FDA grants Breakthrough Device designation to microRNA blood test for predicting AIS curve progression

For clinicians who identify adolescent idiopathic scoliosis (AIS) during routine screening, the hardest question is often not whether a curve exists but whether it will worsen. The FDA has granted Breakthrough Device designation to ScolimiR-3D, an in vitro diagnostic that measures 6 circulating microRNAs from a standard blood draw to classify a patient's risk of developing a severe spinal curve, VB Spine LLC announced September 29, 2026.¹ The company said it is the first such designation granted to a predictive scoliosis risk assessment test.¹

Alain Moreau, whose laboratory at the Azrieli Research Centre of CHU Sainte-Justine and Université de Montréal developed the underlying science, said the core clinical challenge is "not simply detecting the curve—it is knowing where that curve is going."¹

ScolimiR-3D microRNA panel and validation data in AIS

The test is based on a prospective cross-sectional study published in Scientific Reports in February 2025.² Investigators collected plasma at diagnosis from 116 skeletally immature, untreated patients with AIS (mean age, 13.3 years; mean Cobb angle, 24.4°) at 3 pediatric spine centers and followed them to skeletal maturity or surgery.²

Patients were stratified as severe progressors (final Cobb angle ≥45°), moderate progressors (25°-44°), or nonprogressors.² Genome-wide profiling identified 15 microRNAs upregulated in patients who developed severe curves.²

A random forest model using 6 of those microRNAs (miR-1-3p, miR-19a-3p, miR-19b-3p, miR-133b, miR-143-3p, and miR-148b-3p) distinguished severe progressors from nonprogressors with 100% accuracy, sensitivity, and specificity (AUC, 1.0).² Those metrics came from a randomly selected 20% of cases held out as a test set after the model was trained on the remaining 80%.²

AIS prevalence, bracing outcomes, and the need to predict curve progression

AIS affects an estimated 2% to 4% of adolescents and is the most common orthopedic condition requiring surgery in this age group.² No validated test currently identifies at diagnosis which patients will progress, so bracing or surgery is often deferred until progression is documented on serial radiographs.²

Bracing is effective for high-risk curves. In the Bracing in Adolescent Idiopathic Scoliosis Trial (BrAIST), which enrolled patients aged 10 to 15 years with curves of 20° to 40°, treatment success (skeletal maturity without progression to ≥50°) was 72% with bracing vs 48% with observation.⁴ That nearly half of observed patients did not progress also highlights how difficult it is to identify who truly needs treatment.⁴

VB Spine said the test could help clinicians match conservative treatment such as bracing to a patient's risk and support family counseling from diagnosis onward.¹

What FDA Breakthrough Device designation means for the scoliosis blood test

The Breakthrough Devices Program is a voluntary pathway for devices that may provide more effective diagnosis or treatment of life-threatening or irreversibly debilitating conditions.³ Designated sponsors receive more interactive communication with the agency and priority review, but devices must still meet the standard for premarket approval, 510(k) clearance, or De Novo authorization.³

Limitations of the ScolimiR-3D microRNA evidence and next steps

Perfect accuracy in a small holdout set warrants caution. The discovery cohort included 69 patients with AIS and the replication cohort 35, so the 20% test set represented a small number of patients, and the 6-microRNA panel was evaluated for separating severe progressors from nonprogressors rather than across the full range of outcomes.² Adding all 15 microRNAs lowered accuracy to 90% and specificity to 88%.²

The authors acknowledged that participants were a homogeneous population of European ancestry and that findings require replication in larger, more diverse pediatric cohorts.² Samples were collected between 2002 and 2013.² The work was partly funded by Medtronic Canada, and CHU Sainte-Justine holds a pending patent application.²

Independent, prospective external validation will be essential before clinicians can rely on the test to guide bracing decisions. VB Spine said additional supporting research is expected at the Scoliosis Research Society 2026 Annual Meeting, October 6 to 10 in Sydney, Australia.¹

References

1. VB Spine announces FDA Breakthrough Device designation for new blood test designed to identify patients at risk for scoliosis progression. News release. VB Spine LLC. September 29, 2026. Accessed September 29, 2026. https://www.businesswire.com/news/home/20260929164733/en/

2. Khatami N, Caraus I, Rahaman M, et al. Genome-wide profiling of circulating microRNAs in adolescent idiopathic scoliosis and their relation to spinal deformity severity, and disease pathophysiology. Sci Rep. 2025;15(1):5305. doi:10.1038/s41598-025-88985-3

3. US Food and Drug Administration. Breakthrough Devices Program: guidance for industry and Food and Drug Administration staff. September 2023. Accessed September 29, 2026. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/breakthrough-devices-program

4. Weinstein SL, Dolan LA, Wright JG, Dobbs MB. Effects of bracing in adolescents with idiopathic scoliosis. N Engl J Med. 2013;369(16):1512-1521. doi:10.1056/NEJMoa1307337