Device-related problems and event rates for PEG hydrogel spacers appear low

Overall device-related problems and event rates for polyethylene glycol (PEG) hydrogel spacers (SpaceOAR) consistently remained below 1% relative to the estimated device usage in patients with prostate cancer, according to data from a real-world analysis presented during a poster session at the 2024 American Society for Radiation Oncology Annual Meeting in Washington, DC.¹

Michael R. Folkert, MD, PhD

PEG hydrogel spacers are used to reduce toxicity to the rectum in patients undergoing radiotherapy for prostate cancer.

The results were presented by Michael R. Folkert, MD, PhD, who is the chief of brachytherapy and a professor of radiation oncology at the Fred Hutchinson Cancer Center at the University of Washington School of Medicine in Seattle.

According to the authors, “Previously published analyses of PEG hydrogel spacers using the [FDA’s] Manufacturer and User Facility Device Experience (MAUDE) passive surveillance database have not taken into account the real-world volume of spacers placed as part of standard of care following approval. To contextualize the MAUDE reports for the spacers, we assessed the device-related issues and patient event rates from the database, factoring in a conservative estimate of total spacer units used in the US.”

For the analysis, the investigators assessed a total of 1005 safety reports for PEG hydrogel spacers in the context of an estimated 251,836 units sold from January 2015 to September 2023. This translates to an overall report rate per unit sold of 0.40% (range, 0.00% in 2015 to 0.57% in 2023) during the study period. The highest incidence of medical device reports was in 2022, with a yearly report rate of 0.68% (n = 340).

Among all reports, 743 (0.30% of total units sold) reported device issues were due to an issue with placement/positioning of the device, and 212 (0.08% of total units sold) reported device issues were due to an “adverse event without identified device or use problem.”

Of those related to an issue with placement/positioning of the device, approximately 60% of patient events reported had “no clinical signs, symptoms, or conditions” and “no consequences or impact to patient” (456 reports, 0.18% of total units sold). A total of 158 reports related to placement/positioning of the device were due to pain/discomfort (0.06% of total units sold).

Overall, the most frequently reported patient events included 440 for “no clinical signs, symptoms, or conditions” (0.17% of total units sold) and 278 for “pain/discomfort” (0.11% of total units sold). Other commonly reported events included infection (132 reports, 0.05% of total units sold), fistula (92 reports; 0.03% of total units sold), hemorrhage/blood loss/bleeding (83 reports; 0.03% of total units sold), and urinary dysfunction (77 reports; 0.03% of total units sold).

Based on these data, the authors note that a majority of reported device-related problems and events for PEG hydrogel spacers appear to have little or no reported clinical consequence.

They concluded, “Although still a valuable source of information, given the known limitations of MAUDE, additional real-world evidence may help support making informed decisions involving the incorporation of this technology into prostate cancer treatment to potentially mitigate rectal toxicity in men undergoing radiotherapy for prostate cancer.”

Reference

1. Folkert MR, Shin Y, Vannan D, Rojanasarot S. Real-world medical device reports of PEG hydrogel spacers: Analysis of the FDA Manufacturer and User Facility Device Experience (MAUDE) Database. Presented at: American Society for Radiation Oncology Annual Meeting. September 29-October 2, 2024. Washington, DC. Poster 3169. https://www.redjournal.org/article/S0360-3016(24)01935-7/fulltext