The findings were recently reported at the 59th Annual Meeting of the American Society for Radiation Oncology in San Diego, in a presentation titled, “Multi-Institutional Phase 2 Trial of High-Dose Stereotactic Body Radiation Therapy with Temporary Hydrogel Spacer for Low- and Intermediate-Risk Prostate Cancer.”
“We are excited by the successful results from this study, as it is the first time we’ve evaluated SpaceOAR Hydrogel in prostate cancer patients treated with high-dose SBRT, and the findings confirm a significant clinical benefit,” John Pedersen, CEO of Augmenix, said in a press release. “As this robust data indicates we remain steadfast in our vision to develop disruptive medical technology that improves the lives of patients receiving radiation therapy.”
While higher radiation doses are better at killing tumors, the amount of radiation delivered is often limited by the proximity of healthy tissues. In prostate cancer patients, the rectum’s proximity is often a problem, as prostate cancer radiation can cause long-term damage to the rectum and other side effects.
To overcome this, Augmenix developed a spacer that safely separates the prostate from the rectum. SpaceOAR Hydrogel is an injectable liquid that solidifies into a soft hydrogel, creating a physical barrier between the two organs. The gel is stable for three months, after which it returns to its initial liquid state and is absorbed by the body.
Studies have shown that the spacer is effective in protecting prostate-surrounding tissues after Intensity Modulated Radiation Therapy (IMRT), with significant long-term benefits for bowel, urinary, and sexual function.
IMRT is a high-precision radiotherapy that delivers radiation doses into a tumor, or specific areas within a tumor, while minimizing the dose to surrounding normal structures. But studies suggest that SBRT might be less expensive and faster for prostate cancer patients.
The multi-institutional Phase 2 study (NCT02353832) evaluated the safety and effectiveness of the SpaceOAR System in patients undergoing SBRT for the treatment of low- to intermediate-risk prostate cancer.
The study included 44 men treated at the University of Texas Southwestern Medical Center and Memorial Sloan Kettering Cancer Center with high-dose (45 Gray) SBRT given in five sessions.
Only six patients, or 13.6%, experienced rectal mucosal injury due to high rectal wall radiation doses. All were mild symptoms and healed completely within six months after treatment.
This contrasted significantly with the 90% of patients experiencing rectum toxicity in other SBRT studies.
Also, none of the participants showed signs of cancer recurrence within a 12-month follow-up period.
“High-dose regimens have provided exceptionally high rates of biochemical control, but at the cost of an increased risk of rectal complications associated with the rectal wall dose,” said Michael Folkert, MD, radiation oncologist and brachytherapy specialist at University of Texas Southwestern Medical Center in Dallas. “Our new study demonstrates that use of the perirectal hydrogel spacer gets us the ‘room’ we need to safely deliver the most potent therapeutic doses to patients, which may ultimately lead to the optimal cancer control while significantly reducing the risk of treatment related complications.”
SpaceOAR Hydrogel was the first and only prostate cancer spacing device to be approved so far by the U.S. Food and Drug Administration (FDA).