Invalidity dossier
US 6576665
Encapsulated calcium acetate caplet and a method for inhibiting gastrointestinal phosphorous absorption
Current assignee: Fresenius Medical Care Holdings Inc
Added 9/23/2026, 12:50:06 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US 6,576,665 B2
Title: Encapsulated calcium acetate caplet and a method for inhibiting gastrointestinal phosphorous absorption
Patent number / application: US 6,576,665 B2; Application US09/824,949
Inventors: Edmund V. Dennett, Jr.; Robert M. Raleigh, Jr.; Bruce H. Aronson
Original assignee: Braintree Laboratories Inc. (later assignments to NABI Biopharmaceuticals, Fresenius USA Manufacturing, Inc., and Fresenius Medical Care Holdings, Inc. appear in the source as recorded reassignments.)
Key dates: Priority/filing 2001-04-03; publication 2003-06-10; status listed as expired – lifetime, adjusted expiration 2021-07-30.
Purpose: The invention relates to oral pharmaceutical compositions, specifically an encapsulated calcium acetate caplet, and to a method for binding and inhibiting gastrointestinal absorption of phosphorous. It is directed to managing or preventing hyperphosphatemia, particularly in chronic renal failure and end-stage renal disease, by binding dietary phosphorus in the gastrointestinal tract to form insoluble, unabsorbable phosphate compounds. The source notes calcium acetate is most effective when administered close in time to food consumption.
Plain-language scope: According to the supplied text, the composition includes a quantity of calcium acetate, having a specific bulk density range, sufficient to bind phosphorous in the gastrointestinal tract. The patent also describes a method for binding phosphorous, reducing serum phosphate levels, and treating or preventing hyperphosphatemia and other conditions where phosphorus excretion is impaired. The source discusses dosage size, palatability, bulk density variability, and USP standards (USP #24, test #711 for calcium acetate tablet dissolution), and frames the goal as an encapsulated caplet that seals taste and compresses medication to reduce dosage volume.
Source: https://patents.google.com/patent/US6576665/en
What the excerpt does not establish: The supplied text is explicitly marked as an excerpt with omitted content. It does not provide the full claims, the specific bulk density range or numeric limits, formulation examples, or complete method steps. It also does not establish litigation outcomes, ownership validity, enforceability, or prior-art analysis, and it explicitly disclaims legal conclusions about status or assignee accuracy.
Include available title, assignee, dates, purpose and plain-language scope.
Generated 10/1/2026, 9:53:28 PM
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Litigation summary
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Proceedings on file (0)
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No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
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Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.