Important unanswered questions
Studies suggest men with vasculogenic ED are among the most ideal candidates for shock wave therapy, but it’s not clear if they are the only ones. Ideal protocols for delivering the therapy also remain unclear, Dr. Hatzichristodoulou said.
“The ideal protocol is not only how many sessions the patient needs to have but also how many shock waves? And what energy level should we use to treat the patient with erectile dysfunction?” he said. “The third question is, there are a lot of devices on the market, but we do not know which is the best one for which patients.”
Limited data in the U.S.
FDA approval for a low-density extracorporeal shock wave device to treat ED likely is years away, according to Ranjith Ramasamy, MD, assistant professor of urology and director of male reproductive medicine and surgery at the University of Miami.
According to the AUA erectile dysfunction guidelines published in 2018, low-intensity extracorporeal shock wave therapy should be considered investigational for men with ED.
“The guidelines basically say that because this is not FDA approved, it should be used only under an IRB-approved protocol,” Dr. Ramasamy said. “Unfortunately, there are a lot of studies that demonstrate that it is efficacious and safe, but the majority of these studies that have been published are from outside the U.S. At the University of Miami, we have an ongoing clinical trial. Patients who wish to seek shock wave therapy for ED should be encouraged to look for clinical trial opportunities and enroll in them.”
In March 2019, the Sexual Medicine Society of North America issued a position statement on restorative therapies for ED, including low-intensity shock wave therapy, stating that the use of such therapies is experimental and should be conducted under research protocols (see, “SMSNA: Shock waves for ED not ready for mainstream").
Dr. Ramasamy and colleagues recently finished a phase II trial looking at the MoreNova shock wave therapy device, made by Direx.
The trial compared two different dose regimens. In group A, a total of 3,600 shocks were given over a period of 5 days. In group B, the regimen was a total of six treatments given 3 days a week (Monday, Wednesday, and Friday) for 2 weeks in a row.
The trial revealed shock wave therapy worked well to restore erectile function in men with mild to moderate vasculogenic ED. It did not have an effect in men with severe erectile dysfunction resulting from diabetes or in those who had undergone prostatectomy, cystectomy, or radiation. Nor did it have an effect in men with Peyronie’s disease. There was no sham arm in the trial to evaluate for placebo effect.
Researchers don’t yet know how long shock wave treatment benefits last in men with ED, according to Dr. Ramasamy, who is an investigator for Direx.
“In the trial that we have completed, 60% of men appear to respond to shock wave therapy by achieving the minimal clinically important difference in International Index of Erectile Function scores at the end of 6 months without taking any kind of PDE-5 inhibitors. We have recently commenced a phase III trial with a sham arm and follow-up for 12 months,” Dr. Ramasamy said.
“Some of the trials have demonstrated a benefit up to 12 months, but that’s probably the longest time that we know that shock wave therapy can provide a benefit for.”
On the upside, shock wave therapy is unlike other ED treatment options in that it offers a potential cure for ED.
“I think that in patients with mild to moderate erectile dysfunction, it can reverse the pathophysiology of the disease and not merely treat the condition and potentially restore erectile function,” Dr. Ramasamy said.
Drawbacks of the therapy are that urologists and others would offer it as an in-office treatment that would require patients to make several office visits.
“Each of the treatments are about 30 minutes long,” Dr. Ramasamy said. “The biggest drawback is, you don’t know who is going to respond and who isn’t.”
Another potential drawback is cost. When providers use it off-label, outside the research setting, shock wave therapy protocols can cost from $3,000 to $6,000, according to Dr. Ramasamy.