US Patent 10,035,822: Claim Scope, Pegcetacoplan Coverage, and Compstatin Patent Landscape
US Patent No. 10,035,822 protects a long-acting, dimeric compstatin construct in which two cyclic compstatin analogs are attached to the opposite ends of a linear clearance-reducing polymer, principally PEG, through carbamate linkages and oligoethylene glycol-containing spacers. The claim architecture is closely aligned with pegcetacoplan, the active ingredient in Empaveli and Syfovre, although product coverage depends on the sequence, linker, polymer, linkage chemistry, and Orange Book listing applicable to each approved product.
The patent was issued on July 31, 2018. Its commercial significance is highest for long-acting C3 inhibitors based on a 40 kDa PEG-linked compstatin dimer. The core composition claims are stronger than the pharmacokinetic and relative-potency limitations because claims 9 through 11 add performance requirements that may create evidentiary and infringement issues.
What does US Patent 10,035,822 protect?
The patent protects a specific molecular architecture rather than compstatin inhibitors generally.
| Claim element |
Required limitation |
| Active pharmacophore |
Two compstatin analog moieties |
| Peptide structure |
Cyclic peptide, extended by lysine at the N-terminus, C-terminus, or both |
| Spacer |
Rigid or flexible spacer containing oligoethylene glycol |
| Spacer alternatives |
A covalently joined -(CH2)m- and -(O-CH2-CH2-)n structure, or AEEAc/related amino acid spacer |
| Clearance-reducing moiety |
Linear polymer |
| Polymer attachment |
Each polymer end linked to one compstatin moiety through a carbamate |
| Polymer examples |
PEG or polyoxazoline |
| Preferred polymer |
PEG |
| Preferred molecular weight |
About 40 kDa |
| Performance limitations |
At least three- or five-day terminal half-life in a primate, or at least 90% molar activity relative to the unconjugated analog |
The independent claim requires all of these structural features. A competing molecule that has only one compstatin moiety, a branched rather than linear polymer, a non-carbamate linkage, or a materially different spacer may fall outside claim 1 even if it inhibits C3.
The use of "comprising" makes claim 1 open-ended. A molecule may contain additional structural elements and still infringe if it includes every required claim element. The claim does not, however, eliminate the need to prove the specific two-arm, polymer-linked architecture.
How does claim 1 map onto pegcetacoplan?
Pegcetacoplan is a targeted C3 inhibitor composed of a compstatin-based peptide dimer linked through a high-molecular-weight PEG moiety. FDA labeling identifies pegcetacoplan as the active ingredient in Empaveli and Syfovre [1, 2].
The apparent product-to-claim correspondence is as follows:
| Pegcetacoplan characteristic |
Claim 1 relevance |
| Dimeric compstatin-based inhibitor |
Satisfies the two-compstatin-moiety framework if the product sequence falls within the claimed analog structure |
| PEG clearance-reducing group |
Expressly covered by claims 6 and 7 |
| Approximately 40 kDa PEG |
Expressly addressed by claim 8 |
| Peptide extension and linker chemistry |
Central to the scope of claim 1 |
| Long systemic exposure |
Consistent with claims 9 and 10, but not necessary for infringement of claim 1 |
| High retained molar activity |
Relevant to claim 11 if the limitation is asserted |
The strongest product-facing claims are claims 1, 6, 7, 8, and 12. Claim 12 narrows protection to the cyclic peptide sequence identified as SEQ ID NO: 28. If the commercial product uses that sequence and the claimed linker and polymer configuration, claim 12 may provide a more focused product claim than the broader sequence-set claim 2.
The claim text alone does not establish whether every molecular detail of commercial pegcetacoplan is identical to SEQ ID NO: 28 or to each claimed spacer alternative. Patent prosecution history, the sequence listing, the issued specification, and the product's detailed chemical characterization control that determination.
What do claims 2 through 8 add?
Claims 2 through 8 create nested composition coverage.
Claims 2 and 12: sequence-specific protection
Claim 2 covers cyclic peptides having any sequence identified in SEQ ID NOs: 3-36, 71-74. Claim 12 narrows that group to SEQ ID NO: 28.
This structure gives the patent two levels of sequence protection:
- A broad list of expressly identified cyclic peptide sequences.
- A focused claim to the sequence in SEQ ID NO: 28.
A generic or follow-on developer cannot avoid these claims merely by changing a nonessential residue if the resulting molecule still meets the literal sequence limitation. Conversely, a strategically selected analog outside the listed sequences may avoid claims 2 and 12 while remaining exposed to claim 1 if the broader structural limitations are met.
Claims 3 through 5: spacer protection
Claims 3 and 4 cover the joined alkylene and oligoethylene glycol spacer, with claim 4 specifying m = 1 and n = 2. Claim 5 separately covers AEEAc and 11-amino-3,6,9-trioxaundecanoic acid.
These claims target the attachment region between the cyclic peptide and the polymer. They reduce design-around options involving minor linker modifications. A competitor using a different spacer may avoid the dependent claims while still infringing claim 1 if the alternative spacer satisfies the broad claim language.
Claims 6 through 8: polymer and molecular-weight protection
Claim 6 covers PEG and polyoxazoline. Claim 7 narrows the polymer to PEG. Claim 8 narrows PEG to an average molecular weight of about 40 kDa.
The 40 kDa limitation is commercially important because polymer size affects renal clearance, tissue distribution, dosing interval, immunogenicity, and manufacturing controls. "About 40 kDa" is not limited to one exact molecular-weight value. The specification's analytical methods, molecular-weight distribution, and prosecution record would inform the permissible range.
How strong are the half-life and potency claims?
Claims 9 through 11 add functional limitations:
| Claim |
Functional requirement |
Enforcement significance |
| 9 |
Terminal half-life of at least about three days in a primate |
Requires pharmacokinetic proof |
| 10 |
Terminal half-life of at least about five days in a primate |
Narrower and more commercially aligned with long-acting exposure |
| 11 |
At least 90% molar activity versus the corresponding unconjugated analog |
Requires comparative potency testing |
Claims 9 and 10 are narrower than claim 1 and may be useful where the accused product's structure is disputed but its pharmacokinetic profile is clear. They also create potential claim-construction disputes involving:
- The meaning of "terminal half-life."
- The tested primate species.
- The dosing route and dose.
- Whether the measurement must be made in a healthy or disease-model animal.
- The appropriate unconjugated comparator under claim 11.
- The assay used to determine molar activity.
Claims 9 through 11 are less attractive as primary composition claims when claims 1, 7, 8, or 12 can establish infringement without proving a clinical or preclinical performance parameter.
When does US Patent 10,035,822 lose exclusivity?
The patent issued from a pre-America Invents Act filing framework and has a nominal 20-year term measured from the applicable earliest nonprovisional or international filing date, subject to patent-term adjustment, terminal disclaimers, and any patent-term extension.
The relevant commercial timeline is:
| Event |
Date or period |
| Patent issued |
July 31, 2018 |
| Expected base-term endpoint |
Approximately July 2033, based on the reported priority and international filing chronology |
| Earliest likely generic or follow-on launch |
After enforceable patent and regulatory barriers expire, unless a successful challenge occurs |
| Possible regulatory extension |
A qualifying patent-term extension could affect the effective endpoint, but any extension must be confirmed in the USPTO and Orange Book records |
For business planning, the patent should be treated as a 2033-era asset unless a later patent, patent-term extension, settlement, or litigation outcome changes the effective barrier. The commercial exclusivity of pegcetacoplan does not depend on this patent alone.
What is the Orange Book status of the patent?
FDA Orange Book protection for a drug product is determined by the patents listed for the specific approved product, not by a general association between a patent and an active pharmaceutical ingredient [3].
Empaveli and Syfovre have separate approved indications, dosage forms, labeling, and product presentations. Their listed patent estates may therefore differ even though both contain pegcetacoplan. The practical questions are:
- Whether US 10,035,822 is listed against Empaveli, Syfovre, or both.
- Whether the listing covers the active ingredient, formulation, method of use, or drug product.
- Whether the patent is still listed and unexpired.
- Whether an approved indication is protected by a listed method-of-use claim.
For an ANDA applicant, an Orange Book listing can trigger a Paragraph IV certification and potential 30-month stay under the Hatch-Waxman Act if the innovator brings suit within the statutory period [4]. A patent not listed in the Orange Book may remain enforceable but generally does not create the same ANDA certification mechanism.
What patent landscape surrounds pegcetacoplan?
US 10,035,822 is one component of a layered patent estate. The relevant categories are:
| Estate layer |
Protected subject matter |
Commercial purpose |
| Platform composition patents |
Compstatin analog sequences and long-acting conjugates |
Protect the molecular platform |
| Product composition patents |
Pegcetacoplan structure and chemical configuration |
Protect the approved molecule |
| Formulation patents |
Concentration, excipients, stability, and injectable presentation |
Delay product substitution |
| Method-of-use patents |
PNH, geographic atrophy, kidney disease, hematologic and complement-mediated indications |
Protect indication-specific use |
| Manufacturing patents |
Peptide synthesis, conjugation, purification, and control of polymer distribution |
Raise technical entry costs |
| Continuations and divisionals |
Narrower sequence, linker, polymer, or use claims |
Preserve prosecution flexibility |
Apellis Pharmaceuticals is the principal commercial sponsor of pegcetacoplan. The product was approved as Empaveli for adults with paroxysmal nocturnal hemoglobinuria in 2021 and as Syfovre for geographic atrophy secondary to age-related macular degeneration in 2023 [1, 2, 5].
The platform patent is commercially important because it can reach the drug substance itself. Formulation and method-of-use patents may remain relevant after a composition patent expires, particularly for a generic seeking approval for a protected indication or dosage form.
What generic entry risks exist?
Small-molecule generic risk
Pegcetacoplan is a chemically synthesized peptide conjugate, not a conventional small molecule. An ANDA applicant would face substantial analytical and manufacturing demands involving:
- Peptide sequence and conformation.
- Disulfide or cyclic structure, where applicable.
- PEG attachment sites.
- Carbamate and spacer chemistry.
- Polymer molecular-weight distribution.
- Dimeric stoichiometry.
- Aggregation and impurity profiles.
- Biological activity and complement inhibition.
An ANDA pathway may be difficult if the product's complexity prevents a straightforward demonstration of pharmaceutical equivalence and bioequivalence. A 505(b)(2) strategy could be more practical for a materially different formulation or delivery approach, although it would not eliminate patent risk [6].
Biosimilar risk
Pegcetacoplan is not a biologic licensed under the Public Health Service Act merely because it is a peptide-based therapeutic. A conventional biosimilar pathway is therefore not the default route. The more relevant competition model is a complex generic, 505(b)(2) product, or another C3 inhibitor with a different molecular structure.
A follow-on product that is not pegcetacoplan could avoid direct composition claims but still compete clinically. A product with a different compstatin sequence, polymer, linker, or administration route would require a separate freedom-to-operate analysis.
Which companies are challenging the patent estate?
No publicly established Paragraph IV judgment against US 10,035,822 is identified in the materials provided. The absence of a reported challenge does not eliminate future risk. A generic applicant could challenge validity or scope based on:
- Lack of written description across the broad sequence and spacer genus.
- Enablement of the full range of polymers, linkers, sequences, and half-life outcomes.
- Obviousness based on known compstatin analogs and PEGylation techniques.
- Indefiniteness involving "about 40 kDa," "terminal half-life," or "at least 90%."
- Noninfringement based on a different linkage, spacer, polymer architecture, or sequence.
The best invalidity targets are likely the broad genus aspects of claim 1 and the functional limitations of claims 9 through 11. The best infringement positions are likely the narrower, structurally defined claims covering PEG, approximately 40 kDa molecular weight, specified sequences, and identified spacers.
What licensing and manufacturing barriers matter?
Compstatin technology originated in academic complement research associated with the University of Pennsylvania and John D. Lambris's research group. Commercial development has been conducted through licensing and corporate transactions involving complement-inhibitor assets, including Apellis's acquisition and development of the APL-2/pegcetacoplan program [5, 7].
Manufacturing remains a meaningful barrier because the product combines:
- A cyclic peptide active region.
- Site-specific conjugation.
- A high-molecular-weight PEG component.
- Dimeric architecture.
- Tight control of molecular-weight distribution.
- Sterile injectable production.
A competitor may avoid literal patent infringement yet still face process-development, characterization, comparability, and regulatory hurdles. These barriers are stronger for an intravitreal product, where particulate matter, aggregation, injection-device compatibility, and local ocular tolerability are critical.
How does US 10,035,822 compare with competing complement inhibitors?
| Product or program |
Target |
Modality |
Relationship to US 10,035,822 |
| Empaveli |
C3 |
PEG-linked compstatin analog |
Directly relevant |
| Syfovre |
C3 |
PEG-linked compstatin analog |
Directly relevant |
| Pegcetacoplan follow-ons |
C3 |
Potential complex generic or 505(b)(2) product |
Direct composition and formulation risk |
| Eculizumab |
C5 |
Monoclonal antibody |
No direct composition overlap |
| Ravulizumab |
C5 |
Long-acting monoclonal antibody |
No direct composition overlap |
| Iptacopan |
Factor B |
Small molecule |
No direct composition overlap |
| Danicopan |
Factor D |
Small molecule |
No direct composition overlap |
| Other C3 inhibitors |
C3 |
Antibody, peptide, or small molecule |
Product-specific analysis required |
US 10,035,822 is not a patent on C3 inhibition as a therapeutic concept. It is a platform and product-architecture patent focused on long-acting compstatin analogs.
Key Takeaways
- US 10,035,822 covers a two-arm compstatin analog linked to a linear clearance-reducing polymer through carbamate linkages.
- PEG, approximately 40 kDa PEG, specified oligoethylene glycol spacers, and selected peptide sequences are central limitations.
- Claim 12 provides focused protection for SEQ ID NO: 28.
- Claims 9 through 11 add half-life and potency requirements but create additional proof burdens.
- The patent is expected to have a base-term endpoint in approximately 2033, subject to patent-term adjustments, extensions, and related patent rights.
- Pegcetacoplan's practical exclusivity depends on a broader estate covering composition, formulation, methods of use, and manufacturing.
- Generic competition is more likely to arise through a complex generic or 505(b)(2) pathway than through a conventional biosimilar application.
- The main technical design-arounds are sequence substitution, alternative polymer architecture, non-carbamate linkage chemistry, and different spacer design.
FAQs About US Patent 10,035,822
Does US Patent 10,035,822 cover Empaveli?
It may cover Empaveli if the commercial pegcetacoplan molecule satisfies the claimed sequence, spacer, carbamate linkage, linear polymer, and dimeric architecture. Product-specific coverage depends on the issued patent record and applicable Orange Book listing.
Does US Patent 10,035,822 cover Syfovre?
The same molecular-structure analysis applies to Syfovre. Because Syfovre and Empaveli contain pegcetacoplan but have different approved uses and presentations, their Orange Book patent listings may not be identical.
Can a competitor avoid the patent by using a different PEG size?
A different PEG size may avoid claim 8, but it will not necessarily avoid claim 1 or claims 6 and 7. The competitor would also need to assess the claimed polymer, carbamate linkages, spacer, peptide sequence, and two-moiety structure.
Is a 40 kDa PEG requirement essential to claim 1?
No. The approximately 40 kDa limitation appears in claim 8, not claim 1. Claim 1 requires a clearance-reducing linear polymer but does not expressly require a 40 kDa PEG.
What is the most commercially important claim?
Claim 1 is the principal broad composition claim. Claims 7, 8, and 12 are narrower but potentially more valuable in a product-specific enforcement action because they focus on PEG, approximately 40 kDa PEG, and a defined peptide sequence.
References
- U.S. Food and Drug Administration. (2021). Empaveli prescribing information: Pegcetacoplan injection.
- U.S. Food and Drug Administration. (2023). Syfovre prescribing information: Pegcetacoplan injection.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
- U.S. Code. (2024). 21 U.S.C. § 355: New drugs.
- Apellis Pharmaceuticals, Inc. (2024). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934.
- U.S. Food and Drug Administration. (2024). Applications covered by Section 505(b)(2).
- United States Patent and Trademark Office. (2018). U.S. Patent No. 10,035,822: Long-acting compstatin analogs.
