Drugs coming off patent: patents, generics, FTO formulation, manufacturers...

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Lilly	DELTALIN	ergocalciferol	CAPSULE;ORAL	080884-001	Approved Prior to Jan 1, 1982		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Esjay Pharma	DRISDOL	ergocalciferol	CAPSULE;ORAL	003444-001	Approved Prior to Jan 1, 1982	AA	RX	Yes	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Chartwell Rx	ERGOCALCIFEROL	ergocalciferol	CAPSULE;ORAL	040833-001	May 20, 2009	AA	RX	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Onesource Specialty	ERGOCALCIFEROL	ergocalciferol	CAPSULE;ORAL	090455-001	Aug 3, 2010	AA	RX	No	Yes	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Exclusivity Expiration

Last updated: July 8, 2026

Executive summary

Ergocalciferol (vitamin D2) is a mature, widely generified active ingredient with limited patent-driven protection in the US. Investment upside is primarily driven by (1) formulation differentiation (strengths, dosing convenience, taste/matrix for oral and pediatric products), (2) route innovation (oral vs. injection, if applicable in a specific portfolio), (3) payer and distribution execution for branded label claims, and (4) contract manufacturing scale economics. The risk profile is dominated by rapid generic entry once any relevant listed exclusivity or formulation IP expires, and by regulatory reliance on established vitamin D bioavailability and labeling frameworks rather than high clinical-innovation barriers.

What is ergocalciferol (vitamin D2) and what indications drive market value?

Ergocalciferol (vitamin D2) is used to prevent and treat vitamin D deficiency and related disorders of calcium metabolism. In commercial practice, it typically sits in the broader “vitamin D” therapeutic class alongside cholecalciferol (vitamin D3) products and combination calcium-vitamin D regimens.

Core commercial demand drivers

Chronic deficiency treatment across outpatient settings
Maintenance dosing to prevent recurrence of deficiency
Indication-specific label language that can support reimbursement differentiation
Segment expansion via pediatric and geriatric dosing formats

Key competitive substitutability

High cross-substitution between vitamin D2 and vitamin D3 on a therapeutic outcomes basis in many formularies
Low switching cost for prescribers once generic availability is established

What patents protect ergocalciferol in the US and where is IP most likely to matter?

Direct API patent coverage is typically thin. For ergocalciferol itself, industry structures generally show that active-ingredient molecules are long out of patent term, leaving most enforceable rights concentrated in secondary inventions:

Specific formulation compositions (excipients, matrices)
Manufacturing processes (granulation, stabilization, particle size)
Stability enhancements for shelf-life performance
Device or administration system claims (if tied to a product presentation)
Method-of-use claims tied to dosing regimens or patient subsets, where available

Practical investment conclusion

Any investable exclusivity is likely product-level (Rx strength, formulation, or manufacturing method), not molecule-level.
Patent estate strength should be assessed by Orange Book listings and any ongoing Hatch-Waxman litigation. Without those, the default assumption is high generic erodibility.

What is the Orange Book status of ergocalciferol products and what does it imply for exclusivity?

In the US, exclusivity and listed patents for ergocalciferol are determined at the NDC-product level in FDA’s Orange Book. Because ergocalciferol is largely marketed as an established active ingredient, many products are present with expired or non-actionable patent listings, leaving:

Few remaining listed patents with enforceable remaining term
Generic competition as the baseline

Featured snippet answer Orange Book exclusivity for ergocalciferol usually provides limited time-protected revenue. The main protection window comes from whichever product-specific patents or exclusivities are still listed for the specific NDC/strength/formulation.

When does ergocalciferol lose exclusivity in the US and how should investors map timelines?

Investment timelines should be anchored to two layers:

Listed patent expiration (including formulation and method-of-use patents)
Exclusivity expiration (for specific product approvals, if any)

Because ergocalciferol is generally not a “new molecular entity” investment target, the most relevant scenario is whether any specific portfolio NDC has:

Active listed patents with meaningful remaining term, or
Active exclusivity attached to a particular NDA or 505(b)(2) approval

Timeline mapping framework

Pull patent-by-NDC listing
Identify earliest paragraph IV and first-to-file events among challengers
Model launch date as the later of patent expiry and any exclusivity expiry, adjusted for any litigation stay/settlement outcomes

What generic entry risks exist for ergocalciferol and how fast can prices erode?

High generic readiness is the default for ergocalciferol. Key entry risks:

Multiple ANDA candidates once patents are cleared
Early generic substitution once labeling is unchanged or deemed bioequivalent
Payer switching after acquisition of competitive inventory

Price and margin expectations

For commodity vitamin D2, gross-to-net compression is typically driven more by contracting and channel dynamics than by differentiated clinical positioning
Margin protection tends to rely on either: (a) formulation claims that sustain a higher reimbursed price, or (b) supply-chain scale and customer lock-in

Which companies are challenging ergocalciferol via Paragraph IV and what settlements typically do?

For investment diligence, the actionable dataset is:

ANDA filings with Paragraph IV certifications tied to Orange Book patents
Federal district court dockets showing infringement allegations
Settlement agreements that include “launch date” covenants

Investment implication

If there is no active litigation tied to a specific product’s listed patents, investors should assume generic entry proceeds at patent expiry with limited delay.
If litigation exists, the expected economic outcome depends on the settlement structure (carve-outs, delayed launch, authorized generic clauses).

What formulation patents and dosing-form rights can protect ergocalciferol revenue?

Where IP can persist, it usually does through “product engineering”:

Common formulation IP themes

Stabilization of ergocalciferol to reduce degradation and improve potency uniformity
Control of dissolution rate to improve onset consistency
Taste-masking and pediatric usability
Uniformity improvements for small-dose measurements
Container closure systems that reduce oxidation risk

Investor screening criteria

Claims tied to the actual dosage form and excipient system used in commercial manufacturing
Claims with remaining term beyond current projected generic launch dates
Evidence that the formulation is required to practice the patent (not easily designed around)

How does ergocalciferol compare with cholecalciferol (vitamin D3) in commercial and IP terms?

Commercial substitution is the main competitive axis.

Both are used for vitamin D repletion.
Many formularies prefer one or provide parity, and switching can be driven by brand trust, dose convenience, and contracting.

IP and litigation landscape comparison

Both are “old actives,” so patent leverage typically comes from formulation, combination products, and route-specific rights.
D3 products sometimes have more branded momentum depending on market history and which dosage forms were developed later, but the investment baseline remains generic-heavy.

What is the FDA regulatory pathway for ergocalciferol generics and 505(b)(2) products?

Typical routes

ANDA for generic equivalents using bioequivalence standards
505(b)(2) if an applicant relies on existing data for some elements and adds new elements (often formulation or labeling)

Investor diligence focus

Whether an NDA or 505(b)(2) approval created any remaining exclusivity
Whether generics can use listed patents to justify design-around or certification strategies
Whether any risk-based clinical bridging or labeling specificity affects entry timing

How strong is the patent estate for ergocalciferol: what matters most for litigation and licensing?

With ergocalciferol, “strong patent estate” typically means:

Remaining claims covering the marketed dosage form and manufacturing method
Enforceable, non-obvious claim breadth with clear infringement theory
Patent holder willingness to license, defend, or settle to protect revenue

Licensing economics

Licensing is more likely to be tied to formulation know-how and manufacturing IP than to the active itself.
For investors, deal value is driven by: (a) remaining term, (b) likelihood of non-design-around infringement, and (c) the number of potential generic competitors able to enter.

What manufacturing/IP barriers can slow down generic supply of ergocalciferol?

Barriers are mostly operational:

Ability to achieve stability and potency uniformity over shelf-life
Controlled particle characteristics and consistent dosing uniformity
Validation of excipient functionality and container closure performance
Batch consistency at scale

Investment lens

If a company controls validated manufacturing methods and has enforceable manufacturing-process claims, entry delays can extend.
Without strong enforceable rights, barriers still matter but they usually do not prevent generic approval and launch, only influence timelines and initial quality reliability.

Revenue exposure: where would investors find defensible growth for ergocalciferol?

Given commodity characteristics, growth is most defensible when tied to:

Differentiated dosage forms (injectable vs oral, pediatric liquids, high-dose schedules)
Expanded label compliance and adherence support
Contract manufacturing relationships with long-term supply commitments
Combination products where vitamin D2 is embedded with other actives that hold distinct IP or clinical positioning

Commercial hotspots

Retail and PBM contracting for deficiency treatment
Institutional supply (hospitals, long-term care) where logistics reliability matters

Investment scenarios for ergocalciferol: how should a buyer underwrite risk?

Scenario A: Portfolio-focused brand/formulation protection

Underwrite based on product-specific remaining patent/exclusivity
Expect generic pressure to begin at or near earliest cleared listed patent expiry for each NDC/strength
Value driver is defense against design-around and supply continuity

Scenario B: Contract manufacturing or supply-chain consolidation

Underwrite based on scale, quality system strength, and ability to meet stability specs
IP matters mainly for manufacturing-method claims if enforceable
Revenue durability is tied to customer stickiness and pricing power via cost leadership

Scenario C: Licensing/settlement-driven protection

Underwrite from settlement outcomes if litigation is active or recently resolved for a specific NDC
Value comes from delayed entry and authorized production economics
Key risk is that settlements only delay, not prevent, generic competition

Scenario D: Pure API commodity exposure

Underwrite as a low-multiple, margin-sensitive commodity
Expect rapid share shifts and sustained gross-to-net pressure
Buyability depends on cost advantages and hedged supply contracts

Key due-diligence checklist investors should use for ergocalciferol

Orange Book listings by NDC/strength/form for each target product
Remaining term of listed patents and type (formulation, method-of-use, manufacturing)
Evidence of any Paragraph IV filings and the status of litigation/settlements
Exclusivity attached to any NDA/505(b)(2) that created the product
Substitution dynamics versus vitamin D3 and combination regimens at PBM/formulary level
Manufacturing stability validation and container closure robustness
Contracting history: rebates, access, and whether pricing is protected by formulary position

Key Takeaways

Ergocalciferol is a mature vitamin D2 active with limited molecule-level patent runway; investable protection is typically product-specific (formulation, method, manufacturing).
Orange Book status and any tied litigation outcomes are the primary determinants of exclusivity duration and generic entry timing.
Commercial upside depends on differentiation that survives generic substitution, or operational scale that sustains margins under heavy price competition.
Investment risk is dominated by rapid ANDA entry once patents/exclusivity clear; underwriting should anchor to NDC-specific patent expiry schedules and any settlement-enforced launch delays.

FAQs

1) What patents usually cover ergocalciferol besides the active ingredient itself?
Formulation compositions, excipient/matrix systems, stabilization methods, manufacturing processes, and sometimes dosing regimen claims.

2) How can an investor estimate the generic launch date for a specific ergocalciferol NDC?
Use Orange Book listed patents and exclusivity attached to that NDC, then adjust for any active Paragraph IV litigation or settlement launch dates.

3) Does switching from vitamin D2 to vitamin D3 affect payer coverage and commercialization of ergocalciferol?
Yes, typically through formulary preferences, rebate strategy, and dosing convenience, which can drive substitution even when clinical use overlaps.

4) What matters more for long-term margins: patent protection or manufacturing scale for ergocalciferol?
Manufacturing scale and cost leadership matter most when patent protection is thin; patent protection matters most when specific formulation or process rights remain enforceable.

5) Are combination calcium-vitamin D products a better IP platform than ergocalciferol alone?
Often yes, because combination products can carry distinct formulation and labeling differentiation; however, actual protection depends on the Orange Book listings for the specific combination NDC.

References

FDA. “Drugs@FDA: FDA Approved Drug Products.” US Food and Drug Administration. https://www.accessdata.fda.gov/scripts/cder/daf/
FDA. “Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations.” US Food and Drug Administration. https://www.orangebook.scripps.com/
FDA. “Hatch-Waxman: Paragraph IV Certifications and ANDA Litigation Framework.” US Food and Drug Administration. https://www.fda.gov/
FDA. “ANDA/BLA/505(b)(2) Regulatory Pathways.” US Food and Drug Administration. https://www.fda.gov/

US Patents:	0
Tradenames:	4
Applicants:	14
NDAs:	14

ergocalciferol - Profile

What are the generic drug sources for ergocalciferol and what is the scope of patent protection?

Summary for ergocalciferol

US Patents and Regulatory Information for ergocalciferol

ERGOCALCIFEROL Investment Scenario and Fundamentals Analysis: Patent/Exclusivity, FDA Status, Competitive Entry Risk, and Revenue Exposure