Clinical trial update on shockwave therapy and future of erectile function restoration

Proceedings of PRINCETON IV: PDE5 inhibitors and cardiac health symposium

INTRODUCTION

Prior consensus meetings have addressed the relationship between phosphodiesterase type 5 (PDE5) inhibition and cardiac health. Given significant accumulation of new data in the past decade, a fourth consensus conference on this topic was convened in Pasadena, California, on March 10 and 11, 2023.

OBJECTIVES

Our meeting aimed to update existing knowledge, assess current guidelines, and make recommendations for future research and practice in this area.

METHODS

An expert panel reviewed existing research and clinical practice guidelines.

RESULTS

Key findings and clinical recommendations are the following: First, erectile dysfunction (ED) is a risk marker and enhancer for cardiovascular (CV) disease. For men with ED and intermediate levels of CV risk, coronary artery calcium (CAC) computed tomography should be considered in addition to previous management algorithms. Second, sexual activity is generally safe for men with ED, although stress testing should still be considered for men with reduced exercise tolerance or ischemia. Third, the safety of PDE5 inhibitor use with concomitant medications was reviewed in depth, particularly concomitant use with nitrates or alpha-blockers. With rare exceptions, PDE5 inhibitors can be safely used in men being treated for hypertension, lower urinary tract symptoms and other common male disorders. Fourth, for men unresponsive to oral therapy or with absolute contraindications for PDE5 inhibitor administration, multiple treatment options can be selected. These were reviewed in depth with clinical recommendations. Fifth, evidence from retrospective studies points strongly toward cardioprotective effects of chronic PDE5-inhibitor use in men. Decreased rates of adverse cardiac outcomes in men taking PDE-5 inhibitors has been consistently reported from multiple studies. Sixth, recommendations were made regarding over-the-counter access and potential risks of dietary supplement adulteration. Seventh, although limited data exist in women, PDE5 inhibitors are generally safe and are being tested for use in multiple new indications.

CONCLUSION

Studies support the overall cardiovascular safety of the PDE5 inhibitors. New indications and applications were reviewed in depth.

Stem cell assisted low-intensity shockwave for erectile dysfunction treatment: Current perspective

Stem cell therapy and low-intensity extracorporeal shockwave (LI-ECSW) are recognized as potential restorative therapies and have been used in the treatment of erectile dysfunction (ED). Stem cell therapy is well-known due to its attributed regenerative ability and thus can help to improve erectile function in patients with vasculogenic ED. Besides, current evidence also shows that LI-ECSW therapy can help stimulate cell recruitment and proliferation and promote angiogenesis and vascularization in the damaged tissue. Hence, due to the therapeutic and restorative effects of both therapies, the success of ED treatment can be elevated through a combination therapy between stem cell therapy and LI-ECSW. In this review, a detailed description and efficacy discussion of combination therapies between different types of stem cells and LI-ECSW therapy are described. Besides, other potential cell types to use together with LI-ECSW are also listed in this review. Thus, this review provides better insight on the efficacy of combination therapy for ED treatment.

Stem-Cell, Shockwave, and Platelet Rich Plasma Therapy for the Treatment of Erectile Dysfunction and Peyronie's Disease: A Survey of Clinics Across the USA

OBJECTIVE

To identify clinics offering off-label therapies for erectile dysfunction (ED) and Peyronie's disease (Pyd) including stem cell, platelet-rich plasma (PRP), and shockwave therapy and to determine the transparency they provided to patients inquiring about these treatment modalities.

METHODS

Clinics were identified in different regions in the US using a systematic search on online website directories and were approached by asking a series of standardized questions regarding the cost of treatment, duration of therapy, the medical staff involved, and patient outcome data. A total of 26 clinics were surveyed for stem cell therapy, 26 for PRP treatment, and 27 for shockwave therapy.

RESULTS

Of the 79 clinics contacted, 93.7% provided some answers to the questions we asked, with a majority offering treatments for both ED and Pyd. The cost of treatment varied widely between clinics. The average cost per stem cell therapy injection was $5291, PRP per injection was $1336, and shockwave therapy per session was $413. A physician was involved in 67% of treatments, and only 6 of 79 clinics reported that a urologist was involved. Over 75% of the clinics reported patient satisfaction following treatment. Durability of benefits to patients ranged from months to years according to the clinics' reports.

CONCLUSION

Our data not only demonstrate the widespread use of off-label therapies for ED and PyD across the United States but also the lack of scientific data to support the claims made to patients. This study highlights the need for more oversight and standardization in novel regenerative therapies for ED and PyD.

Recent advances in stem cell therapy for erectile dysfunction: a narrative review

INTRODUCTION

While phosphodiesterase type 5 inhibitors (PDE5is) and others are used to treat Erectile dysfunction (ED), many patients are either unresponsive or resistant to it. Stem cell therapy (SCT) is a promising alternative approach. Numerous preclinical trials have demonstrated improved erectile function in animal models using SCT, although the number of clinical trials investigating SCT for men with ED is limited. Nonetheless, findings from human clinical trials suggest that SCT may be a useful treatment option.

AREAS COVERED

Biomedical literature, including PubMed, ClinicalTrials.gov, and European Union Clinical Trials Registry, were analyzed to summarize and synthesize information on stem cell therapy for ED in this narrative review. The achievements in preclinical and clinical evaluations are presented and critically analyzed.

EXPERT OPINION

SCT has demonstrated some benefits in improving erectile function, while further studies are urgently needed. Such studies would provide valuable insights into the optimal use of stem cell therapy and its potential as a therapeutic option for ED. Taking advantage of different mechanisms of action involved in various regenerative therapies, combination therapies such as SCT and low-energy shock waves or platelet-rich plasma may provide a more effective therapy and warrant further research.

A Comparative Feasibility Study for Transcranial Extracorporeal Shock Wave Therapy

The potential beneficial regenerative and stimulatory extracorporeal shock wave therapy (ESWT) applications to the central nervous system have garnered interest in recent years. Treatment zones for these indications are acoustically shielded by bones, which heavily impact generated sound fields. We present the results of high-resolution tissue-realistic simulations, comparing the viability of different ESWT applicators in their use for transcranial applications. The performances of electrohydraulic, electromagnetic, and piezoelectric transducers for key reflector geometries are compared. Based on density information obtained from CT imaging of the head, we utilized the non-linear wave propagation toolset Matlab k-Wave to obtain spatial therapeutic sound field geometries and waveforms. In order to understand the reliability of results on the appropriate modeling of the skull, three different bone attenuation models were compared. We find that all currently clinically ESWT applicator technologies show significant retention of peak pressures and energies past the bone barrier. Electromagnetic transducers maintain a significantly higher energy flux density compared to other technologies while low focusing strength piezoelectric applicators have the weakest transmissions. Attenuation estimates provide insights into sound field degradation and energy losses, indicating that effective transcranial therapies can readily be attained with current applicators. Furthermore, the presented approach will allow for future targeted in silico development and the design of applicators and therapy plans to ultimately improve therapeutic outcomes.

Energy-Based Therapies for Erectile Dysfunction: Current and Future Directions

Energy-based therapies are novel treatments for erectile dysfunction that are thought to work by stimulation of tissue vasodilation, neoangiogenesis, and so forth. Low-intensity extracorporeal shock wave therapy (Li-ESWT) is the energy-based therapy with the most robust evidence basis demonstrating efficacy and safety. Among this evidence, randomized controlled trials (RCTs) evaluating Li-ESWT have largely been focused on responders to phosphodiesterase-5 inhibitors. Many of these RCTs have limitations including short follow-up durations, inconsistent protocols, and small sample sizes. Until more diverse patient populations are studied and these limitations are addressed, the use of Li-ESWT should remain limited to IRB-approved clinical research trials.

Comparison of the efficacy and safety of low-intensity extracorporeal shock wave therapy versus on-demand sildenafil for erectile dysfunction

Background

Low-intensity extracorporeal shock wave therapy (Li-ESWT) is an effective therapy for erectile dysfunction (ED) but is not widely recognized and applied. This prospective nonrandomized study aimed to investigate the efficacy and safety of Li-ESWT.

Methods

After a 4-week washout period of past ED treatment, patients entered one of 2 active treatment groups, either 9-week Li-ESWT or 100 mg on-demand sildenafil. Patients were evaluated in the first- and third-month following initiation of treatment. The Li-ESWT protocol comprised 2 sessions per week for 3 weeks, which were repeated after a 3-week interval. Patients in the drug group took self-administered sildenafil at a dose of 100 mg before intercourse. The primary outcome was the effectiveness of Li-ESWT measured by the International Index of Erectile Function-5 (IIEF-5) scores. Other measurements included erection hardness score (EHS) and Self-Esteem And Relationship (SEAR).

Results

A total of 78 participants completed the study (46 in the Li-ESWT group and 32 in the sildenafil group). Overall, 26.9% of the participants (21/78) included were psychogenic. In the third month, the outcome measured by IIEF-5 was 21.52 in the Li-ESWT group and 21.26 in the sildenafil group (P>0.05). Proportion of improvement defined by minimal clinically important difference (MCID) criteria was 52.2% in the Li-ESWT group and 59.4% in the sildenafil group (P>0.05). The EHS and SEAR improvement was similar in the 2 groups (P>0.05 at baseline and third month). Transient and mild adverse events were observed in both groups.

Conclusions

In our study, a similar treatment efficacy and safety was shown by the application of Li-ESWT as on demand sildenafil.

Penile low intensity shock wave treatment for PDE5I refractory erectile dysfunction: a randomized double-blind sham-controlled clinical trial

PURPOSE

Over the last decade, penile low-intensity extracorporeal shockwave therapy (LI-ESWT) has emerged as a promising alternative for the treatment of erectile dysfunction (ED). The aim of this trial is to assess the effect of electromagnetic LI-ESWT on the erectile function of vascular phosphodiesterase type 5 inhibitor (PDE5I) refractory ED patients.

METHODS

Randomized, double-blind, sham-controlled study. 76 patients with vascular PDE5I-refractory ED completed the study. 40 men were treated with LI-ESWT (1 session/week for 4 weeks, 5000 shocks/session, 0.09 mJ/mm² energy density) and 36 were treated with a sham probe. Baseline and post-treatment (1, 3 and 6 months) evaluations were performed using validated erectile function questionnaires (IIEF-EF, EHS, SEP2, SEP3 and GAQ1). The groups were compared using Mann-Whitney-Wilcoxon and chi-squared tests, with results considered statistically significant at p < 0.05.

RESULTS

At the 3-month follow-up, median change in IIEF-EF score for active and sham groups was 3.5 (IQR 0-10) and - 0.5 (IQR - 11 to 1), respectively (p < 0.05). Six months after treatment, 52.5% of patients (21/40) in the active group and 27.8% of patients (10/36) in the sham group presented an EHS > 2 (p < 0.05). At the same evaluation, 40.0% (16/40) and 13.9% (5/36) of patients had positive answers to GAQ-1, in the treated and sham groups, respectively (p < 0.05). No adverse events were observed during the study.

CONCLUSION

This study showed that penile electromagnetic shockwave therapy may improve erectile function, to a modest extent, on certain patients that do not respond to PDE5I; making it an alternative for vascular ED patients that reject more invasive therapies.

Phase II Randomized, Clinical Trial Evaluating 2 Schedules of Low-Intensity Shockwave Therapy for the Treatment of Erectile Dysfunction

PURPOSE

To evaluate safety and clinical response of Low-intensity Shockwave Therapy (Li-SWT) for the treatment of erectile dysfunction.

MATERIALS & METHODS

A single-institution, 2 arm, phase II randomized clinical trial was conducted between February 2017 and April 2019. Patients were randomized into 2 groups, with Li-SWT delivering a total of 3,600 shocks over 5 days (720 once a day, Group A) or over 2 weeks (600 once a day, 3 times a week, Group B). Patients were evaluated for the safety of therapy and completed the International Index of Erectile Function-Erectile Function domain and the Erectile Hardness Scale assessment at baseline, and at 1, 3, and 6 months visits.

RESULTS

Among 87 evaluable patients, 45 and 42 were allocated to Groups A and B treatment schedules, respectively, and 80 patients (40 per group) completed the 6-month evaluation. No adverse events were reported during treatment or during follow-up. There were statistically significant (P < .05) improvements in International Index of Erectile Function-Erectile Function score (mean increase of 2.7 [95% CI = 1.2, 4.2] and 2.7 points [95% CI = 1.4, 4.1] for Groups A and B, respectively) and in Erectile Hardness Scale (mean increase of 0.6 points (95% CI = 0.3, 0.8) and 0.5 (95% CI = 0.2, 0.8) for Groups A and B, respectively) at 6 months, with no differences between groups.

CONCLUSION

No difference in outcomes was found when Li-SWT 3,600 shocks were delivered over 1 or 2 weeks at 6 months follow-up and both schedules were safe with no adverse events during or after treatment. Further trials with longer follow-up and sham arm will provide valuable information regarding treatment efficacy and durability. Patel P, Katz J, Lokeshwar SD, et al. Phase II Randomized, Clinical Trial Evaluating 2 Schedules of Low-Intensity Shockwave Therapy for the Treatment of Erectile Dysfunction. Sex Med 2020;8:214-222.