FDA Grants 510(k) Clearance to Hydrogel Spacer for Prostate Cancer Radiotherapy
核心洞察
The FDA granted 510(k) clearance to Boston Scientific's SpaceOAR Flex System (搜索), a hydrogel spacer intended to move the anterior rectal wall away from the prostate during radiotherapy.
The clearance cites the randomized HYDROSPACE trial, which is testing the investigational SpaceIT Hydrogel System (搜索) against a marketed Boston Scientific perirectal spacer.
HYDROSPACE plans to enroll about 230 patients with low- to intermediate-risk prostate cancer (搜索) at up to 35 sites in the US and Canada.
The FDA has cleared the SpaceOAR Flex System (搜索), a hydrogel spacer from Boston Scientific, through the 510(k) premarket notification pathway, according to the agency's premarket notification database. The agency determined the device is substantially equivalent to a legally marketed predicate. Boston Scientific submitted the traditional 510(k) on June 25, 2026, and the FDA issued its substantially equivalent decision on September 11, 2026. The device is classified as a hydrogel spacer under product code OVB and regulation number 892.5725, reviewed by the radiology panel. The submission was not reviewed by a third party, the device is not a combination product, and no predetermined change control plan was authorized with the clearance. Devices in this classification are intended to temporarily position the anterior rectal wall away from the prostate during radiotherapy to reduce radiation dose to the rectum.
The 510(k) record lists the randomized HYDROSPACE trial (NCT06451614) as the supporting clinical study. HYDROSPACE is a prospective, randomized, multicenter study evaluating the safety and effectiveness of the investigational SpaceIT Hydrogel System (搜索) in patients undergoing external beam radiotherapy (EBRT) for prostate cancer (搜索). Patients in the investigational arm receive the SpaceIT Hydrogel System, while the control arm receives a commercially marketed Boston Scientific perirectal hydrogel spacer, either the SpaceOAR System or SpaceOAR Vue Hydrogel (搜索). Eligible patients are 18 years or older with pathologically confirmed invasive adenocarcinoma of the prostate planning to undergo EBRT, with clinical stage T1 to T2c disease per AJCC eighth edition staging, a Gleason score of 7 or less on a biopsy taken within 12 months of baseline, and a prostate-specific antigen level of 20 ng/mL or less measured within 6 months of baseline and before starting androgen deprivation therapy. Concurrent ADT is permitted within protocol-defined timing windows. Key exclusion criteria include known sensitivity or allergy to polyethylene glycol and an inability to undergo a pelvic MRI.
According to a trial-in-progress abstract presented at the 2025 ASTRO Annual Meeting, approximately 230 patients are expected to be randomly assigned 1:1 to the pre-formed iodinated hydrogel or the commercially available polyethylene glycol-based hydrogel control, with enrollment at up to 35 sites in the US and Canada. The primary safety end point is the rate of acute grade 3 or higher adverse effects arising within 90 days of the index procedure, including all AEs listed on the labels of commercially available hydrogel perirectal spacers. The primary effectiveness end point is a clinically relevant dose reduction, defined as a 25% reduction in the volume of the rectum receiving 90% of the prescribed radiation dose. The sample size was calculated based on the primary safety end point. The first-generation SpaceOAR hydrogel received FDA authorization in April 2015 and is visible primarily on MRI, typically requiring a post-placement prostate MRI for radiotherapy planning. Its successor, SpaceOAR Vue, is an iodinated hydrogel visible on CT, which removes the need for a post-procedure MRI for treatment planning, and received 510(k) clearance in July 2019.