In short
Clinical trials investigating Alfacalcidol are studying how it is used in conditions linked to low calcium and parathyroid problems. These studies look at how well it works, how safe it is, and which patients may benefit, including people after bariatric surgery and people with hypoparathyroidism or ADH1.
Key points
- Clinical trials investigating Alfacalcidol are focused on calcium and parathyroid disorders, especially hypoparathyroidism and secondary hyperparathyroidism after bariatric surgery. All of the listed studies are Phase 3 trials, so they are testing treatment effects in larger patient groups. Some trials compare Alfacalcidol-related standard treatment with newer options, while others measure blood calcium, PTH, urine calcium, or quality of life. The patient groups include adults with chronic hypoparathyroidism, people with ADH1, and people after Roux-en-Y gastric bypass surgery. One study also looks at brain structure and blood flow in patients with chronic hypoparathyroidism. The trial data show that Alfacalcidol is being studied as part of real-world treatment strategies for these conditions.
Trial overview
These clinical trials study Alfacalcidol in patients with disorders that affect calcium balance and parathyroid hormone control.
The trial set includes studies in people with secondary hyperparathyroidism after bariatric surgery, hypoparathyroidism, and autosomal dominant hypocalcemia type 1 (ADH1).
All listed studies are Phase 3 trials, which means they are later-stage studies that test treatment effects in larger patient groups.
Conditions and patient groups
One study, called ActiVitD, focuses on secondary hyperparathyroidism after Roux-en-Y gastric bypass (RYGB), a type of bariatric surgery used for weight loss. The study is designed for patients who have high or high-normal PTH together with normal or low calcium levels and enough vitamin D in the blood.
Two records for NCT05778071 describe a study in patients with chronic hypoparathyroidism, including a main treatment period and a withdrawn record with the same study title. The trial looks at people who need treatment with active vitamin D and oral calcium.
NCT05680818 studies patients with ADH1 and compares encaleret with standard of care treatment, which includes ALFACALCIDOL and calcium-based treatments.
The 2025-523930-14-00 study includes patients with chronic hypoparathyroidism and compares conventional treatment, which includes Alfacalcidol and calcium supplements, with TransCon PTH treatment.
What the trials measure
The ActiVitD trial measures whether PTH becomes normal at 2 years after diagnosis and treatment start. This is the main sign that secondary hyperparathyroidism may have improved.
The CALYPSO trial for hypoparathyroidism measures whether patients can become independent from active vitamin D and reduce oral calcium needs after 24 weeks, while keeping albumin-adjusted serum calcium in the normal range.
The ADH1 study measures responder status, and its summary says it is designed to test changes in albumin-corrected blood calcium and 24-hour urinary calcium excretion.
The 2025 study measures differences in microvascular hemodynamic, which means blood flow in very small vessels, between patients treated with PTH and those treated with conventional therapy. It also aims to study quality of life, cognitive function, brain structure, and cerebral capillary blood flow.
Trial phases and designs
All of the listed studies are interventional trials, so patients receive a treatment or comparison treatment as part of the study plan.
The ActiVitD study is a multicenter randomized controlled trial, which means it is run at more than one center and patients are assigned to study groups by chance.
The CALYPSO study includes a placebo comparison, meaning some patients receive a look-alike treatment without active study drug so the results can be compared fairly.
The ADH1 study compares encaleret with standard of care treatment, and the 2025 study compares TransCon PTH with conventional treatment.
How Alfacalcidol is used in the studies
In these trial records, Alfacalcidol appears as part of standard or conventional treatment for calcium and parathyroid disorders.
In the ADH1 study, ALFACALCIDOL is listed alongside calcium carbonate, calcium acetate, and calcitriol in the standard treatment arms.
In the chronic hypoparathyroidism study, Alfacalcidol is listed as part of conventional treatment with calcium supplements when compared against TransCon PTH.
The ActiVitD study summary says it is investigating the effect of alfacalcidol on secondary hyperparathyroidism after RYGB surgery.
Important patient points
These studies are aimed at people with specific diagnoses, not general use in all patients with low calcium or bone problems.
Patients are usually selected based on their diagnosis, blood test results, and current treatment needs.
The main results measured in these trials are blood calcium, PTH, urine calcium, and patient-centered outcomes such as quality of life and brain-related measures.
Because these are Phase 3 studies, they are important for understanding whether treatment strategies that include Alfacalcidol work well in real patient groups.