FDA Grants 510K Clearance to Exablate System for Prostate Cancer

The FDA has awarded 510K clearance to the Exablate Prostate system for the treatment of prostate cancer, according to an announcement from the device manufacturer, Insightec.¹ Exablate utilizes high intensity focused ultrasound to ablate targeted tissue in the prostate.

“Exablate Focused Ultrasound has been shown to provide effective control of locally-confined prostate cancer in select patients based on 2-year biopsy outcomes,” principal investigator Behfar Ehdaie, MD, MS, a urologic surgeon at Memorial Sloan Kettering Cancer Center, stated in a news release. “Precision ablation together with MR imaging and thermal feedback may enable men to consider a tissue-preserving approach and defer or avoid radical therapy.”

Final results from a phase 2b study (NCT01657942) presented during the 2021 AUA Annual Meeting suggested that magnetic resonance (MR)–guided focused ultrasound (MRgFUS) focal therapy may represent an effective alternative to radical therapy, one that improves quality-of-life (QoL) measures such as sexual function and urinary incontinence.

At 24 months, 88% of men had no evidence of grade group 2 or 3 prostate cancer in the treatment area according to targeted prostate biopsy. Additionally, 60% of men had no evidence of grade group 2 or 3 disease anywhere in the prostate gland, including outside of the treatment area. Serum PSA levels decreased by almost 50% after treatment and stabilized after 6 months.²

Investigators evaluated MRgFUS in a single-arm, multicenter trial of 101 men who were treated at 7 academic centers and 1 private practice from May 2017 to December 2018. MRgFUS was delivered focally to the lesion with a margin of normal tissue of greater than, or equal to, 5 mm based on planning. Treatment was monitored with real-time MR thermometry. Concurrent grade group 1 prostate cancer foci were not treated.

To be eligible for enrollment, patients needed to have been diagnosed with untreated, unilateral, and more visible grade group 2 or 3 prostate cancer. Those who could not to undergo MRI or who had large calcification between the rectum and the planned targeted treatment zone that could potentially interfere with treatment were excluded.

Investigators conducted targeted and systematic biopsies at 6 and 24 months after treatment, and examinations with QoL measurements were done every 3 months. The primary end points of the trial were efficacy and safety. A key secondary end point was change in baseline patient-reported QoL at 24 months.

The average patient age was 63 years and 86% of the cohort was White. The median prostate-specific antigen was 5.7 ng/mL. Moreover, 83% of patients had at least clinical stage T1c disease; 78% of patients were in grade group 2 and 22% were in grade group 3.

“This device is unique in that because it's done during real-time MRI imaging while the patient is in the MRI machine, we can monitor the temperatures achieved by our treatment in real time and make adjustments in real time,” Ehdaie said in an October interview with Urology Times.³ “What that means is that we're able to determine areas that will be sensitive to the treatment, both cancer and areas from a quality-of-life perspective.

Lower urinary tract symptoms were similar at baseline and 24 months (mean score difference, 1.1; 95% CI, 0.33-1.8). Erectile function scores were slightly worse at 24 months compared with baseline (HR, -3.5; 95% CI, -5.4 to -1.6). Thirteen percent of patients reported no sexual activity and 81% of patients achieved erections adequate for intercourse.

“Over 75% of patients in the study returned back to functional erections without the need for additional erectile dysfunction medications,” Ehdaie added. “That's a high bar we used to define sexual function, but those numbers were very encouraging. Of those, we had over 65% of patients by 2 years achieve functional erections with the additional medications, so what we can tell patients is that having this treatment, from a quality-of-life perspective, can achieve superior outcomes compared to whole-gland treatments.”

No serious adverse effects (AEs) were reported, and most minor or moderate AEs self resolved by 90 days. Two patients had ejaculation disorder and 1 experienced hematospermia beyond 90 days.

References

1. Insightec announces FDA clearance for Exablate Prostate to treat prostate tissue. News release. Insightec; December 1, 2021. Accessed December 6, 2021. https://prn.to/3m1gdGf
2. Ehdaie B, Tempany C, Holland F, et al. MRI-guided focused ultrasound (MRgFUS) focal therapy for intermediate-risk prostate cancer: final results of a phase IIb multicenter study. Presented at: 2021 American Urological Association Annual Meeting; September 10-13, 2021; virtual. Abstract LBA02-12.
3. Hart J. Phase 2b data point to safety, efficacy of focal therapy in intermediate-risk prostate cancer. Urology Times; October 1, 2021. Accessed December 6, 2021. https://bit.ly/3rGXx1T