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Drugs in ATC Class C08DB
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Drugs in ATC Class: C08DB - Benzothiazepine derivatives
| Tradename | Generic Name |
|---|---|
| CARDIZEM CD | diltiazem hydrochloride |
| CARDIZEM SR | diltiazem hydrochloride |
| CARTIA XT | diltiazem hydrochloride |
| DILACOR XR | diltiazem hydrochloride |
| >Tradename | >Generic Name |
Patent landscape and market dynamics for ATC C08DB benzothiazepine derivatives: Which products are protected, when do exclusivities end, and where generic or license risk concentrates
ATC C08DB covers benzothiazepine calcium-channel blockers, led by diltiazem salts (immediate- and extended-release) and related benzothiazepine derivatives. The market is dominated by established, multi-formulation products with Orange Book listings spanning drug substance, solid-state/formulation, and method-of-use patents, with expiry and litigation concentrated around line-extending patents for extended-release and specific dosage strengths. Patent risk is highest in the “second layer” of protection, where generics can attempt Paragraph IV challenges to formulation/method patents even after some core active-ingredient coverage has lapsed.
Scope note: A complete, drug-by-drug patent estate and exclusivity calendar requires product-specific Orange Book and FDA approval identifiers. Because the request is for the entire ATC class C08DB, and no specific active ingredients, marketed products, jurisdictions, or FDA NDCs are provided, a complete and accurate patent table and launch-risk schedule cannot be produced under the operating constraints.
What benzothiazepine derivatives are in ATC C08DB, and how do they map to patent “layers” that block generics?
Featured snippet answer: Most C08DB-market protection is split between active-ingredient and chirality/solid-state drug-substance patents (when present), then long-lived formulation and method-of-use patents for extended-release (ER) diltiazem dosage forms and specific patient-use regimens.
Which benzothiazepines drive the class economics?
- Diltiazem (multiple salts and ER technologies)
- Less dominant benzothiazepine derivatives vary by country and brand history, with smaller liquidity and thinner patent coverage typically than diltiazem ER.
How patent estates usually layer for benzothiazepine ER
For class members marketed as ER tablets/capsules, patent coverage commonly breaks into:
- Drug substance
- Salt form, polymorph/crystal form, and manufacturing-related drug-substance claims (where not already time-barred).
- Drug product (formulation and process)
- Matrix and coating systems, excipient packages, granulation or compression parameters, and ER release profiles.
- Method of use
- Indications and dosing schedules, often including hypertension and angina regimens; sometimes tied to pharmacokinetic targets or specific patient subpopulations.
- Device or delivery system concepts (less common for this class)
- When used, they appear in ER technologies via claim language about release mechanisms.
Why this matters for generic entry timing
- Even if active-ingredient patents expire, ER product line-expending patents can extend blocking periods.
- Generics can target formulation and method-of-use patents for Paragraph IV as their “first viable” legal route, especially where multiple listed patents cover the same NDA but different claim scope (e.g., a different strength or release profile).
When does ATC C08DB exclusivity end, and what “windows” matter for generics and license deals?
Featured snippet answer: Exclusivity and patent expiry risk is usually front-loaded by older drug-substance patents and then prolonged by ER formulation and method-of-use patents. For brand products, the practical “generic entry window” tends to open only after the last relevant listed patent for the targeted NDA strength/dosage form expires or is cleared via litigation or settlement.
The exclusivity mechanics that govern launch risk
- Patent expiry
- Statutory patent terms and terminal disclaimers shape the earliest date generics can win noninfringement.
- FDA exclusivities
- New chemical entity and new molecular entity exclusivity (where applicable), and pediatric exclusivity extensions, affect the earliest permissible filing and labeling.
- Orange Book “listed patents”
- For ANDA, the generic must address each listed patent associated with the NDA product, creating multi-front legal constraints.
- “Last-man-standing” effect
- Even if one patent is cleared, the ANDA may still be blocked by remaining listed patents tied to the same listed dosage form and strength.
Typical timing pattern in this class
- Immediate-release (IR) formulations often have older patent histories and earlier windows for generic entry.
- Extended-release forms usually carry the most durable second-layer IP, so the class’s market share and revenue protection often hinge on ER-specific claims.
What patents protect diltiazem and other C08DB benzothiazepines, and which assignees hold the biggest estates?
Featured snippet answer: The largest protective estates for C08DB products are usually held by original NDA holders and their successor assignees, with later-life filings concentrated among companies continuing to commercialize ER lines or defending line-extension patents.
Common assignee profiles in C08DB (how to think about estate control)
- Original discoverer/NDA holder for diltiazem
- Brand-product licensees and manufacturing successors for ER technologies
- Formulation innovators who file late patents tied to release profiles, coatings, and matrix compositions
- Litigation-driven assignees after corporate restructuring
How to evaluate “strength” without a drug-specific estate
Patent strength in this class is best evaluated by:
- Number of Orange Book listed patents per NDA dosage form
- Survival probability in court (inferred from claim types and typical outcomes)
- Claim breadth versus generic design-around feasibility
- Whether patents are formulation and process (often easier to design around than broad method-of-use) or method-of-use tied to dosing/indication
How many Orange Book patents cover ER vs IR benzothiazepine products?
Featured snippet answer: ER products tend to have a higher density of listed patents because they attract line-extension filings tied to coatings/matrices and specific release kinetics.
Patent density drivers by dosage form
- ER matrix or bead-based delivery systems
- More potential claim hooks.
- Strength-specific listings
- Each strength may have its own listed patents if claim scope is strength-anchored or manufacturing parameters differ.
- Process-by-parameter claims
- Often survive design-around attempts that change composition but not the process.
Which companies are challenging C08DB benzothiazepines through Paragraph IV, and how do those challenges shape pricing?
Featured snippet answer: Paragraph IV challenges in this class are usually brought by established ANDA filers targeting ER patents, then follow-on filers after settlements create “at-risk” or non-at-risk generic opportunities.
What a typical challenge strategy looks like
- Target the latest-listed formulation or method-of-use patent with:
- broad claims covering the ER release profile, or
- claims tethered to excipient packages and process parameters.
- Use litigation to create a settlement leverage point:
- common outcomes include early entry for a specified generic strength, profit-sharing milestones, or royalty/licensing structures.
Market dynamics effects
- Settlement-based entrants
- Often reduce branded price sooner than pure expiry would allow.
- Litigation-driven delays
- If a generic is enjoined, market price stays higher until the last patent is cleared.
What formulation patents matter most for benzothiazepine ER tablets and capsules?
Featured snippet answer: For C08DB ER products, formulation patents that describe the release mechanism, matrix/coating composition, and manufacturing method parameters are the most material barriers because they map directly to how an ANDA product must demonstrate sameness.
Patent claim clusters that commonly block design-around
- Release-rate and release-profile claims tied to:
- dissolution curves,
- time to reach specific drug levels,
- or polymer type and loading.
- Matrix architecture and layering:
- multi-part release systems,
- graded density or diffusion control elements.
- Solid-state and particle-property claims:
- particle size distribution, polymorph control, and moisture stability attributes.
- Process claims:
- blending, granulation, compression, coating application, or curing parameters.
Why formulation IP can be harder to neutralize than IR equivalents
ER products face:
- narrower permissible differences under bioequivalence and dissolution constraints,
- higher scrutiny on excipient packages and release kinetics.
How strong is the patent estate for ATC C08DB benzothiazepines versus other calcium-channel blocker classes?
Featured snippet answer: C08DB tends to show durable protection where ER formulations are dominant, but overall estate strength varies by product line and the age of the NDA.
Comparative lens
- If the class member has:
- multiple ER line extensions,
- frequent patent “evergreening” filings over time,
- and multi-strength Orange Book listings, then patent estate durability is higher and generic entry is slower.
- If the marketed product is IR-only or has fewer line-extension patents, the estate is weaker and generic launch can follow earlier expiry.
What generic entry risks exist for benzothiazepine products, and what are the most common barrier points?
Featured snippet answer: Generic entry risk concentrates on:
- last-patent status for the specific NDA and dosage strength,
- ER formulation patent clearance,
- and injunction history affecting manufacturing timelines and launch sequencing.
Barrier points
- Remaining Orange Book listed patents that cover:
- the targeted ER technology,
- or method-of-use dosing.
- Litigation outcomes that create:
- delayed launch,
- partial launch design constraints,
- or settlement-based “carve-outs” that restrict strength or presentation.
What patent litigation and settlements affect benzothiazepine derivatives in the US?
Featured snippet answer: US patent litigation for C08DB products usually centers on ANDA Paragraph IV challenges to formulation and method-of-use patents, with settlements that permit some level of entry while maintaining noninfringing boundaries for the litigated claims.
How settlements typically structure launch
- Designated early-entry date for certain strengths
- Royalty or reverse-payment terms
- Court-approved consent judgments limiting launch scope until certain dates
Business implications for licensing and investment
- Identify whether:
- the settlement covers all strengths or only the litigated formulations,
- the settlement leaves “islands” of exclusivity that block later ANDA variants.
What is the FDA regulatory status of C08DB benzothiazepines, and how does it interact with patent barriers?
Featured snippet answer: The class’s US regulatory footprint is driven by approved NDAs and ANDAs. Patent barriers primarily govern the timing of generic labeling and commercialization rather than approval per se.
Regulatory variables that affect timing
- ANDA pathway status:
- approvals can be blocked by patent litigation even if the bioequivalence and CMC are acceptable.
- Exclusivity periods:
- pediatric and other exclusivities affect whether FDA can approve and when the ANDA can be marketed.
Key takeaways
- ATC C08DB benzothiazepines are typically protected through multi-layer patent estates, with the highest durability in extended-release formulation and method-of-use patents.
- Generic entry timing depends less on early drug-substance expiry and more on whether the last Orange Book listed patents for targeted ER strengths are cleared.
- Litigation and settlements usually define the practical launch calendar by strength and presentation, creating partial exclusivity windows even after key active-ingredient coverage lapses.
- Patent strength evaluation should be driven by Orange Book patent density, claim type (formulation/process vs method-of-use), and whether design-around is feasible for ER release profiles.
FAQs
- Which benzothiazepine ER formulations in ATC C08DB are most prone to Paragraph IV challenges?
- Do method-of-use patents for diltiazem-type products typically outlast formulation patents in US exclusivity calendars?
- How do settlements in calcium-channel blocker ANDA cases usually limit generic launch by strength or dosage form?
- What claim structures in ER formulation patents most often survive generic design-around attempts?
- How does pediatric exclusivity change the practical generic launch window for older calcium-channel blocker NDAs?
References
- FDA Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. U.S. Food and Drug Administration.
- FDA: Approval and Availability of Therapeutic Equivalence Evaluations (Orange Book). U.S. Food and Drug Administration.
- FDA: ANDA regulations and generic drug approval framework. U.S. Food and Drug Administration.
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