen asserting U.S. Patent No. 12,331,099 (the “’099 patent”), relating to bufferless aflibercept formulations, which Regeneron alleges reads on Amgen’s Pavblu^® product. No. 25-cv-5499 (C.D. Cal.). After the case was consolidated with the MDL in West Virginia, Amgen responded on September 12, asserting 14 affirmative defenses and eight counterclaims. Amgen’s counterclaims include allegations of inequitable conduct, prosecution latches, patent misuse, and unfair competition. Dkt. 644. In November 2025, Regeneron moved to strike Amgen’s affirmative defenses and to dismiss Amgen’s counterclaims for failure to state a claim. Dkt. 680. Briefing closed on Regeneron’s motion in February 2026. Dkt. 721. The motion remains pending.

C. PERJETA^® (pertuzumab) litigation

As we have previously reported, on August 14, 2025, Genentech and Hoffmann-La Roche (together, “Genentech”) filed the first and, to date, only BPCIA litigation concerning Perjeta^® (pertuzumab) against biosimilar company Shanghai Henlius Biotech and its development partner, Organon. Genentech, Inc. v. Shanghai Henlius Biotech, No. 25-cv-14648 (D.N.J.). The complaint alleges infringement of 24 patents by Henlius and Organon’s proposed pertuzumab biosimilar, Poherdy^® (then known as HLX11), including five patents that were previously asserted by Genentech in BPCIA litigation related to Herceptin^®, Actemra^®, Rituxan^®, and Avastin^®. Dkt. 1. The complaint also indicates that the parties had engaged in and completed the patent dance. While Genentech ultimately asserted 24 patents in its complaint, during the patent dance, it included 47 patents on its 3A List. Id. ¶ 56. Additionally, unlike in other recent BPCIA cases, Genentech’s complaint does not allege any deficiencies in Henlius and Organon’s patent dance disclosures. Henlius and Organon responded to the complaint on October 20, asserting counterclaims for declaratory judgments of invalidity and non-infringement, and Genentech filed its answer to Henlius and Organon’s counterclaims on November 10. The parties entered into a confidential settlement agreement and jointly dismissed the case at the end of January 2026. Dkt. 15.

D. TYSABRI^® (natalizumab) litigation

Originally filed in 2022, Biogen’s BPCIA suit against Sandoz and its development partner Polpharma concerning Tyruko^® (natalizumab) remains pending in the District of Delaware. Biogen Inc. v. Sandoz Inc., No. 1:22-cv-01190 (D. Del.). Biogen’s complaint originally alleged infringement of 28 patents. The court denied Biogen’s motion for a preliminary injunction in June 2023, holding that Biogen failed to prove it would suffer irreparable harm and that Biogen failed to demonstrate a likelihood of success on the merits. Dkt. 270 at 4. The court issued a claim construction order in July 2024, and fact discovery on most issues closed in September 2024. Dkt. 411.

In January 2025, Biogen narrowed its asserted patents down to five as required by the scheduling order. Since then, due to “limited and necessary” supplemental discovery related to assays used to detect a patient’s risk of developing a rare brain infection, the trial date has been rescheduled twice. Dkt. 639, 699.

On June 16, Sandoz and Polpharma filed a motion requesting a separate bench trial in August 2025 on their affirmative defenses and counterclaims of invalidity, license, patent exhaustion; equitable defenses; and counterclaims seeking declaratory judgment of unenforceability. Dkt. 707. The court denied the defendants’ motion on September 18. Dkt. 741.

On October 29, the parties agreed to dismiss all claims and defenses relating to three of the five asserted patents. Dkt. 753. The remaining patents, U.S. Patent Nos. 10,233,245 and 11,292,845, generally relate to methods of using natalizumab. On January 12, 2026, the court entered a stipulation and order dismissing Polpharma from the case. Dkt. 763.

A five-day jury trial is set to begin April 12, 2027.

III. Post-grant challenges to biologics at the PTAB

Biologic and biosimilar activity at the Patent Trial and Appeal Board (PTAB) in 2025 was up significantly compared to 2024, with 18 inter partes review (IPR) petitions and 13 PGR petitions filed, compared to 11 IPR petitions and four post-grant review (PGR) petitions filed in 2024.

IPR filings related to biologics overall have leveled out significantly since 2017’s record high of 87 IPR petitions filed (not shown). 2025 marks the first year that the number of PGR petitions filed has pulled close to level with the number of IPR petitions filed. However, 11 of the 13 PGRs filed related to Halozyme’s enzyme technology alleged to be used in the subcutaneous form of Merck’s Keytruda^® (pembrolizumab), discussed in more detail below. In general, 2025 saw a rise in petitions challenging patents directed to biologics-related manufacturing processes or otherwise nontraditional or biologic-adjacent-type patents, as opposed to patents claiming biologic compositions, formulations, or methods of use/treatment.

Figure 3. Biologic post-grant petitions filed by year

We discuss exemplary filings and developments briefly below.

A. Eylea^® (aflibercept) / Zaltrap^® (ziv-aflibercept)

We have previously detailed ongoing challenges to Regeneron’s patents related to aflibercept at the PTAB. To recap, eight of Regeneron’s patents were either found unpatentable by the PTAB or statutorily disclaimed by Regeneron. Six of these were method of treatment patents, one was a composition patent, and one related to manufacturing.

In November 2024, Samsung Bioepis brought a new challenge against the previously unchallenged U.S. Patent No. 11,084,865 (IPR2025-00176). As discussed above, the ’865 patent is the formulation patent that formed the basis of the permanent and preliminary injunction decisions in the Northern District of West Virginia. Formycon shortly followed with a follow-on petition and a motion for joinder (IPR2025-00233). Both Celltrion and Fresenius Kabi subsequently filed their own IPR petitions challenging the ’865 patent (IPR2025-00456 and IPR2025-01268, respectively). All four petitions were discretionarily denied by the PTAB, with then-Acting Director of the U.S. Patent and Trademark Office (USPTO) Coke Morgan Stewart finding that, because the validity of the ’865 patent had already been adjudicated in district court and substantial investment had already been made by the parties (including litigating preliminary injunctions through appeal), efficiency and integrity would be best served by invoking discretion to deny the petitions.

Simultaneously, Fresenius Kabi filed a second IPR petition, again challenging a previously unchallenged Regeneron patent, U.S. Patent No. 10,828,345 (the “’345 patent”) (IPR2025-01269). The ’345 patent relates to a method for treating an angiogenic eye disorder by sequentially administering a single initial dose of a VEGF antagonist, followed by one or more secondary doses, and one or more tertiary doses on a specific dosing schedule. While the Director declined to exercise discretion to deny Fresenius’ petition and referred it to the merits panel, institution was denied on January 9, 2026.

Finally, Alvotech USA also entered the arena in 2025, filing a PGR challenge against U.S. Patent No. 12,168,036 (the “’036 patent”) (PGR2025-00085). Similar to the ’345 patent, the ’036 patent relates to a method of treating an angiogenic eye using a formulation containing 8 mg of a VEGF receptor fusion protein. An institution decision is expected no later than April 8, 2026.

B. Keytruda^® (pembrolizumab)

In 2024, the PTAB instituted nine IPRs on behalf of Merck challenging patents held by Johns Hopkins University (JHU). The challenged patents were directed to methods of treating cancers with a particular biomarker with pembrolizumab (U.S. Patent Nos. 11,591,393, 10,934,356, 11,325,974, 11,325,975, 11,339,219, 11,649,287, 11,643,462, 11,629,187, and 11,643,491, in IPR2024-00240, 622, 623, 624, 625, 647, 653, 656, 650). Merck previously filed a declaratory judgment action in November 2022 in the District of Maryland, asserting claims of non-infringement of four of the challenged patents as well as breach of contract. Merck Sharp & Dohme LLC v. The Johns Hopkins University, 22-cv-3059 (D. Md.). JHU counter-claimed for infringement of those four patents, as well as an additional five patents or patent applications that later issued. Dkt. 15. Following institution of the first IPR against the ’393 patent, the District Court stayed the pending litigation in view of the remaining pending petitions. The PTAB issued Final Written Decisions across all nine proceedings between June and November 2025, finding all challenged claims unpatentable. JHU has filed notices of appeal for all nine proceedings, which the Federal Circuit has consolidated into a single appeal. Opening briefing is due on May 5, 2026.

C. Merck v. Halozyme (modified human hyaluronidase)

Over the course of the last year and starting in November 2024, Merck filed 15 PGR petitions challenging 15 separate patents related to Halozyme’s modified human hyaluronidase (MDASE) technology (U.S. Patent Nos. 11,952,600, 12,018,298, 12,152,262, 12,123,035, 12,110,520, 12,054,758, 12,060,590, 12,049,652, 12,104,185, 12,037,618, 12,091,692, 12,077,791, 12,195,773, 12,264,345, and 12,371,685, in PGR2025-00003, -4, -6, -9, -17, -24, -30, -33, -39, -42, -46, -50, -52, -53, and -87). To date, the Director has instituted trial on 14 of the 15 petitions. The institution deadline for the single remaining petition (PGR2025-00087) is May 20, 2026. Although Halozyme filed briefs requesting discretionary denial in response to the first 13 petitions, Halozyme waived its preliminary response in the 14 challenge (PGR2025-00052), thus accelerating the PTAB’s deadline to issue an institution decision. In April 2025, Halozyme filed a lawsuit in the District of New Jersey alleging that Merck’s subcutaneous Keytruda^®, Keytruda QLEX™, formulation containing berahyaluronidase alfa-pmph infringes Halozyme’s patents for modified hyaluronidases. Halozyme, Inc. v. Merck Sharp & Dohme Corp., 25-cv-3179 (D.N.J.). Halozyme seeks damages and an injunction. Final written decisions in the PGRs are expected between June and November 2026.

Relatedly, Halozyme also recently filed an IPR petition challenging Alteogen’s U.S. Patent No. 12,221,638, which relates to a method for producing a recombinant protein that comprises a hyaluronidase PH20 using specific culturing conditions (IPR2026-00176). Alteogen and Merck had entered into a license agreement related to the development of the subcutaneous formulation of Keytruda^®, Keytruda QLEX™. In Halozyme’s district court litigation against Merck, Halozyme seeks third party discovery from Alteogen, including Merck’s license agreement with Alteogen. See Halozyme, Inc. v. Merck Sharp & Dohme Corp., 25-cv-3179 (D.N.J.) (Dkt. 38). An institution decision is expected by June 2026.

D. Elevidys^® (delandistrogene moxeparvovec-rokl)

In June 2025, Sarepta Therapeutics filed two IPR petitions challenging Genzyme patents directed to a composition and method for storing purified recombinant adeno-associated virus (AAV) to avoid significant aggregation, U.S. Patent Nos. 9,051,542 and 7,704,721 (IPR2025-01194, -1195). In November 2025, the PTAB discretionarily denied both petitions without opinion, though it is worth noting that the ’542 patent and the ’721 patent had been in effect for 10 and 15 years, respectively, which could weigh in the Director’s “settled expectations” analysis. Genzyme had previously filed suit against Sarepta in district court in July 2024, alleging infringement of both patents. Genyzme Corp. v. Sarepta Therapeutics, Inc., 24-cv-00882 (D. Del.). In June 2025, however, Genzyme amended its complaint to add infringement allegations against five additional patents, U.S. Patent Nos. 12,013,326, 12,031,894, 12,298,313, 11,698,377, and 12,123,880. Dkt. 81. Subsequently, in December 2025, Sarepta filed IPR petitions challenging each in turn (IPR2025-00149, -150, -166, -167, -168). At a high level, these patents relate to methods for characterizing AAV preparations for various characteristics. Institution decisions on these petitions are expected by June 2026.

In another IPR challenge relating to Elevidys^®, Sarepta’s challenge to a patent held by the Trustees of the University of Pennsylvania and REGENXBIO came to an end in favor of the patent owners. In August 2024, the PTAB instituted trial on U.S. Patent No. 11,680,274, which is directed to a gene therapy vector using an adeno-associated virus (AAV) of a particular serotype — AAVrh4 6— or a protein 95% identical to that serotype (IPR2024-00580). Prior to the oral hearing, the patent owners voluntarily withdrew all challenged claims but one. The remaining claim — claim 8 — covers gene therapy constructs that use the AAVrh46 viral vector construct and deliver a shortened version of the dystrophin protein known as a mini-dystrophin or micro-dystrophin. In August 2025, the PTAB held claim 8 not unpatentable. Sarepta subsequently filed a notice of appeal in October 2025.

E. Opdivo^® + Yervoy^® (nivolumab + ipilimumab)

In February 2025, Amgen filed three IPR petitions challenging three Bristol-Myers Squibb patents relating to specific methods of treatment using a combination therapy of an anti-PD-1 antibody (i.e., nivolumab) and an anti-CTLA-4 antibody (i.e., ipilimumab). In July 2025, then-Acting Director Stewart discretionarily denied two of the petitions challenging U.S. Patent Nos. 9,856,320 and 10,174,113 (IPR2025-00601, -602). But Acting Director Stewart instituted the third petition challenging U.S. Patent No. 11,332,529 (IPR2025-00603). According to Acting Director Stewart, the differences between the patents’ issue dates led to different results. The ’113 and ’320 patents had been in force for six and seven years, respectively, which Acting Director Stewart found sufficient to invoke the “settled expectations” doctrine. By contrast, the ’529 patent had been in force only for three years. Notably, after the Acting Director referred the ’529 patent to a separate panel for a determination on the merits, Bristol-Myers Squibb statutorily disclaimed the challenged claims, ending the challenge.

F. Spikevax^® / Comirnaty^® (COVID-19 mRNA vaccine)

In March 2024, the PTAB instituted two IPR petitions by Pfizer challenging ModernaTX’s U.S. Patent Nos. 10,702,600 and 10,933,127 (IPR2023-01358, -1359). The ’600 patent is directed to an mRNA-based formulation encoding a betacoronavirus (BetaCoV) spike protein or subunit and delivered in a lipid nanoparticle. The ’127 patent is directed to a method of administering the betacoronavirus formulation in an amount effective to induce an immune response. In March 2025, the Board issued Final Written Decisions finding all challenged claims unpatentable as obvious. Both Final Written Decisions are on appeal at the Federal Circuit.

IV. Antitrust litigation concerning biologics and biosimilars

Antitrust litigation involving biologics continued to develop in 2025. Payors and biosimilar makers increasingly challenged patent acquisition and enforcement conduct, as well as contracting practices and bundled rebate arrangements, as anticompetitive conduct under federal and state antitrust law. These cases test the boundary between protected patent acquisition and enforcement activity, proper contracting practices, and actionable anticompetitive conduct. As discussed below, antitrust plaintiffs have advanced Walker Process fraud and sham litigation theories, sought to limit the reach of Noerr-Pennington immunity where patent enforcement allegedly delays biosimilar entry, characterized patent acquisitions as monopolistic behavior, and challenged bundled rebate arrangements as unlawful exclusionary conduct.

A. CareFirst v. Johnson & Johnson (Stelara^®) — Walker Process fraud and patent acquisition theories

In CareFirst of Maryland, Inc. v. Johnson & Johnson, No. 23-cv-629 (E.D. Va.), originally filed in December 2023, third-party payors alleged that Johnson & Johnson (J&J) delayed ustekinumab biosimilar competition through (a) fraud on the USPTO, (b) acquisition of certain manufacturing patents from Momenta, and (c) patent enforcement and settlement activity that allegedly delayed biosimilar entry.

In December 2025, the court certified damages and unjust enrichment classes as to federal and most state antitrust claims, finding the proposed classes sufficiently numerous and that common issues of exclusionary conduct and injury predominated. The court declined to certify the proposed classes as to certain state consumer protection claims.

That same month, the court issued rulings on the parties’ summary judgment motions. 2025 WL 3634085. On monopoly power, the court found genuine disputes of material fact regarding the relevant product market and competitive effects. Id. at *10–11. On the Walker Process theory, the court held that CareFirst had raised triable issues as to materiality and intent with respect to certain alleged omissions and misrepresentations during patent prosecution while narrowing other aspects of the fraud allegations. Id. at *11–16. The court also denied summary judgment on whether J&J’s acquisition of Momenta’s manufacturing patents could constitute willful maintenance of monopoly power, finding that a genuine dispute existed as to whether the acquisition was motivated by an intent to exclude rather than efficiency or other legitimate business considerations. Id. at *16–19. Lastly, the court allowed CareFirst’s antitrust injury theory to proceed, finding that a reasonable jury could conclude that, but for J&J’s patent acquisition and enforcement, biosimilar entry would not have been delayed through settlement. Id. at *20.

Following those decisions, however, the case did not proceed to trial as scheduled in January 2026. After reconsideration of its summary judgment decision and further pretrial proceedings, the parties advised the court that the remaining issues did not warrant trial on the existing record and final judgment was entered in J&J’s favor.

B. Regeneron v. Amgen (Repatha^®, Enbrel^®, Otezla^®) — Bundling

Regeneron and Amgen compete by selling Praluent^® and Repatha^®, PCSK9 inhibitors that help high-risk patients lower LDL cholesterol levels. In Regeneron Pharmaceuticals, Inc. v. Amgen Inc., No. 22-cv-697 (D. Del.), filed in 2022, Regeneron challenged Amgen’s contracting practices in the PCSK9 inhibitor market, alleging that Amgen used “substantial rebates on entirely unrelated medications in Amgen’s portfolios” and bundled Repatha^® with high-revenue products such as Otezla^® and Enbrel^® to block competition from Regeneron’s Praluent^®. Dkt. 1 ¶¶ 1–4.

In May 2025, following a seven-day trial, a jury returned a verdict in favor of Regeneron, awarding over $400 million in damages and finding that Amgen’s bundling of Repatha^® with Enbrel^® and Otezla^® violated Sections 1 and 2 of the Sherman Act and related state tort law. Dkt. 479 at 2–5. The jury found for Amgen on one count: violation of California’s Unfair Practices Act. Id. at 4. Post-trial motions remain pending.

C. CareFirst v. Amgen and Sandoz v. Amgen (Enbrel^®) — Patent acquisition theory

In CareFirst of Maryland, Inc. v. Amgen, Inc., No. 24-cv-484 (E.D. Va.), payors allege that Amgen unlawfully maintained monopoly power in the etanercept market by acquiring exclusive patent rights from Roche related to etanercept and entering into settlement agreements related to those patents to delay U.S. biosimilar entry until 2029.

In September 2025, the court largely denied Amgen’s motion to dismiss the second amended complaint, permitting CareFirst’s federal monopolization claims and most related state law claims to proceed. Dkt. 66 at 56–57. Notably, the court held that while Amgen’s prosecution and enforcement activity was generally protected under the Noerr-Pennington doctrine, the alleged “anticompetitive conduct of purchasing the Roche Patent Rights,” including rights in pending patent applications, may constitute independent conduct subject to antitrust scrutiny. Id. at 24, 26, 32–35. The court further found that the complaint plausibly alleged monopoly power, delayed biosimilar entry, and antitrust injury. Id. at 23, 35, 40–42.

In Sandoz Inc. v. Amgen Inc., 25-cv-218 (E.D. Va.), a parallel case brought by a biosimilar competitor in April 2025, Sandoz similarly asserted Sherman Act Section 2 and related state law claims, alleging that Amgen’s patent acquisition and enforcement “scheme” unlawfully delayed Sandoz’s launch of its etanercept biosimilar, resulting in in more than $1 billion in lost sales. Amgen moved to dismiss the complaint, and in February 2026, the court granted Amgen’s motion, holding that Sandoz’s federal antitrust claim was a compulsory counterclaim that should have been raised in the 2016 BPCIA litigation against Amgen related to its etanercept biosimilar. Dkt. 39 at 30. The court dismissed the Sherman Act claim with prejudice and declined to exercise supplemental jurisdiction over Sandoz’s state law claims, dismissing them without prejudice with leave to refile in state court. Id. at 31.

D. EmblemHealth v. Alexion (Soliris^®) — Sham litigation and Walker Process fraud

In EmblemHealth, Inc. v. Alexion Pharms., Inc., No. 25-cv-10985 (D. Mass.), filed in April 2025, insurer EmblemHealth alleged that Alexion fraudulently obtained from the USPTO a set of five follow-on patents after the expiration of its original eculizumab patent in 2021 and entered into settlements that delayed biosimilar entry and maintained supra-competitive pricing for eculizumab. Dkt. No. 1 at ¶¶ 4–8. The complaint asserts Sherman Act Section 2 claims for monopolization, monopolistic scheme, and attempted monopolization, as well as related state law claims.

In December 2025, the court dismissed EmblemHealth’s Walker Process-based claims, holding that EmblemHealth, as an indirect purchaser, lacked standing to pursue such claims because the alleged fraud on the USPTO was “too far removed” from the alleged injuries, with too many intervening intermediaries. Dkt. 49 at 17. However, the court permitted EmblemHealth’s Sherman Act claims based on alleged sham litigation to proceed, concluding that Noerr-Pennington immunity did not bar the claims at the pleadings stage because EmblemHealth had sufficiently pled facts that Alexion knowingly obtained certain patents through material misrepresentations and omissions such that EmblemHealth may be able to demonstrate that no reasonable litigant could expect to succeed in a lawsuit to enforce a valid patent. As for the state claims, the parties agreed that the merits of EmblemHealth’s various state law claims generally all rise and fall with EmblemHealth’s antitrust claims, and the court held that only EmblemHealth’s claims alleging sham litigation survived. Id. at 24.

On January 8, 2026, EmblemHealth filed a motion for partial reconsideration and clarification of the court’s decision on Alexion’s motion to dismiss. Dkt. 58. The motion remains pending.

V. 2025 U.S. regulatory updates for biologics and biosimilars

FDA advanced several initiatives in 2025 to streamline biosimilar development and clarify interchangeability status of biosimilar drugs.

A. FDA moves to eliminate comparative clinical efficacy trials

In October 2025, FDA issued draft guidance titled “Scientific Considerations in Demonstrating Biosimilarity to a Reference Product: Updated Recommendations for Assessing the Need for Comparative Efficacy Studies.” This guidance proposes eliminating the default requirement for Phase III comparative clinical efficacy trials (CES), which have historically been the most costly and time-consuming parts of biosimilar development. Per the guidance, in many instances, a biosimilar may be approved without a CES if comparative analytical data, together with pharmacokinetic similarity data and immunogenicity assessments, sufficiently address any residual uncertainty regarding safety and efficacy.

Public comments to this guidance have been submitted by a number of interested stakeholders, including reference biologic and biosimilar developers, industry groups, insurers, and academic institutions, among others. The comment period for the draft guidance closed in January 2026. 90 Fed. Reg. 222 (Nov. 22, 2025).

The impact of implementing this proposal could be significant in that it could save manufacturers years of development time and hundreds of millions of dollars in costs, thereby accelerating BLA submissions.

B. Interchangeability: Policy vs. practice

In announcing the CES reform, Health and Human Services (HHS) and FDA made clear their intent to simplify and accelerate biosimilar adoption by treating biosimilars and interchangeables as functionally equivalent for most therapeutic proteins. As a reminder, interchangeability status allows pharmacists to substitute biosimilar products for their reference biologics without prescriber approval, subject to state laws. As HHS and FDA announced in an October 2025 press release: “By streamlining the biosimilar development process and helping advance interchangeability, we can achieve massive cost reductions for advanced treatments for cancer, autoimmune diseases, and rare disorders affecting millions of Americans.”

FDA’s updated guidance and public statements reinforce this practical shift. As the Director of the Office of Therapeutic Biologics and Biosimilars has previously stated, “Both biosimilars and interchangeable biosimilars meet the same high standard of biosimilarity for FDA approval and both are as safe and effective as the reference product.”

In practice, FDA appears to be moving toward automatic interchangeability for most therapeutic proteins, eliminating the need for costly switching studies. The recent uptick in interchangeable biosimilar approvals reflects FDA’s evolving regulatory practice.

C. Promotional labeling and advertising guidance finalized

In December 2025, FDA issued final guidance governing promotional labeling and advertising for biosimilars, interchangeable biosimilars, and reference biologic products. The guidance outlines requirements for accuracy, truthfulness, and clarity in promotional materials, emphasizing that communications must not be misleading and must fairly represent the relationship between biosimilars and their reference products. The document also provides specific recommendations and examples for comparative claims, including with respect to the use of interchangeability status and the presentation of clinical data. The guidance aims to ensure that healthcare professionals and patients receive reliable information as biosimilar adoption expands, and it clarifies regulatory expectations for manufacturers preparing marketing materials for both newly approved and established biologic therapies.

D. Expanded access to investigational drugs

In October 2025, FDA released updated guidance on expanded access to investigational drugs, including biologics, for treatment use outside of traditional clinical trials. The revised document clarifies the process by which patients and healthcare providers can request access to investigational therapies when no satisfactory alternatives are available and participation in a clinical trial is not feasible. The guidance details the criteria for eligibility, the roles of sponsors and physicians, and the documentation required for submission. It also addresses safety monitoring and reporting obligations, aiming to streamline the pathway for patients with serious or life-threatening conditions to obtain investigational biologic drugs under “compassionate use” or expanded access programs.

E. Reduction of animal testing for monoclonal antibodies

In December 2025, FDA issued draft guidance recommending a reduction or elimination of six-month toxicity testing in non-human primates for certain monoclonal antibody products. There, the agency identified specific product categories where alternative evidence streams, such as computational toxicology models and organoid systems, may be sufficient to support safety assessments. The guidance reflects ongoing efforts to modernize regulatory science, reduce reliance on animal testing, and encourage the adoption of innovative methodologies. FDA’s recommendations are expected to impact preclinical development strategies for monoclonal antibodies, potentially accelerating timelines and reducing costs for manufacturers.

F. CAR-T therapy approval standards

In a 2025 JAMA article, FDA’s biologics chief outlined the FDA’s policy shift requiring developers of chimeric antigen receptor T-cell (CAR-T) therapies to demonstrate superiority over existing treatments through randomized controlled trials as a condition for approval. The new standard raises the evidentiary bar for cell therapies in oncology, moving beyond single-arm studies and historical controls. FDA officials indicated that the change is intended to ensure robust comparative data on efficacy and safety, supporting informed decision-making by clinicians and payors. The policy is expected to influence clinical trial design and development strategies for CAR-T products seeking regulatory approval in the U.S., although many of the seven CAR-T therapies approved in the U.S. already included at least one trial compared to an active control. The impact of this shift remains unclear, as current CAR-T developers already have ongoing comparator trials.

G. Use of artificial intelligence in regulatory decision-making

In January 2025, FDA released draft guidance on the use of artificial intelligence (AI) models to support regulatory decision-making for drugs and biologic products. The document introduces a risk-based framework for assessing the credibility of AI-generated evidence, including requirements for transparency, reproducibility, and validation. It also addresses the use of AI in areas such as clinical trial design, safety signal detection, and manufacturing quality control. FDA’s initiative reflects the growing role of AI in biomedical research and regulatory science and provides manufacturers with a pathway to incorporate advanced analytics into submissions for drug and biologic approvals.

VI. Policy and legislation affecting biologics and biosimilars

2025 saw policy and legislative activities aimed at reducing drug prices and promoting competition in the pharmaceutical industry.

A. Proposed federal legislation

Congressional activity in 2025 largely built on proposals advanced in the prior Congress, reflecting continued bipartisan interest in lowering barriers to biosimilar entry and reducing drug costs. As in 2024, the legislative focus centered on antitrust enforcement tools targeting perceived anticompetitive lifecycle management practices, proposals to narrow or streamline patent assertion in BPCIA litigation, broader patent system reforms with potential downstream effects on biologics and biosimilars, and regulatory measures aimed at accelerating biosimilar approval and uptake.

Antitrust reforms

In March 2025, Sens. Cornyn, Blumenthal, Grassley, and Durbin introduced the Drug Competition Enhancement Act (S.1040), which would amend the FTC Act to make “product hopping” an antitrust violation. The bill addresses so-called “hard switches” and “soft switches”. If enacted, the bill could increase antitrust scrutiny of product transition strategies in the run-up to anticipated biosimilar competition, potentially reshaping defensive lifecycle management planning for reference product sponsors.

Congress also revisited legislation concerning so-called “reverse payment” or “pay-for-delay” settlement agreements in 2025. The Preserve Access to Affordable Generics and Biosimilars Act (S. 1096), introduced in March 2025, would make certain settlement agreements presumptively unlawful where a generic or biosimilar applicant receives “anything of value” and “agrees to limit or forgo research, development, manufacturing, marketing, or sales” of its product. This bill closely tracks prior iterations and was placed on the Senate Legislative Calendar in April 2025.

Patent assertion limits in BPCIA litigation

A companion bill to S.1040 discussed above, the Affordable Prescriptions for Patients Act (S. 1041) would amend 35 U.S.C. § 271(e) to limit the number of patents a reference product sponsor may assert in BPCIA litigation, subject to defined conditions and exceptions, including the biosimilar applicant’s completion of specified steps of the BPCIA information exchange process. Like the ETHIC Act discussed below, this proposal has been framed by sponsors as a response to perceived “patent thickets” in the biologics space and broader concerns about the scope of patent assertion in BPCIA litigation. The 2025 version of the bill substantially tracks the version that passed the Senate in 2024. If enacted in its current form, the bill likely would require earlier prioritization of key patents and could make compliance with the patent dance more consequential. Questions regarding patent dance compliance that currently affect timing, litigation scope, or procedural posture could instead determine whether the numerical cap on asserted patents applies at all, potentially increasing the practical importance of the BPCIA pre-litigation information exchanges.

In July 2025, Sens. Welch, Hawley, and Klobuchar introduced the Eliminating Thickets to Increase Competition (ETHIC) Act (S. 2276), which would similarly limit patents asserted in BPCIA litigation by restricting reference product sponsors to one patent per “group” (defined as commonly owned patents related to one another through terminal disclaimers or obviousness-type double patenting). An identical bill was introduced in May 2025 in the House as H.R. 3269 by Reps. Arrington, Doggett, Issa, Jayapal, and Pfluger. The language of the bills is identical to the version introduced in January 2024.

Broader patent reforms

Two additional reintroduced proposals, the Promoting and Respecting Economically Vital American Innovation (PREVAIL) Act (S. 1553 and H.R. 3160) and the Patent Eligibility Restoration Act (PERA) (S. 1546 and H.R. 3152), are not specific to biologics but could nevertheless materially impact patent practice in the life sciences space. The PREVAIL Act would revise post-grant proceedings before the USPTO in ways intended to align certain standards more closely with those applied in district court litigation, including changes to standing and burdens of proof. PERA would amend 35 U.S.C. § 101 by specifying categories of patent-ineligible subject matter, including, among others, an “unmodified human gene, as that gene exists in the human body” and an “unmodified natural material, as that material exists in nature.”

Regulatory reforms for biosimilars

In addition to patent- and antitrust-focused reforms, several legislative proposals from 2025 targeted the regulatory pathway for biosimilars. The Biosimilar Red Tape Elimination Act (S. 1954 and H.R. 5526) would eliminate the statutory distinction between biosimilarity and interchangeability, such that a biosimilar would be “deemed” interchangeable upon initial FDA approval. The Skinny Labels, Big Savings Act (S. 43) would amend 35 U.S.C. § 271 to establish a statutory safe harbor from patent infringement claims for generic or biosimilar manufacturers that seek approval for, or market, products with FDA-approved “skinny labels.” The Expedited Access to Biosimilars Act (S. 1414) would modify clinical study requirements by permitting the Secretary of HHS to limit required studies to immunogenicity, pharmacodynamic, or comparative efficacy assessments where appropriate.

Additional legislative proposals

Several additional bills newly introduced and re-introduced in 2025 could also affect the biologics and biosimilars landscape. These include:

• Prescription Pricing for the People Act of 2025 (S. 527), which would require the Federal Trade Commission (FTC) to report on anticompetitive conduct by pharmacy benefit managers, competition trends in the healthcare supply chain, intermediary practices and transparency, and legal or regulatory obstacles that contribute to anticompetitive conditions and prescription drug prices. This bill is a reintroduced version of similarly titled bills in prior Congressional sessions.
• Prescription Drug Price Relief Act (S. 1818 and H.R. 3546), which would direct the Secretary of HHS to determine whether certain brand-name drugs are priced excessively and, if so, waive or void applicable government-granted exclusivities with respect to such drugs and grant open, non-exclusive licenses with reasonable royalties, allowing others to develop and market such drugs relying on the original test data.
• Stop STALLING Act (S. 1095), which would make it an unfair method of competition to submit an objectively baseless petition to FDA in an attempt to interfere with a competitor’s application for market approval of a drug or biologic product.
• Stopping Pharma’s Ripoffs and Drug Savings For All Act (H.R. 890), which would amend 35 U.S.C. § 253 to create a presumption that a patentee has disclaimed the patent term of certain listed patents beyond the expiration of the earliest-expiring patent, unless the patentee demonstrates that the patents cover patentably distinct inventions.

Collectively, these proposals reflect a sustained congressional focus on reshaping the competitive landscape for biologics through antitrust, patent, and regulatory reform. Even if individual measures stall, the direction of legislative activity signals continued scrutiny of both patent enforcement strategies and regulatory pathways for biosimilars. 

B. Executive orders and policy developments

In addition to congressional activity, the Trump administration signaled continued interest in reducing drug prices and fostering competition from lower-cost alternative drug products, such as biosimilars, in 2025. Executive Orders issued in April and May 2025 directed HHS and other agencies to pursue “most-favored-nation” pricing approaches to address disparities in U.S. drug prices relative to other developed countries, encourage development and accelerated approval of generic and biosimilar products, and develop recommendations to address perceived anticompetitive behavior from in the pharmaceutical industry.

C. Inflation Reduction Act

The Inflation Reduction Act (IRA) established a framework for Medicare to negotiate with drug manufacturers on prices of certain high-expenditure drugs lacking generic or biosimilar competition. With the first set of negotiated prices taking effect in 2026, the price negotiation program has moved from a statutory framework to one with direct commercial and strategic implications for drug manufacturers, including biologics companies.

In January 2026, the Centers for Medicare and Medicaid Services (CMS) announced the selection of 15 drugs for the third negotiation cycle (Initial Price Applicability Year (IPAY) 2028). While initial cycles skewed toward small molecule drugs, several of the products selected for IPAY 2028 were biologics listed in FDA’s Purple Book, including monoclonal antibody therapeutics such as Orencia, Cosentyx, Entyvio, Xolair, and Cimzia. CMS also published a list of the “Top 50 Negotiation-Eligible Drugs” for IPAY 2028, which includes numerous additional high-revenue biologics.

These developments underscore that biologics are increasingly within the scope of the IRA’s negotiation framework. Although inclusion of a product on the “Top 50” list does not guarantee selection for negotiation, it identifies products that meet statutory eligibility criteria and may remain within CMS’ focus in future negotiation cycles. As biologics increasingly enter the negotiation framework, reference biologic makers may factor negotiation exposure into portfolio strategy, lifecycle planning, and expectations regarding biosimilar competition.

Lastly, since the IRA’s enactment, multiple manufacturers and trade groups have challenged the negotiation program on constitutional and Administrative Procedure Act grounds, including claims under the Takings Clause, Due Process Clause, and the First Amendment. Multiple appellate and district courts have rejected rejecting these challenges. Petitions seeking Supreme Court review have been filed, but as of early 2026 the program continues to operate while litigation proceeds.

Conclusion

2025 saw a continued maturation of the U.S. biosimilars market, with expanding approvals and launches; sustained development activity; increased multi-defendant BPCIA litigation centered on denosumab and aflibercept; and growing antitrust challenges and legislative proposals addressing patent acquisition, assertion, and contracting practices.

Looking forward, these trends may continue to develop in 2026. The denosumab and aflibercept BPCIA litigations suggest that coordinated MDL proceedings could become more common for reference biologics facing multiple biosimilar challengers. As additional high-revenue biologics approach the end of regulatory exclusivity, increased BPCIA litigation appears likely. At the same time, evolving FDA guidance, proposed legislation, and IRA implementation suggest that the legislative and regulatory environment may continue to shift in ways that affect lifecycle management strategies and expectations for biosimilar entry and settlement. Taken together, these forces are shaping when biosimilars launch, how disputes are resolved, and how products are priced.

Appendix A: Biosimilars Approved as of 2025

Appendix B: Ongoing and Settled BPCIA Cases From 2025