Mixed Results on Two Treatments for Erectile Dysfunction

Sarah Tilyou

May 02, 2023

UPDATED May 5, 2023 // This article has been updated to include comments from Charles Runels, MD, and to disambiguate PRP injections from related, proprietary therapies.

Shock-wave therapy looks like an effective method for treating erectile dysfunction (ED), but injections of platelet-rich plasma (PRP) proved no better than placebo, according to results from two studies presented at the American Urological Association (AUA) 2023 Annual Meeting.

In a single-blind prospective study that evaluated low-intensity shock-wave therapy, researchers randomly assigned 36 men with ED to receive mechanical therapy (n = 22) or sham treatment (n = 14) on their flaccid penis.

The patients in arm 1 of the study received three treatments of 5000 shocks (4 Hz, 0.12 mJ/mm2) with the UroGold 1000 device (SoftWave) at weeks 0, 3, and 6. Those in arm 2 received a regimen of 5000 shocks at week 0 and 3000 at weeks 2 and 3, which was repeated 3 weeks later. Patients who completed sham treatment were unblinded and crossed over to the opposite arm for active treatment.

At weeks 20 and 32, the researchers assessed changes in gray-scale ultrasound erectile tissue homogeneity of the corpora cavernosa using visual grading scores as well as changes in color Duplex Doppler ultrasound assessments of artery blood flow parameters between baseline and follow-up.

Better Blood Flow – But Is That Enough?

After shock-wave therapy, more men experienced either improvements in or no worsening of blood flow parameters relative to baseline than after sham treatment. The decrease in end-diastolic volume was statistically significant for men in the active treatment arm 2 at week 32 (P = .003), according to the researchers.

The number of men whose visual grading scores for ultrasound gray-scale images improved in the proximal region was consistently higher with active treatment than with placebo (arm 1: 88.9% vs 11.1%; arm 2: 40% vs 20%), with statistical significance in arm 1 at weeks 20 (P = .005) and 32 (P = .001). Patients who received sham treatment and who subsequently received active shock-wave therapy also had improved scores on gray-scale ultrasound (arm 1: 33.3% vs 11.1%; arm 2: 40% vs 20%).

Scores on the International Index of Erectile Function (IIEF) were nominally higher for men in active treatment whose visual grading scores had improved compared with those who did not show improvement.

The most common adverse event was transient discomfort after the shock-wave treatment, according to the researchers.

Dr Irwin Goldstein

The study provides "a glimpse into the concept" that the mechanotransduction from a shock wave results in biochemical changes, including "activation of stem cells within the corpus cavernosum," said Irwin Goldstein, MD, the director of San Diego Sexual Medicine and clinical professor of surgery at the University of California, San Diego, who led the trial. "If I can activate stem cells," he added, "theoretically, I can improve the health of tissue."

Goldstein noted that the study is the first to use before-and-after objective gray-scale ultrasound imaging along with color Doppler ultrasound. "We could see gray scale changes and peak systolic velocity changes even with a small group," he said.

Goldstein added that the trial is the first in which zero energy was used in the sham phase instead of less energy than active treatment. With the sham treatment, there was no benefit on the gray scale, which he said is "very important."

He said his team is in the process of submitting a proposal for a larger prospective trial to confirm the findings.

Dr Louis Kuritzky

Although the results are promising, the study did not evaluate what matters most to men, said Louis Kuritzky, MD, a family medicine physician and assistant professor emeritus at HCA UCF Family Medicine Residency, in Gainesville, Florida.

"Men don't care what the flow velocity is ― they care [whether] they get an erection sufficient for penetration and completion of intercourse. That trial did not look at those endpoints. It looked at surrogates. Those are encouraging, but that's not what I think a clinician would base their decision upon about whether or not a patient should possibly participate in shock therapy."

Plasma Injections a Bust

The trial that assessed platelet-rich plasma was not encouraging. The results of the prospective, double-blind, randomized, placebo-controlled trial suggest that PRP is safe but not effective.

Dr Braian Ledesma

‌A proprietary version of the PRP injection is marketed as the "Priapus shot," or the "P-shot," despite a lack of solid evidence the therapy helps.

Brian Ledesma, MD, an andrology research fellow at the University of Miami, Florida, led the study, which received a "best abstract" award at the meeting. "We wanted to actually check and see ― does this work or not?" Ledesma said of PRP injections generally.

Ledesma and his colleagues randomly assigned 61 men with mild to moderate ED to receive two intracavernosal injections of PRP 1 month apart (n = 28) or placebo treatment (n = 33). The primary outcome was change in IIEF score and the percentage of men meeting minimum clinically important difference (MCID) at 1 month. Complete data were available for 24 men who received PRP and for 28 who received placebo injections.

There was no significant difference in outcomes between the groups. IIEF scores changed from 17.4 (95% CI, -15.8 to 19.0) to 21 (95% CI, 17.9 – 24.0) for men who received PRP and from 18.6 (95% CI, 17.3-19.8) to 21.6 (95% CI, 19.1-24.1) for men in the placebo group (P = .756). Fourteen men (58.3%) in the PRP group, compared to 15 (53.6%) in the placebo group, met MCID. No differences were seen in mean penile Doppler parameters between PRP and placebo. The two adverse events reported in the trial were minor ― a hematoma, and "a new plaque that did not cause any curvature of the penis," Ledesma said.

Platelet-rich plasma may be "really popular, but, objectively speaking, so far, we don't have any evidence showing that it actually works."

The study showed that "PRP was not more efficacious than placebo." This treatment is "really popular, but, objectively speaking, so far, we don't have any evidence showing that it actually works."

Based on these findings, he told Medscape Medical News, "We would recommend sticking to the data primary care providers should tell their patients, 'Don't waste your money,' because it's pretty expensive."

Kuritzky said more studies are needed for a definitive answer. "I think the results of PRP have been largely disappointing across most of the spheres of influence in which it's been tried. So, it's not so surprising to me that this trial would, again, not prove efficacious, but I'd have to hold judgment, dependent upon other trials," he said.

Ledesma and his colleagues are conducting a prospective, randomized, double-blind trial "investigating whether PRP combined with shock-wave therapy could make a difference." He said the trial, which is funded by the National Institutes of Health, is in the enrollment phase; results are expected in mid-2024 (ClinicalTrials.gov).

Charles Runels, MD, who pioneered the P-Shot and other popular cosmetic procedures, defended the effectiveness of the injections.

"One of the legitimate criticisms of all of the review articles regarding PRP therapies in every field is that there is a significant variability in what people call PRP. The P-Shot represents a very specific protocol in the methods of preparing PRP, activating PRP, and injecting the PRP — all of which differ significantly from what was done in Ledesma's study and which could account for their lack of results," Runels told Medscape Medical News.

Runels added that "multiple studies" do show benefit of the injection of PRP for both erectile dysfunction and Peyronie's disease and support the success of his protocol. "Also, all of our providers — there are over 3,000 people in our Cellular Medicine Association — offer money back to our patients if there are not satisfactory results," he said.

Kuritzky said that when patients ask him about investigational treatments for ED, he tells them to stick to the more traditional approaches, such as phosphodiesterase type 5 inhibitors, intracorporeal injections, and vacuum devices.

But, he added, if other therapies are shown to be safe and effective "in a large population of men with diverse etiologies associated with their erectile dysfunction, including advanced age, diabetes, dyslipidemia, hypertension, cigarette smoking, then I think [they] could be recommended on a more consistent basis."

Both studies were independently supported. Goldstein, Kuritzky, and Ledesma reported no relevant financial relationships.

American Urological Association (AUA) 2023 Annual Meeting: Abstract LBA01-12 and MP79-11. Presented April 30 and May 1, 2023.

Sarah Tilyou is a medical journalist in New York.

For more news, follow Medscape on Facebook, Twitter, Instagram, and YouTube.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.