PHOSLO Drug Patent Profile

When do Phoslo patents expire, and when can generic versions of Phoslo launch?

Phoslo is a drug marketed by Fresenius Medcl Care and is included in two NDAs.

The generic ingredient in PHOSLO is calcium acetate. There are two hundred and eighty-two drug master file entries for this compound. Twenty-one suppliers are listed for this compound. Additional details are available on the calcium acetate profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Phoslo

A generic version of PHOSLO was approved as calcium acetate by HIKMA on February 26^th, 2008.

Summary for PHOSLO

US Patents:	0
Applicants:	1
NDAs:	2
Raw Ingredient (Bulk) Api Vendors:	44
Clinical Trials:	7
Patent Applications:	1,280
Drug Prices:	Drug price information for PHOSLO
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for PHOSLO
What excipients (inactive ingredients) are in PHOSLO?	PHOSLO excipients list
DailyMed Link:	PHOSLO at DailyMed

See drug prices for PHOSLO

See drug sales revenues for PHOSLO

Recent Clinical Trials for PHOSLO

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Amgen	N/A
Azienda Ospedaliera Sant'Anna	N/A
Genzyme, a Sanofi Company	Phase 4

See all PHOSLO clinical trials

US Patents and Regulatory Information for PHOSLO

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Fresenius Medcl Care	PHOSLO	calcium acetate	CAPSULE;ORAL	021160-001	Apr 2, 2001		DISCN	No	No
Fresenius Medcl Care	PHOSLO GELCAPS	calcium acetate	CAPSULE;ORAL	021160-003	Apr 2, 2001		DISCN	Yes	No
Fresenius Medcl Care	PHOSLO	calcium acetate	CAPSULE;ORAL	021160-002	Apr 2, 2001		DISCN	No	No
Fresenius Medcl Care	PHOSLO	calcium acetate	TABLET;ORAL	019976-001	Dec 10, 1990		DISCN	Yes	No

Expired US Patents for PHOSLO

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Fresenius Medcl Care	PHOSLO	calcium acetate	TABLET;ORAL	019976-001	Dec 10, 1990
Fresenius Medcl Care	PHOSLO	calcium acetate	CAPSULE;ORAL	021160-001	Apr 2, 2001
Fresenius Medcl Care	PHOSLO	calcium acetate	CAPSULE;ORAL	021160-002	Apr 2, 2001
Fresenius Medcl Care	PHOSLO	calcium acetate	CAPSULE;ORAL	021160-002	Apr 2, 2001

International Patents for PHOSLO

See the table below for patents covering PHOSLO around the world.

Country	Patent Number	Title	Estimated Expiration
Canada	1333884	FIXATEUR DE PHOSPHORE (PHOSPHOROUS BINDER)

Supplementary Protection Certificates for PHOSLO

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0247633	62/1997	Austria		PRODUCT NAME: ATORVASTATIN CALCIUM; NAT. REGISTRATION NO/DATE: 1-21926, 1-21927, 1-21928 19970411; FIRST REGISTRATION: GB PL 00018/0240 - PL 00018/0242 19961107
0720599	CR 2014 00050	Denmark		PRODUCT NAME: EZETIMIBE AND ATORVASTATIN OR PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF, INCLUDING ATORVASTATIN AS ATORVASTATIN CALCIUM TRIHYDRATE; REG. NO/DATE: DE/H/3895-3898/001-004/DC 20140910
0933372	PA2008006	Lithuania		PRODUCT NAME: FOSAMPRENAVIR CALCIUM; REGISTRATION NO/DATE: EU/1/04/282/001-002 20040712
0933372	PA2008006,C0933372	Lithuania		PRODUCT NAME: FOSAMPRENAVIR CALCIUM; REGISTRATION NO/DATE: EU/1/04/282/001-002 20040712
0933372	SPC/GB08/018	United Kingdom		PRODUCT NAME: FOSAMPRENAVIR CALCIUM: ((1S,2R)-3-(((4-AMINOPHENYL)SULFONYL)(2-METHYLPROPYL)AMINO)-1-(PHENYLMETHYL)-2(PHOSPHONOOXY)PROPYL)-CARBABAMIC ACID C-((3S)-TETRAHYDRO-3-FURANYL) ESTER CALCIUM SALT; REGISTERED: UK EU/1/04/282/001 20040712; UK EU/1/04/282/002 20040712
0521471	SPC/GB03/033	United Kingdom		PRODUCT NAME: ROSUVASTATIN OPTIONALLY IN THE FORM OF A NON-TOXIC PHARMACEUTICALLY ACCEPTABLE SALT, PARTICULARLY THE CALCIUM SALT.; REGISTERED: NL 26872 20021106; NL 26873 20021106; NL 26874 20021106; UK PL 17901/0201 20030321; UK PL 17901/0202 20030321; UK PL 17901/0203 20030321
0521471	C300125	Netherlands		PRODUCT NAME: ROSUVASTATINUM, DESGEWENST IN DE VORM VAN EEN NIET-TOXISCH FARMACEUTISCH AANVAARDBAAR ZOUT, IN HET BIJZONDER HET CALCIUMZOUT; REGISTRATION NO/DATE: RVG 26872 - RVG 26874 20021106

PHOSLO (calcium acetate) market dynamics and financial trajectory: exclusivity, competitive threats, and revenue outlook

Last updated: June 14, 2026

Executive summary

• PHOSLO is a brand of calcium acetate indicated to control serum phosphorus in dialysis patients with chronic kidney disease.
• The product’s market growth ceiling is set by (1) patient prevalence for end-stage kidney disease (ESKD), (2) payer and formulary positioning versus sevelamer and lanthanum, and (3) dosing convenience and tolerability.
• Financial trajectory is typically dominated by share shifts inside the oral phosphate binder class rather than patent-driven supply constraints, because calcium acetate is largely off-patent and exposed to generic competition in most major markets (U.S. emphasis where FDA/Orange Book logic is relevant).
• The key dynamic for PHOSLO specifically is brand versus generic substitution at the pharmacy counter, mediated by copay coverage, network tiering, and product-level contracting.

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What is PHOSLO and how is calcium acetate positioned in the phosphate binder market?

PHOSLO is an oral phosphate binder containing calcium acetate used in patients with CKD to reduce intestinal phosphate absorption. In practice, the brand competes within a crowded therapeutic class that includes:

• Non-calcium binders: sevelamer salts (carbonate/hydrochloride), lanthanum carbonate
• Calcium-based binders: calcium acetate (PHOSLO and generics), calcium carbonate (various generics)
• Iron-based binder (contextual growth driver outside the classic sevelamer/lanthanum set): sucroferric oxyhydroxide in certain geographies and cohorts (not a direct label substitute in many markets)

Featured snippet answer: PHOSLO (calcium acetate) is a calcium-based oral binder used to control hyperphosphatemia in dialysis CKD, and its economics are driven more by generic substitution and payer contracting than by brand exclusivity.

How clinicians typically choose among binders

Choice is usually driven by:

• Serum phosphorus targets
• Calcium load strategy (risk-benefit for hypercalcemia and vascular calcification)
• Pill burden and timing
• Gastrointestinal tolerability
• Formulary access and prior authorization

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How big is the phosphate binder market and what tailwinds support demand?

Demand tailwinds

• Persistent growth in dialysis and ESKD patient populations (U.S. and global).
• Ongoing chronicity of CKD supports long-duration therapy.

Structural headwinds

• Increasing preference for non-calcium binders in subpopulations to mitigate calcium-related concerns.
• Rising emphasis on value-based formularies and lower acquisition cost options.

Implication for PHOSLO: Even with stable class demand, calcium acetate brands face pricing pressure when payer tiers favor low-cost generics.

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What market dynamics drive PHOSLO sales: generics, payer tiers, and substitution?

PHOSLO’s sales trajectory is typically shaped by three overlapping forces.

1) Generic substitution at retail and through PBMs

• When calcium acetate generics are available with meaningful coverage, PHOSLO’s share depends heavily on:
  • Preferred status at PBMs
  • Copay design and rebate arrangements
  • Pharmacy claims data and formulary edits

Economic mechanism: Brand revenues fall as net pricing erodes and patients switch to generics, even if clinical use persists.

2) Contracting for dialysis units and integrated delivery networks

Dialysis care is often routed through procurement and formulary systems that can require:

• Clinical criteria for non-preferred products
• Prior authorization
• Step therapy

Economic mechanism: When PHOSLO is excluded or restricted, adoption slows quickly.

3) Patient-level switching sensitivity

• Binders are taken multiple times daily.
• Any tolerability advantage can maintain use even with higher cost, but cost and coverage usually dominate over time.

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When does PHOSLO lose exclusivity, and how does that affect revenue?

For calcium acetate brands such as PHOSLO, the practical exclusivity issue is generally not a long patent runway for the active ingredient. The revenue risk profile is instead tied to:

• Generic market entry timing for calcium acetate in relevant dosage forms
• Potential later-life patents (if any) that protect formulations or specific claims, and whether those are enforceable and commercially meaningful

Implication for financial trajectory: PHOSLO behaves like a mature brand under persistent generic competition, where growth is hard without niche formulary placement or differentiated access.

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What is the Orange Book status of PHOSLO and what patents are listed?

A complete Orange Book and patent-list mapping is required to state:

• Patent numbers
• Expiration dates
• Drug product codes and dosage forms
• Exclusivity codes
• Method-of-use or formulation protections

No Orange Book listing data is provided in the prompt, so a definitive status table cannot be produced.

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How strong is the patent estate for PHOSLO versus generic calcium acetate?

In mature small-molecule phosphate binder categories, the generic threat is typically driven by:

• Active ingredient maturity (calcium acetate)
• Short functional differentiation for “clinically equivalent” binder products
• Formulation or manufacturing details that may or may not translate into enforceable barriers

Business impact: Even where some secondary patents exist, generic penetration usually remains high if the core drug is non-proprietary and the formulary incentives favor cost.

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What generic entry risks exist for PHOSLO, including Paragraph IV challenges?

Paragraph IV risk analysis requires:

• Orange Book patent granularity
• Known ANDA filings and the paragraph IV certification history
• Settlement agreements, if any

No Orange Book or litigation detail is included in the prompt, so a definitive Paragraph IV timeline cannot be generated.

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What patent litigation affects phosphate binder brands like PHOSLO?

Patent litigation risk depends on:

• Whether the brand is actively asserting late-life formulation/process patents
• Whether it has a track record of enforcement against ANDA filers
• Whether the FDA litigation status is current

The prompt contains no PHOSLO-specific litigation docket information, so no accurate litigation summary can be provided.

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What formulations are protected for calcium acetate brands, and do those barriers matter commercially?

Formulation barriers can matter if they protect:

• Dosing regimens with improved tolerability
• Specific granulation/particle-size characteristics
• Stability, dissolution profile, or excipient system that affects phosphate binding kinetics

Commercial relevance depends on whether clinicians and payers perceive meaningful differences that overcome generic cost advantages. For mature phosphate binders, commercial differentiation is often limited, and formulation patents rarely prevent sustained generic share erosion.

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How do sevelamer, lanthanum, and calcium carbonate impact PHOSLO market share?

PHOSLO competes primarily on:

• Cost
• Pill burden
• Side effect profile and calcium/phosphorus management goals

Typical competitive pattern

• Sevelamer often wins when payers or clinicians prioritize avoiding calcium load.
• Lanthanum can win for adherence and dosing preferences but faces payer restrictions and cost.
• Calcium carbonate wins when low acquisition cost and availability dominate and when calcium strategy is clinically acceptable.

Implication for PHOSLO: PHOSLO’s competitive resilience is usually most stable in:

• Fully capitated or cost-sensitive settings that allow calcium-based binders
• Patients who tolerate calcium acetate well and remain on stable dosing

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What is the FDA regulatory status of PHOSLO, and how does it affect supply and competition?

A complete FDA status requires:

• Current labeling (indications, dosing, limitations)
• Approved dosage forms and strengths
• Supplement history that could indicate manufacturing changes or new labeling that alter usage

No FDA labeling or product dossier details are supplied in the prompt, so no regulator-grade status mapping is provided.

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What financial trajectory should investors expect for PHOSLO, given typical brand economics?

Without access to PHOSLO’s specific historical financial statements and unit sales in the prompt, the most defensible framework is class-typical brand behavior under generic pressure.

Expected revenue shape (typical mature binder brand under generic substitution)

• Peak then decline after generic entrants or tier exclusion
• Stabilization if the brand retains preferred positioning in some segments or maintains higher adherence
• Ongoing erosion when PBM formularies or dialysis procurement shift further to low-cost products

What drives net sales versus profit

• Net price declines are usually the first-order effect of generic competition.
• Gross margin can erode with rebate and discount structures demanded by payers.
• Operating leverage is limited unless volume stabilizes and manufacturing costs remain controlled.

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Which companies are most likely competing with PHOSLO in practice?

For calcium acetate phosphate binders, competition usually includes:

• Generic manufacturers supplying calcium acetate tablets/capsules
• Brand competitors across the binder class (sevelamer and lanthanum branded products)

A company-by-company ranking requires market-share, wholesaler, and claims datasets not provided in the prompt.

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What licensing and commercialization deals matter for phosphate binder brands?

Licensing and co-promotion deals can affect:

• Territory access
• PBM contracting leverage
• Manufacturing continuity

No deal database entries are provided in the prompt, so this cannot be quantified.

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Key takeaways

• PHOSLO’s market dynamics are primarily driven by generic substitution and payer contracting within the phosphate binder class rather than by long-running exclusivity.
• Demand is supported by chronic dialysis CKD prevalence, but share is determined by calcium strategy, tolerability, pill burden, and formulary economics.
• Financial trajectory for PHOSLO generally follows a mature brand under ongoing generic pressure: declining net pricing, periodic stabilization if coverage is retained, and continued erosion as formularies optimize for lower acquisition cost.
• A definitive exclusivity, Orange Book, Paragraph IV, and litigation timeline for PHOSLO requires drug-product specific listing and court/docket records not included in the prompt.

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FAQs

1. How do phosphate binder formularies in dialysis programs usually tier calcium acetate versus sevelamer and lanthanum?
2. What patient calcium-load risk factors increase the likelihood of switching from calcium acetate to non-calcium binders?
3. How does pill burden and dosing frequency change adherence for calcium acetate phosphate binders?
4. What PBM rebate structures typically accelerate brand erosion for off-patent phosphate binders?
5. How do net pricing and copay design interact to determine whether patients remain on PHOSLO or switch to generics?

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References

No sources are provided in the prompt, and no PHOSLO-specific Orange Book, FDA labeling, litigation, or financial statement citations are included.