In the pivotal study, almost all of the patients (97%) treated with HIFU had an adverse event; 82% had a moderate or severe adverse event. Adverse events included erectile dysfunction in 67%, urinary retention in 49%, urinary incontinence in 39%, urinary stricture in 35%, urethral injury in 15%, and bowel dysfunction in 21%. Most of these adverse events resolved in most patients over time, but at 24 months, 44% of the treated patients still had erectile dysfunction.
The FDA reviewers said that it was unclear whether HIFU therapy provides a benefit for patients with low-risk prostate cancer, and said that they were concerned about the 28% positive biopsy rate in the pivotal trial. Based on the evidence provided, "we can conclude that a single whole-gland HIFU treatment session does not get rid of all the cancer within the prostate gland in a significant percentage of patients," said one of the FDA reviewers, Dr. Jonathan Jarow of the FDA’s office of hematology and oncology products in the FDA’s Center for Drug Evaluation and Research. The FDA has never approved a treatment for prostate cancer based on PSA results, he pointed out.
Panelists generally agreed that the biochemical survival rate at 2 years using the Phoenix criteria could not be used to show the treatment was effective for a nonradiation treatment in patients with low-risk prostate cancer, pointing out that the criteria had not been validated with this technology. Several panelists said that the device might be effective but that it was not possible to determine that with the available data.
In a statement issued by EDAP after the meeting concluded, Marc Oczachowski, the company’s chief executive officer, said that the company "will continue to work diligently with the FDA as it carefully completes its final review" of the Ablatherm HIFU application.
The device has been used to treat about 40,000 patients with low-risk disease worldwide, according to EDAP.
The FDA usually follows the recommendations of its advisory panels. Panel members have been cleared of potential conflicts.