Drugs in ATC Class C09XX

Up to Top Level ATC Classes

Up to C - Cardiovascular system

Up to C09 - AGENTS ACTING ON THE RENIN-ANGIOTENSIN SYSTEM

Up to C09X - OTHER AGENTS ACTING ON THE RENIN-ANGIOTENSIN SYSTEM

Drugs in ATC Class: C09XX - Other agents acting on the renin-angiotensin system

Tradename	Generic Name
FILSPARI	sparsentan

Market dynamics and patent landscape for ATC Class C09XX (Other agents acting on the renin-angiotensin system)

Last updated: July 21, 2026

ATC C09XX is a broad “other” bucket for renin-angiotensin system (RAS) agents that sit outside mainstream ACE inhibitors, ARBs, and direct renin inhibitors. Patent and market dynamics are dominated by (1) the specific drug assets that manufacturers have listed under C09XX in each country’s ATC system, and (2) whether those assets are protected by composition/formulation patents, method-of-use patents, and (3) whether FDA/EMA approvals are tied to branded exclusivities and subsequent generics/biosimilars.

This page maps the commercial logic and exclusivity drivers that govern C09XX competition, then translates those dynamics into an IP-and-litigation checklist that you can use to size generic entry risk by asset class: replacement RAS peptide pathways, next-generation RAS modulators, and adjunct RAS-inhibiting combinations.

Which drugs are in ATC C09XX, and how does that shape competition?

Featured snippet answer: C09XX functions as a heterogeneous category; competition and patent strength vary sharply by the exact active ingredient(s) assigned to it in each market.

C09XX is not a single molecule. It is a classification label used by regulators and payers to group “other agents acting on the renin-angiotensin system.” As a result, the market is a portfolio of different mechanisms rather than one competitive set.

What market segmentation looks like under C09XX

In practice, the competitive structure typically splits along the same fault lines seen in other ATC “other” buckets:

• Indication segmentation: hypertension, heart failure, post-MI risk reduction, renal protection, and less commonly RAS-related endocrine indications.
• Delivery segmentation: oral small molecules versus peptide/biologic-adjacent therapies.
• Regulatory segmentation: branded originals with later generic waves versus assets with limited generic substitutability.

How classification breadth impacts patent analysis

For IP work, breadth is a risk factor because:

• Competitors may not map cleanly by ATC label.
• Patent estates can be mechanism-specific even when commercial positioning looks similar.
• Orange Book style exclusivity and jurisdictional enforcement depend on the exact NDA/MA number tied to the active ingredient, not the ATC code.

What patents protect renin-angiotensin “other” agents (C09XX) in practice?

Featured snippet answer: Patent coverage for C09XX agents usually concentrates in composition claims, polymorph/solid-state claims, formulation and release claims, and method-of-use claims for specific patient populations or dosing regimens.

Because C09XX aggregates disparate mechanisms, the patent architecture is best analyzed by patent layer.

Typical patent layers you should expect in C09XX

1. Active ingredient composition (process and product)

   • Core compound claims
   • Alternative salts
   • Alternative polymorphs or amorphous forms (if solid-state is relevant)

2. Formulation patents

   • Tablet/capsule compositions
   • Film coating or controlled-release layers
   • Stabilizers and excipients tied to stability and bioavailability

3. Method-of-use patents

   • Indication-specific claims (e.g., hypertension subtypes, resistant hypertension)
   • Dosing schedules (titration protocols)
   • Combination regimens with other antihypertensives

4. Manufacturing and intermediate claims

   • Protected synthetic routes and key intermediates
   • Scale-up and impurity control approaches

5. Regulatory exclusivity (jurisdictional overlay)

   • Data exclusivity and marketing exclusivity in the U.S. for NDA/NCE
   • Supplementary protection certificates (SPCs) in the EU for qualifying products
   • Patent term extensions where available

How to translate patent layers into generic entry barriers

• If the core compound is off-patent, generic risk often depends on whether formulation or method-of-use patents remain.
• If only the compound is off-patent but dosing regimens are still protected, the generic may launch but face label carve-outs and payer substitution limits.
• If solid-state forms are patented, you may see “authorized generic” strategies that comply with freedom-to-operate while limiting enforcement exposure.

When does patent exclusivity end for C09XX agents, and what drives the endgame?

Featured snippet answer: The end of exclusivity for C09XX assets depends on the specific active ingredient’s last-proper combination of (1) patent expiry, (2) regulatory data/marketing exclusivity, and (3) SPC or patent term extension effects.

For RAS agents in C09XX, the timeline is often staggered:

• The first wave ends with the earliest core compound expiry.
• A second wave comes from formulation and method-of-use claims.
• A third wave comes from SPCs and jurisdictional patent term adjustments.

What you should model for each C09XX asset

A practical endgame model includes:

• Earliest primary compound expiration
• Last composition/formulation expiration
• Last method-of-use expiration
• SPC “effective” life (EU)
• Any patent term extension (if applicable)
• Regulatory exclusivity window
  • U.S.: data exclusivity and any marketing exclusivity tied to the NDA
  • EU/UK: data protection and SPC extensions

Endgame patterns in RAS “other” assets

Common patterns include:

• Method-of-use claims surviving beyond composition expiry through patient-response or dosing-specific language.
• Formulation patents persisting due to later “line extensions” tied to improved stability or bioavailability.
• Combination claims if the C09XX asset is paired with other antihypertensives (risk shifts to label compatibility and carve-out design).

What is the Orange Book status of C09XX agents, and how does that determine Paragraph IV risk?

Featured snippet answer: Orange Book risk for C09XX depends on whether the specific active ingredient is listed with unexpired patents and whether ANDA filers can carve around method-of-use and formulation listings.

C09XX is not a category you can query directly in the U.S. regulatory system. Orange Book listings attach to a drug product and active ingredient(s) tied to an NDA. So the relevant question is: which C09XX active ingredients have ANDA pathways.

How to read Orange Book listings for “other” RAS agents

• Identify unexpired patents linked to the drug product.
• Map each patent type to potential ANDA strategy:
  • If composition/formulation patents are listed, generic need either a design-around or non-infringing approach.
  • If method-of-use patents are listed, generic may launch with label carve-outs if allowed by the FDA approval pathway and the patent scope.

Paragraph IV “launch timing” logic

Paragraph IV is usually the timing lever when:

• The core composition is expired.
• Remaining listed patents are weaker or design-around friendly.
• A first ANDA filer can accept litigation risk to secure earlier market share.

How many patents cover C09XX agents, and which jurisdictions carry the biggest enforcement weight?

Featured snippet answer: Enforcement and litigation exposure for C09XX assets concentrate in U.S. and EU markets where brand companies build dense patent portfolios across composition, formulation, and SPC-extended claims.

Jurisdictional enforcement pattern

• United States: Orange Book-listed patents determine ANDA/Paragraph IV risk; litigation targets FDA approval timing.
• European Union/UK: SPCs and national validations determine whether “one more year” type delays materialize.
• Other markets: local patent availability and enforcement track record decide whether generic entry is delayed or immediate.

Patent count is less predictive than claim type

For RAS “other” agents:

• A high patent count does not always mean long exclusivity if patents are concentrated in early layers.
• A low count can still block entry if the remaining claims are method-of-use or solid-state form patents with narrow design-around options.

Which companies dominate the C09XX renin-angiotensin “other” space, and what do their IP strategies look like?

Featured snippet answer: Dominant players in C09XX typically use late-cycle lifecycle management, including formulation IP and method-of-use expansions, to sustain branded label value and delay generic substitution.

What the leading brand strategy usually includes

• Patent estate expansion around:
  • improved stability or tolerability formulations
  • specific patient subpopulations
  • combination therapy positioning
• Use of SPC where eligible (EU)
• Litigation selection:
  • prioritize jurisdictions with enforceable patent density
  • target ANDA challengers that threaten the full label

What generic challengers typically do

• File early ANDAs with carve-out labels to reduce infringement exposure.
• Pursue design-around for formulation if composition has expired but excipient/release mechanics remain protected.
• Choose settlement-friendly jurisdictions where expected damages and injunctive outcomes are more predictable.

What formulation patents are common for RAS “other” agents, and what design-arounds work?

Featured snippet answer: C09XX formulation patents often protect solid-state forms and release/stability parameters; workable design-arounds typically focus on different polymorphs, different release mechanisms, and non-infringing excipient systems.

Formulation claim patterns to watch

• Polymorph/amorphous form claims
• Particle size distribution and milling process tied to dissolution
• Coating systems and moisture uptake controls
• Controlled release matrices
• Bioequivalence-sensitive dissolution profiles

Design-around “hot spots”

• Changing solid-state form may avoid infringing “polymorph specific” claims but can trigger other patents.
• Altering dissolution profile can break bioequivalence unless the FDA requirements are satisfied, increasing development cost and risk.
• Switching excipients can be blocked by narrow composition claims.

What method-of-use patents for C09XX agents delay generics?

Featured snippet answer: Method-of-use patents delay generics when they tie dosing regimens to measurable clinical outcomes or specific patient populations in ways that are hard to carve out without changing the label.

Common method-of-use structures

• Claims for hypertension subsets:
  • resistant hypertension
  • specific comorbidity-defined populations
• Claims for clinical endpoints:
  • reduction in hospitalization
  • renal progression markers
• Claims for titration and dosing sequences

Label carve-out feasibility

• High feasibility when claims are clearly separable by indication.
• Low feasibility when claims are broad across patient subsets and endpoints, leaving little label room for a generic.

What patent litigation affects C09XX agents, and how do settlements change entry risk?

Featured snippet answer: Litigation typically affects C09XX via FDA approval timing (U.S.) and via injunctive leverage (EU), while settlements often convert launch timing into delayed entry with royalty or shared-risk structures.

Litigation and settlement mechanics that matter

• In the U.S., settlements usually function as:
  • agreed launch dates
  • stipulated injunction relief
  • license terms tied to continued commercialization
• In the EU, settlements often resolve:
  • validity and infringement fights around SPC and national equivalents
  • carve-out labels and prescription restrictions

What to look for in settlement-driven landscapes

• Whether the settlement locks in a “no-launch until” date that is tied to a specific patent expiry.
• Whether it restricts generic label claims in ways that preserve brand reimbursement.
• Whether it allows co-marketing or “authorized generic” channel impacts.

How does C09XX compare with ACE inhibitors, ARBs, and direct renin inhibitors on exclusivity?

Featured snippet answer: The exclusivity profile of C09XX is often less uniform than ACE/ARB classes because the category includes fewer high-volume assets and more niche mechanisms with smaller generic ecosystems.

Practical comparison

• ACE/ARB categories have long generic histories and dense ANDA ecosystems, compressing brand time-to-generic once primary patents fall.
• C09XX “other” assets may face fewer generic challengers, but brand companies can still extend exclusivity through targeted method-of-use and formulation estates.

What generic entry risks exist for C09XX agents?

Featured snippet answer: Generic entry risk is driven by (1) whether any Orange Book-listed patents remain unexpired, (2) whether unexpired patents are design-aroundable, and (3) whether method-of-use coverage allows label carve-outs.

Generic entry risk scoring framework (IP-only)

For each C09XX active ingredient, assess:

• Patent layer remaining (compound vs formulation vs method-of-use)
• Jurisdictional enforceability strength (SPC availability and national density)
• Litigation history with ANDA challengers
• Likelihood of successful carve-out

Commercial risk mapping

• High brand exposure persists when:
  • method-of-use claims cover core prescriber practice
  • formulation patents affect FDA-equivalence or require additional bridging studies
• Lower brand exposure when:
  • remaining claims are narrow and label carve-outs are straightforward
  • competitor’s business case relies on rapid switching with minimal clinical friction

Key takeaways

• ATC C09XX is a heterogeneous grouping; market and patent dynamics must be analyzed by exact active ingredient, not by the code.
• For RAS “other” agents, patent estates most often extend exclusivity through formulation (solid-state/release) and method-of-use (label/dosing) layers even after primary compound expiry.
• Generic and ANDA timing hinges on Orange Book unexpired patents and whether method-of-use/formulation coverage permits label carve-outs or design-arounds.
• EU enforcement can extend effective exclusivity via SPCs and national validations, shifting the litigation calendar and settlement leverage.
• Competitive positioning depends on whether brand value is tied to label scope versus drug substitution tolerance.

FAQs

1. Which ATC C09XX active ingredients have U.S. ANDA pathways and Orange Book-listed patents that drive Paragraph IV timing?
2. How do method-of-use claim scopes in RAS “other” agents translate into label carve-out options for generics?
3. What formulation attributes most frequently create infringement risk for RAS “other” agent generics (polymorph, dissolution, excipients)?
4. Do SPCs materially change the exclusivity end dates for C09XX agents in EU markets compared with U.S. patent expiry?
5. What settlement terms in RAS patent litigation most strongly correlate with delayed generic launch in C09XX assets?

References

1. European Medicines Agency (EMA). European patent and supplementary protection certificate framework.
2. U.S. Food and Drug Administration (FDA). Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations.
3. World Health Organization Collaborating Centre for Drug Statistics Methodology. ATC classification system.