Staff WriterIf you’ve ever wondered why new osteoporosis medications can take so long to reach people who need them, the answer is simple and frustrating: the outcome that matters most, fractures, can take years and very large studies to measure.
That’s why a recent FDA decision is getting attention in bone-health circles.
On December 19, 2025, the FDA qualified the percent change in total hip bone mineral density (BMD) at 24 months, measured by DXA, as a validated surrogate endpoint for Phase 3 clinical trials of investigational therapies in postmenopausal women with osteoporosis at risk for fracture.
In everyday terms: drug trials may be able to use a trusted bone-density change at the hip as a stand-in for fracture outcomes, which could make trials more efficient and potentially bring new options to patients sooner.
But there’s a catch worth understanding: surrogate endpoints can speed access, but they don’t automatically prove the thing patients care about most, fewer fractures and better function in real life. The FDA’s framework is designed to balance both realities.
Why osteoporosis trials have been slow (and why patients feel that delay)
Osteoporosis is often called a “silent disease” until it isn’t, because the first clear sign can be a fracture that changes everything: mobility, independence, confidence, and, for some, survival.
In the U.S., about one in two women and up to one in four men over age 50 will break a bone due to osteoporosis, according to the Bone Health & Osteoporosis Foundation (BHOF).
The FDA similarly emphasizes the public-health burden of osteoporosis fractures and the need for new therapies with improved safety and efficacy.
Historically, Phase 3 osteoporosis trials often had to wait for enough fractures to occur to show a statistically meaningful difference. The FDA notes these fracture-endpoint trials can require large studies lasting two to five years.
That timeline matters to real people:
a woman told she has “osteopenia” until the day she suddenly doesn’t
a 62-year-old who already had a wrist fracture and is afraid of the next fall
a 71-year-old caregiver who can’t afford months of reduced mobility
What the FDA actually did: “qualified” total hip BMD change for a specific use
This decision is not “FDA approved a new drug.” It’s about how future drugs can be tested.
The FDA qualified percent change from baseline at 24 months in total hip BMD (DXA-measured) as a validated surrogate endpoint for Phase 3 trials in postmenopausal women with osteoporosis at risk for fracture.
What “qualified” means in FDA language
“Qualification” is a regulatory term with a specific meaning: within a defined context of use, the biomarker has been demonstrated to reliably support a specific interpretation and application in drug development, and can then be used across multiple programs without FDA needing to re-litigate its suitability each time.
Also important: FDA qualifies the biomarker, not the specific test device used to measure it in clinical care (even though a reliable measurement method is required).
Why total hip BMD, and why now?
Hip fractures are among the most consequential osteoporosis outcomes. BMD has always been clinically meaningful, but the question for regulators has been: does changing BMD reliably predict fewer fractures across therapies and trial designs?
A major effort called the SABRE project (a multi-sector partnership involving FNIH and ASBMR) assembled large individual-patient datasets from many randomized trials to examine how treatment-related changes in total hip BMD relate to fracture risk reduction.
That work is part of the scientific foundation that enabled FDA to treat total hip BMD change as a validated surrogate endpoint in this setting.
The patient-friendly truth about surrogate endpoints: what they do and don’t prove
What a surrogate endpoint is
A surrogate endpoint is a measure used in a clinical trial instead of a direct measure of how a patient feels, functions, or survives. It’s expected to predict clinical benefit, but it’s not the benefit itself.
“Validated” vs “reasonably likely”
FDA describes levels of confidence in surrogate endpoints:
- Validated surrogate endpoints have strong evidence that an effect on the surrogate predicts a specific clinical benefit and can support traditional approval.
- Reasonably likely surrogate endpoints can support accelerated approval, but require confirmatory trials to verify clinical benefit.
In this osteoporosis decision, FDA used the phrase validated surrogate endpoint for the qualified total hip BMD measure in the stated context of use.
What surrogate endpoints can miss
Even with validated surrogates, there are real limitations patients should understand:
- They may not capture off-target harms. FDA notes that improving a surrogate in one setting can still turn out to be ineffective or harmful in another if the therapy has additional effects not measured by the surrogate.
- They don’t automatically measure function. A higher BMD doesn’t directly measure fall risk, balance, muscle strength, vision, or home hazards.
- They don’t tell the whole “fracture story.” Hip BMD is powerful, but fractures also happen in the spine, wrist, and elsewhere, and patient populations vary.
So the balanced takeaway is:
- This change can make trials faster and smaller.
- But good drug development still requires careful safety data, real-world follow-up, and a clear understanding of who benefits.
Why this could speed development (and what “faster” might look like)
The FDA explicitly notes that relying on fracture endpoints often means trials that are large and 2–5 years long, and that qualifying BMD as a surrogate endpoint could make trials more efficient and improve access.
Potential effects:
- Shorter, more feasible Phase 3 trials for new mechanisms
- More companies willing to invest in osteoporosis R&D because the path is clearer
- Earlier “go/no-go” decisions on candidates that improve hip BMD meaningfully
- More innovation in safety (a major concern for long-term therapy decisions)
This doesn’t mean every future osteoporosis drug will be approved overnight. But it can reduce one of the biggest bottlenecks: waiting years for enough fracture events.
What this means for patients right now (even before any new drug arrives)
This decision is about future trials, but it reinforces a practical point for patients today:
1) DXA is not “just a number”
DXA is how total hip BMD is measured, and it’s now central not just to diagnosis and monitoring, but also to the way new therapies may be evaluated.
2) Screening still matters, because most people are diagnosed late
USPSTF recommends:
- Screen women 65+ with DXA (with or without fracture risk assessment)
- For postmenopausal women under 65, screen based on risk factors and risk tools
- Evidence is insufficient to recommend routine screening in men
3) Fracture prevention is bigger than medication
Even with better drugs, fractures are influenced by:
- fall risk and home safety
- strength and balance
- vision and medications that affect dizziness
- nutrition and vitamin D status
- whether people actually get evaluated after a “minor” fracture
BHOF and other organizations have long pointed out that many people do not connect fragility fractures to osteoporosis risk, leading to missed treatment opportunities.
What to ask your clinician if you’re over 50 and worried about bone health
These questions keep the visit grounded in what matters:
- “Based on my age and risk factors, do I need a DXA scan now?”
- “What is my fracture risk, not just my T-score?” (many clinicians incorporate fracture risk tools alongside BMD)
- “If medication is recommended, what’s the plan for duration, follow-up, and reassessment?”
- “What are my top fall-risk factors, and what’s one change I can make this month?”
FDA’s decision to qualify total hip BMD change as a surrogate endpoint is the kind of policy shift most patients never hear about, yet it can shape what options exist five years from now.
The hopeful part: faster, clearer trials can translate into faster access to new therapies, especially for people at high fracture risk.
The honest part: surrogate endpoints are tools, not guarantees. They can strengthen decision-making, but they don’t replace careful safety evaluation or the lived reality that fracture prevention is also about falls, strength, and follow-through.
That’s the real patient-centered framing:
Speed matters. Evidence matters. And outcomes in real bodies matter most.
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