Using Denosumab to treat Fibrous Dysplasia and McCune-Albright Syndrome in adults

DEnosumab for the Treatment of FIbrous Dysplasia/McCune-Albright Syndrome in Adults (DeFiD): a Randomized Double-blind Placebo-controlled Trial

Phase 4 Interventional Leiden University Medical Center · NCT05966064

This study is testing if Denosumab can help adults with Fibrous Dysplasia and McCune-Albright Syndrome feel less pain and improve their condition compared to a placebo.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment82 (estimated)
Ages18 Years and up
SexAll
SponsorLeiden University Medical Center Academic / other
Drugs / interventionsDenosumab
Locations1 site (Leiden)
Trial IDNCT05966064 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates the efficacy of Denosumab, a RANKL-inhibitor, in improving the clinical, radiological, and biochemical manifestations of Fibrous Dysplasia and McCune-Albright Syndrome in adults. Patients will be randomized to receive either Denosumab or a placebo, with treatment administered every three months. The study aims to assess pain levels and lesional growth, allowing patients with inadequate pain relief to continue with Denosumab in an open-label phase after six months. The trial seeks to provide a potential new treatment option for a condition that currently lacks effective therapies.

Who should consider this trial

Good fit: Ideal candidates are adults over 18 with symptomatic Fibrous Dysplasia or McCune-Albright Syndrome who experience significant pain not relieved by standard treatments.

Not a fit: Patients with pain unrelated to Fibrous Dysplasia or those with uncontrolled endocrine diseases may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly reduce pain and improve quality of life for patients suffering from Fibrous Dysplasia and McCune-Albright Syndrome.

How similar studies have performed: Previous studies have shown promising results with Denosumab in similar conditions, suggesting potential for success in this trial.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Symptomatic patients with established diagnosis of FD/MAS and closed growth plates(\>18 years)
* Pain in the region of an FD localization, not responding to adequate pain treatment and without mechanical component e.g. impending fracture
* Pain score from FD lesion for maximum or average pain on VAS ≥ 4
* Increased lesional activity defined as increased bone turnover markers (ALP, P1NP or CTX) or increased activity on Na\[18F\]-PET/CT or bone scintigraphy in at least one lesion
* Normal levels of calcium, parathyroid hormone and vitamin D (supplementation is allowed)
* Treated hypophosphatemia (defined as \>0.7 at two separate measures)
* good dental health (last check within the last 12 months)

Exclusion Criteria:

* Active pregnancy wish, pregnancy or nursing
* Pain not related to FD
* Uncontrolled endocrine disease
* Untreated vitamin D deficiency, hypocalcemia or hypophosphatemia
* Previous use of bisphosphonates or Dmab \< 6 months before inclusion ('6 months wash out')
* Previously reported severe side effects on Dmab
* Inability to fulfil study requirements
* Poor untreated dental health without intention to get treatment
* Treatment with other bone influencing drugs, such as high doses corticosteroids

Where this trial is running

Leiden

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Fibrous DysplasiaMcCune Albright Syndrome
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.