FDA Approves Sonalleve MR-HIFU System for Osteoid Osteoma in the Extremities

The FDA has approved the Sonalleve MR-guided high-intensity focused ultrasound (MR-HIFU) system for the treatment of patients with osteoid osteoma in the extremities.¹

The treatment, which is manufactured by Profound Medical Inc., is an image-guided technique that combines high-intensity focused ultrasound ablation with real-time monitoring of temperature change during sonication.

The approval was based on data of 9 pediatric patients with osteoid osteoma who were treated with MR-HIFU, in whom the device showed efficacy without technical difficulties or led to serious adverse events (AEs). Results showed that there was a statistically significant decrease in pain scores within 4 weeks of treatment, and no pain medication was used in 8 of the 9 patients after 4 weeks.

Osteoid osteoma is a benign bone tumor that commonly presents in children and young adults.² Standard treatment options include surgical excision or CT-guided radiofrequency ablation. While the latter is more invasive, it requires the use of drilling from the skin through the muscle and soft tissue into bone, exposing the patient and operator to ionizing radiation.

Without the use of scalpels or needles, MR-HIFU is designed to provide precise and controlled delivery of focused ultrasound energy into a lesion with the use of an external applicator. MR-HIFU can also be administered quickly, with a procedure time of less than 2 hours. Previously, the approach has been used in clinical trials of adult patients with painful bone metastases.

In the small open-label, single-group assignment study (NCT02349971), patients with osteoid osteoma underwent a single procedure of MR-HIFU ablation while under sedation or anesthesia. The patients were monitored for their disease status, as well as AEs, for at least 1 year following their procedure.

To be eligible for enrollment, patients had to have a diagnosis of osteoid osteoma; had target lesions that could be located in any peripheral bone with acoustic accessibility, may be intracortical or juxtacortical in location, and must be reachable within the normal safety margins of HIFU; and had prior unsuccessful surgical resection or radiofrequency ablation. Additionally, patients needed to have hemoglobin greater than 9 g/dL, platelet count of at least 75,000/µL, age-adjusted normal serum creatinine or a creatinine clearance of at least 60 mL/min/1.73 m2 for safe contrast administration, and adequate pulmonary function.

Those with clinically significant unrelated systemic illness, implant or prosthesis or scar tissue that is within the HIFU path beam, lesion in the skull or vertebral body, inability to undergo MRI and/or have a contraindication for MRI, cannot tolerate stationary position during HIFU, or were receiving any investigational agents were excluded from enrolling on the study. Patients also could not have a target less than 1 cm from the nerve plexus, spinal canal, bladder, or bowl, nor of the growth plate.

The primary end point was safety and feasibility, measured by the number of patients who could be treated with MR-HIFU and did not report treatment-related AEs. Response was a secondary end point.

References

1. FDA approves device for treatment of osteoid osteoma in the extremities. News release. FDA. November 27, 2020. Accessed November 30, 2020. https://bit.ly/3occqEi
2. Safety and feasibility of MR-Guided High Intensity Focused Ultrasound (MR-HIFU) ablation of osteoid osteoma in children. ClinicalTrials.gov. January 29, 2015. Accessed November 30, 2020. https://bit.ly/37iV9Tb