In short
Calcium acetate anhydrous is a calcium-containing phosphate binder used to control high blood phosphate levels (hyperphosphatemia) in people with end-stage kidney disease. It is an authorised medicine available as capsules. One registered clinical trial (NCT05680818) lists it as part of the standard-of-care comparison arm in a Phase 3 study of encaleret for autosomal dominant hypocalcemia type 1 (ADH1).
Calcium acetate anhydrous is a calcium-containing medicine used as a phosphate binder in people with advanced kidney disease. It is an authorised medicine, available as capsules containing 667 mg of calcium acetate anhydrous, equivalent to 169 mg (8.45 mEq) of calcium. The substance is also known as calcium acetate, calcium diacetate, and acetic acid calcium salt. In the EU Clinical Trials Information System, it appears as a comparator in a Phase 3 trial for autosomal dominant hypocalcemia type 1 (ADH1).
Key points
- Calcium acetate anhydrous is an authorised phosphate binder used in end-stage kidney disease.
- It works by binding dietary phosphate in the gut so the phosphate is passed in the stool.
- In trial NCT05680818, calcium acetate is part of the standard-of-care comparison arm, not the investigational drug.
- The trial is a Phase 3 study comparing encaleret with standard of care in 60 participants with ADH1.
- The study measures albumin-corrected blood calcium and 24-hour urinary calcium excretion.
- The trial status is Authorised, meaning it has been approved but results are not yet available.
What is calcium acetate anhydrous?
Calcium acetate anhydrous is a calcium salt of acetic acid with the molecular formula C4H6CaO4 and a molecular weight of 158.17. It is classified as a phosphate binder, a type of medicine that reduces the amount of phosphate absorbed from food. The substance is a principal compound used as a phosphate binder in patients with chronic renal failure. It is an authorised medicine, marketed as calcium acetate capsules.
How does calcium acetate anhydrous work?
People with advanced kidney disease often cannot remove enough phosphate from the body, leading to high blood phosphate levels. Calcium acetate works by binding to dietary phosphate in the gut. When taken with meals, it combines with phosphate from food to form insoluble calcium phosphate, which is then excreted in the feces. Calcium acetate is highly soluble at neutral pH, which makes the calcium readily available for binding to phosphate in the proximal small intestine. Orally administered calcium acetate is absorbed into the body at a rate of up to about 40% under fasting conditions and up to about 30% under non-fasting conditions.
Which conditions is it used or studied for?
- Hyperphosphatemia in end-stage renal failure — calcium acetate is used to control high blood phosphate levels in people whose kidneys can no longer remove phosphate effectively.
- Autosomal dominant hypocalcemia type 1 (ADH1) — in trial NCT05680818, calcium acetate is part of the standard-of-care treatment arm used as a comparison against encaleret.
How is calcium acetate anhydrous given?
Calcium acetate anhydrous is given by mouth as capsules. Each capsule contains 667 mg of calcium acetate anhydrous. In trial NCT05680818, the standard-of-care arm includes calcium acetate anhydrous at a reported dose of 6650 mg taken orally, alongside other standard treatments such as calcitriol, calcium carbonate, colecalciferol, and alfacalcidol.
What do the clinical trials show?
One registered clinical trial lists calcium acetate anhydrous. The trial, NCT05680818, is a Phase 3 interventional study comparing encaleret with standard of care in 60 participants with autosomal dominant hypocalcemia type 1 (ADH1). Calcium acetate is not the investigational medicine in this trial; it appears as part of the standard-of-care comparison arm. The primary efficacy endpoint is the responder status of each participant, assessed through albumin-corrected blood calcium and 24-hour urinary calcium excretion. The trial status is Authorised, meaning the study has been approved but no results are yet available.
What side effects are known?
The provided sources do not list specific side effects for calcium acetate anhydrous. The product information describes its use for phosphate control in end-stage renal failure but does not include a side-effect profile in the available text.