Dive Brief:

• FDA has approved ApiFix's treatment for progressive adolescent idiopathic scoliosis (AIS) via its humanitarian device exemption (HDE) pathway.

• The device, called the Minimally Invasive Deformity Correction (MID-C) system, is designed to counter the abnormal curvature of the spine that characterizes AIS without requiring the patient to undergo spinal fusion.

• FDA, which approved the device Aug. 23, based its approval on data generated in people outside of the U.S., where the product has been used in more than 250 patients.

Dive Insight:

Patients with AIS, defined as lateral spine curvature of 10 degrees or more, have several treatment options. In some cases, the physician will recommend ongoing observation, with or without physical therapy. In other cases, patients will receive an external brace or undergo a procedure, such as spinal fusion, to correct the spinal curvature.

ApiFix wants to establish the MID-C system as a less-invasive alternative for AIS patients. The device is attached to the patient's spine. Once in place, a titanium alloy ratcheting rod expands in increments, gradually correcting the curvature of the spine.

The HDE pathway permits approval of devices to treat rare conditions primarily on safety grounds, freeing companies from the need to generate extensive efficacy evidence. ApiFix, which has sold the product in Europe since 2013, went to FDA with data on 252 patients but the agency zeroed in on a smaller subpopulation that met the U.S. indications for use and received the latest version of MID-C.

Among the eight patients with 24 months of follow up in FDA's target population, six met the criteria for probable benefit. On average, the curvature of the spine improved by 43%. ApiFix saw similar results in a larger, 20-patient cohort of people who met FDA's expanded target population criteria.

FDA said the "clinical data suggests that the MID-C System provides probable benefit related to prevention of the spinal curve progression and avoidance of spinal fusion."

The agency also viewed the safety data favorably. In the target population safety cohort, 12% of people required reoperation. FDA said the rate of reoperations "was somewhat higher than for spinal fusion" but nonetheless concluded the safety data supported approval of the device. 

Patients in the target population were 13 to almost 19 years old at the time of treatment. The focus on adolescents is in line with pediatric device approval trends at FDA. Most pediatric devices approved by FDA over the past decade have targeted people aged 12 to 21 years old.