Systematic Review of Oral Combination Therapy for Erectile Dysfunction When Phosphodiesterase Type 5 Inhibitor Monotherapy Fails

Revisiting experimental models of erectile dysfunction and their value in drug discovery and development

INTRODUCTION

Erectile dysfunction (ED) is a common condition that often signals underlying endothelial dysfunction, although the underlying causative factor(s) are likely complex and multifactorial. Various animal models have been developed to provide a research platform to study ED and served as an important basis for the discovery and subsequent development of novel therapeutic drugs for ED.

AREAS COVERED

The review article provides an overview of various animal models in ED research with an emphasis on important drug target discovery relating to each specific experimental model. The authors highlight translation from basic science research to major preclinical and clinical studies in this evolving field of ED research.

EXPERT OPINION

Animal models simulate the pathological features of various types of ED and clarify their molecular mechanisms. These mechanisms aid in discovering drug targets, while established ED models also provide a basis for validating drug efficacy, safety, and specific action mechanisms. The development of techniques in detection methods, cellular experimental, and omics has a profound impact on disease prediction, model evaluation, and optimization of therapeutic modalities. On this basis, many drug therapies targeting these ED-related mechanisms, especially in the nitric oxide/cyclic guanosine monophosphate pathways have been applied in preclinical studies. However, focusing on drug development for those types of ED where phosphodiesterase 5 inhibitor therapy is limited may be more valuable.

The effect of topical and intraurethral alprostadil on erectile function: A systematic review and meta-analysis

BACKGROUND

Erectile dysfunction (ED) affects up to 50% of men over 40. While phosphodiesterase-5 inhibitors (PDE5i) are the first line of medical treatment, they are not always effective. Alprostadil, available in injectable, topical, and intraurethral forms, offers an alternative treatment modality.

OBJECTIVES

This systematic review and meta-analysis aim to evaluate the efficacy and safety of topical and intraurethral forms of alprostadil.

MATERIALS AND METHODS

The objectives and methods of this systematic review and meta-analysis were predefined in a protocol registered on PROSPERO (CRD42021260894). We systematically searched PubMed, EMBASE, and the Cochrane Library up to April 2024. Using a random-effects model, we compared the efficacy of topical and intraurethral forms of alprostadil against placebo. Additionally, we performed a qualitative assessment of the studies using RoB-2 and ROBINS-I tools.

RESULTS

The analysis included 11 randomized controlled trials and 4 non-randomized studies, encompassing 5869 patients with a mean age of 60 ± 9.4 years. The meta-analysis showed a statistically significant improvement in the IIEF score by 4.7 points (95% CI: 2.4-7.1, I2 = 97%) in patients using the topical form of alprostadil compared to placebo. There was also a statistically significant improvement of ED in patients using intraurethral alprostadil compared to placebo, with a pooled odds ratio of 0.08 (95% CI: 0.04-0.16, I2 = 54%). The most common adverse events reported were penile pain and erythema.

DISCUSSION

These results are limited by the variability in study designs and the relatively small number of included studies in the meta-analysis. Moreover, the low methodological quality of the included studies further limits the strength of the conclusions.

CONCLUSIONS

Topical and intraurethral alprostadil significantly improve ED symptoms compared to placebo and are generally safe, with no serious adverse events. Further trials are necessary to confirm and expand on these findings.

A novel reuptake inhibitor, IP2015, induces erection by increasing central dopamine and peripheral nitric oxide release

BACKGROUND AND PURPOSE

An estimated 40% of patients with erectile dysfunction have a poor prognosis for improvement with currently available treatments. The present study investigated whether a newly developed monoamine transport inhibitor, IP2015, improves erectile function.

EXPERIMENTAL APPROACH

We investigated the effects of IP2015 on monoamine uptake and binding, erectile function in rats and diabetic mice and the effect on corpus cavernosum contractility.

KEY RESULTS

IP2015 inhibited the uptake of 5-HT, noradrenaline and dopamine by human monoamine transporters expressed in cells and in rat brain synaptosomes. Intracavernosal pressure measurement in anaesthetized rats revealed that IP2015 dose-dependently increased the number and the duration of spontaneous erections. Whereas pretreatment with the dopamine D2-like receptor antagonists, clozapine and (-)-sulpiride, or cutting the cavernosal nerve inhibited IP2015-induced erectile responses, the phosphodiesterase type 5 inhibitor sildenafil further enhanced the IP2015-mediated increase in intracavernosal pressure. IP2015 also increased the number of erections in type 2 diabetic db/db mice. Direct intracavernosal injection of IP2015 increased penile pressure, and in corpus cavernosum strips, IP2015 induced concentration-dependent relaxations. These relaxations were enhanced by sildenafil and blunted by endothelial cell removal, a nitric oxide synthase inhibitor, NG-nitro-l-arginine and a D1-like receptor antagonist, SCH23390. Quantitative polymerase chain reaction (qPCR) showed the expression of the dopamine transporter in the rat corpus cavernosum.

CONCLUSION AND IMPLICATIONS

Our findings suggest that IP2015 stimulates erectile function by a central mechanism involving dopamine reuptake inhibition and direct NO-mediated relaxation of the erectile tissue. This novel multi-modal mechanism of action could offer a new treatment approach to erectile dysfunction.

The effect of combination treatment with low-intensity shockwave therapy and daily tadalafil on severe erectile dysfunction: a double-blind, randomized, sham-controlled clinical trial

BACKGROUND

Patients with severe erectile dysfunction (ED) remain the most challenging group in terms of available noninvasive treatment modalities.

AIM

The study sought to assess the role of combination therapy with low-intensity shockwave therapy (LiST) and daily tadalafil 5 mg in a highly select group of patients with severe vasculogenic ED through a double-blind, randomized trial.

METHODS

Forty-eight sexually active men were randomly assigned to 12 sessions of LiST 3 times weekly and tadalafil 5 mg once daily (n = 34) or sham therapy and tadalafil (n = 17) for 4 weeks. Patients were assessed at 1 and 3 months after completion of treatment.

OUTCOMES

Improvement of erectile function was evaluated through the International Index of Erectile Function-Erectile Function domain (IIEF-EF) or 6-item IIEF and the Sexual Encounter Profile (SEP) diary. The primary outcome was the difference between the groups in the IIEF-EF at 3 months after completion of treatment. Secondary outcomes comprised (1) the difference between the groups in the IIEF-EF at 1 month after completion of treatment, (2) the difference between the groups in the "yes" responses to question 3 of the SEP diary at 1 and 3 months, and (3) the treatment-related adverse events. The number of patients attaining a minimal clinically important difference in the IIEF-EF (improvement of at least 7 points) was also assessed.

RESULTS

After treatment, the absolute scores in the IIEF-EF were higher in patients receiving LiST and tadalafil vs sham therapy and tadalafil both at the 1-month (12.1 ± 2.4 vs 10.2 ± 1.7; P = .002) and at the 3-month (12.9 ± 2.1 vs 10.8 ± 1.8; P < .001) evaluation. Between the 2 groups, the proportion of "yes" responses to question 3 of the SEP diary was not statistically significant, whereas the number of patients attaining a minimal clinically important difference in the IIEF-EF was statistically significant only at the 3-month evaluation. No adverse events occurred.

CLINICAL IMPLICATIONS

Application of LiST in patients with severe vasculogenic ED receiving daily dose tadalafil may further improve erectile function compared with tadalafil as a stand-alone treatment on the short term.

STRENGTHS AND LIMITATIONS

Although we provided the first study in the field, severe vasculogenic ED was defined based on medical history and clinical examination and not based on penile ultrasound measures.

CONCLUSION

The combination of 12 sessions LiST 3 times weekly and daily tadalafil for 4 weeks led to a 2-point difference in the IIEF-EF compared with sham therapy and daily tadalafil among patients with severe vasculogenic ED after 1 and 3 months from completion of treatment.

Corpora cavernosa fibroblasts mediate penile erection

Penile erection is mediated by the corpora cavernosa, a trabecular-like vascular bed that enlarges upon vasodilation, but its regulation is not completely understood. Here, we show that perivascular fibroblasts in the corpora cavernosa support vasodilation by reducing norepinephrine availability. The effect on penile blood flow depends on the number of fibroblasts, which is regulated by erectile activity. Erection dynamically alters the positional arrangement of fibroblasts, temporarily down-regulating Notch signaling. Inhibition of Notch increases fibroblast numbers and consequently raises penile blood flow. Continuous Notch activation lowers fibroblast numbers and reduces penile blood perfusion. Recurrent erections stimulate fibroblast proliferation and limit vasoconstriction, whereas aging reduces the number of fibroblasts and lowers penile blood flow. Our findings reveal adaptive, erectile activity-dependent modulation of penile blood flow by fibroblasts.

Oxidized soluble guanylyl cyclase causes erectile dysfunction in alcoholic mice

BACKGROUND AND PURPOSE

Alcohol abuse has been associated with erectile dysfunction (ED), but the implicated molecular mechanisms are unresolved. This study analyses the role of alterations in soluble guanylyl cyclase (sGC) in ED.

EXPERIMENTAL APPROACH

ED was analysed in adult male C57BL/6J mice subjected to the Chronic Intermittent Ethanol (CIE) paradigm. Erectile function was assessed in anaesthetised mice in vivo by evaluating intracavernosal pressure (ICP) and in vitro in isolated mice corpora cavernosa (CC) mounted in a myograph. Protein expression and reactive oxygen species were analysed by western blot and dihydroethidium staining, respectively.

KEY RESULTS

In CIE mice, we observed a significant decrease in the relaxant response of the CC to stimulation of NO release from nitrergic nerves by electrical field stimulation, to NO release from endothelial cells by acetylcholine, to the PDE5 inhibitor sildenafil, and to the sGC stimulator riociguat. Conversely, the response to the sGC activator cinaciguat, whose action is independent of the oxidation state of sGC, was significantly enhanced in these CC. The responses to adenylyl cyclase stimulation with forskolin were unchanged. We found an increase in reactive oxygen species in the CC from CIE mice as well as an increase in CYP2E1 and NOX2 protein expression. In vivo pre-treatment with tempol prevented alcohol-induced erectile dysfunction.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrate that alcoholic mice show ED in vitro and in vivo due to an alteration in the redox state of sGC and suggest that sGC activators may be effective in ED associated with alcoholism.

Combination therapy with topical alprostadil and phosphodiesterase-5 inhibitors after failure of oral therapy in patients with erectile dysfunction: a prospective, two-arm, open-label, non-randomized study

Phosphodiesterase type 5 inhibitors (PDE5Is) are the first-line therapeutic option for erectile dysfunction (ED), while second-line therapy includes the alprostadil. Due to the different pharmacodynamic mechanism of PDE5Is and alprostadil, a synergistic action is conceivable when they are administered in combination. The aim of present study was to evaluate the efficacy and safety of combination therapy with PDE5I and topical alprostadil in patients with ED non-responders to PDE5I alone. We designed a prospective, two-arm, open-label, non-randomized study. Patients over 18 years old, with a stable sexual relationship for at least 6 months, and ED non-responders to PDE5I monotherapy were included in the study. At baseline the variables assessed were 5-item version of the International Index of Erectile Function (IIEF-5), and Sexual Encounter Profile Questions 2 and 3 (SEP-2 and SEP-3). In addition, all subjects underwent penile dynamic duplex ultrasonography. All patients were assigned to the monotherapy group (Group A) or combination therapy group (Group B) based on their preference. Topical alprostadil 300 μg/100 mg (Virirec®) was the treatment assigned to Group A, while the combination therapy with the last PDE5I taken (at the maximum recommended dose) plus topical alprostadil 300 μg/100 mg (Virirec®) was assigned to Group B. After 3 months from assignment to groups were evaluated IIEF-5, SEP-2 and SEP-3 regarding the last sexual intercourse, and Global Assessment Questionnaire-Questions 1 and 2 (GAQ-1 and GAQ-2). All adverse events (AEs) that occurred during the study period were recorded. A total of 170 patients were included in the study (72 in Group A and 98 in Group B). Fifty-two patients were previously treated with sildenafil 100 mg (30.6%), 6 with vardenafil 20 mg (3.5%), 56 with tadalafil 20 mg (32.9%), and 56 with avanafil 200 mg (32.9%). No significant differences among the study groups were found at baseline (p > 0.05). The mean IIEF-5 score increased significantly in Group B after treatment compared to baseline (12.4 ± 3.4 vs. 17.1 ± 4.5; p < 0.001), conversely patients in Group A showed no significant increase (12.2 ± 2.5 vs. 12.7 ± 3.1; p = 0.148). The number of affirmative responses to SEP-2 was significantly higher after treatment compared to baseline only in Group B (57 vs. 78; p < 0.001). The number of affirmative responses to SEP-3 was significantly higher after treatment compared to baseline in both groups (p < 0.001). The number of affirmative responses to GAQ-Q1 and GAQ-Q2 was significantly higher in Group B compared to Group A (p < 0.001). A total of 59 (34.7%) patients experienced AEs. They were mild, self-limited, and did not cause discontinuation of treatment. No episode of priapism was recorded. No statistically significant difference was recorded between the AEs of the two groups, except for facial flushing that was reported only in Group B (p = 0.021). The combination therapy with topical alprostadil and PDE5I seems to be more effective than topical alprostadil alone without worsening the safety of the treatment.

Transcription factor gene Pea3 regulates erectile function during copulation in mice

Male mice with homozygous loss of function mutations of the transcription factor gene Pea3 (Pea3 null) are infertile due to their inability to inseminate females, however the specific deficits in male sexual behaviors that drive this phenotype are unknown. Here, the copulatory behavior of male mice (Pea3 null and control) with hormonally primed ovariectomized females was monitored via high-speed and high-resolution digital videography to assess for differences in female-directed social behaviors, gross sexual behaviors (mounting, thrusting), and erectile and ejaculatory function. Pea3 null male mice exhibit greatly reduced erectile function, with 44% of males displaying no visible erections during copulation, and 0% achieving sustained erections. As such, Pea3 null males are incapable of intromission and copulatory plug deposition, despite displaying largely normal female-directed social behaviors, mounting behaviors, and ejaculatory grasping behavior. Additionally, the organization and timing of thrusting behaviors is impaired in Pea3 null males. Our results show that the transcription factor gene Pea3 regulates the ability to achieve and maintain erections during copulation in mice.

Long Term Effectiveness and Safety of Intracavernosal Botulinum Toxin A as an Add-on Therapy to Phosphosdiesterase Type 5 Inhibitors or Prostaglandin E1 Injections for Erectile Dysfunction

BACKGROUND

Some evidence suggests that intracavernosal botulinum toxin A (BTX-A IC) injections administered in addition to phosphodiesterase type 5 inhibitors (PDE5-Is) or prostaglandin E1 intracavernosal injections (PGE1 ICI) could effectively treat erectile dysfunction (ED) in non-responders, or insufficient responders to these pharmacologic treatments.

AIM

To determine the long-term effectiveness and safety of combined treatment involving a single injection of BTX-A IC as an add on therapy to PDE5-Is or PGE1-ICI for the treatment of ED of different etiologies.

METHODS

A retrospective, uncontrolled, single center study was conducted. Data from 123 consecutive patients with ED who were insufficient responders to PDE5-Is or PGE1-ICI and who received onabotulinumtoxinA 100 U, abobotulinumtoxinA 250 U or 500 U IC as an add on to their current pharmacologic treatment were analyzed. All analyses were exploratory. Qualitative data were compared using the Fisher's exact test. Univariate and multivariate analysis were performed using logistic regression with Odds Ratios (OR). Only variables with P < .05 in the univariate analysis were selected for multivariate analysis.

RESULTS

The minimally clinically important difference (relative to baseline severity of ED) in the International Index of Erectile Function-Erectile function domain (IIEF-EF) score was achieved in 50% of patients at 34 (27-42) days and in 41% at 5.9 (3.9 - 8.1) months following BTX-A IC in combination with PDE5-Is or PGE1 ICI. The severity of ED influenced response to BTX-A IC according to the multivariate analysis (OR = 0.3, IC(95%]) = (0.16 - 0.56). Neither being post prostatectomy nor the type of BTX-A affected the response. Effectiveness tended to decrease more over time with abobotulinumtoxinA 250 U than 500 U.The only side-effects were mild penile pain on injection (n = 1) and mild penile pain for 3 days following injection (n = 1); no systemic effects were reported.

CLINICAL IMPLICATIONS

BTX-A IC (all types) administered as an add on to registered pharmacologic treatments improved erectile function for at least 6 months in 41% of patients with ED of varying etiologies, and was safe.

STRENGTHS & LIMITATIONS

A relatively large cohort of patients with ED was included, with a long follow-up period, however the study was retrospective, and uncontrolled.

CONCLUSION

This study provides preliminary evidence that BTX-A IC administered as an add-on therapy for ED that is insufficiently responsive to standard therapy is effective for at least 6 months, and is safe. Randomized clinical trials are now needed to fully confirm these results.

The Effect of Combination Treatment with Low-Intensity Shockwave Therapy and Tadalafil on Mild and Mild-To-Moderate Erectile Dysfunction: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial

BACKGROUND

Combination of different first-line treatments for erectile dysfunction (ED) has emerged as a promising therapeutic approach.

AIM

To conduct the first double-blind, randomized, placebo-controlled clinical trial to evaluate the efficacy and safety of combination therapy with low-intensity shockwave therapy (LiST) and tadalafil vs LiST and placebo in patients with mild or mild-to-moderate vasculogenic ED.

METHODS

Fifty sexually active patients fulfilling the eligibility criteria were randomly assigned to 6 sessions of LiST twice weekly for 3 weeks and tadalafil (n = 25) or placebo (n = 25) once daily for 4 weeks. Patients were evaluated at 1, 3, and 6 months after completion of the treatment protocol.

OUTCOMES

The primary outcome was the mean change from baseline in the International Index of Erectile Function-Erectile Function (IIEF-EF) domain between the 2 groups at 3 months after treatment. Erectile function was also assessed at 1 and 6 months. The number of patients attaining a minimal clinically important difference (MCID) in the IIEF-EF, as well as the safety of combination therapy were evaluated.

RESULTS

Adjusting for the baseline values, IIEF-EF improved by 0.8 points more (95% confidence interval [CI] = -0.2 to 1.9, P = .12) at 1 month, 1 point more (95% CI = 0.1-1.9, P = .02) at 3 months and 1.7 points more (95% CI = 0.8-2.7, P < .001) at 6 months in patients treated with combination therapy compared to monotherapy. The number of patients attaining a MCID in the IIEF-EF between the 2 groups improved significantly only at the 3-month evaluation. No adverse events were reported during the whole study period.

CLINICAL IMPLICATIONS

Combination of LiST twice weekly for 3 weeks and tadalafil 5 mg once daily for 4 weeks may further ameliorate mild or mild-to-moderate vasculogenic ED compared to LiST monotherapy.

STRENGTHS & LIMITATIONS

We conducted the first randomized trial exploring the role of LiST and tadalafil in the management of ED. Conversely, our study lacks external validity due to its single-center design.

CONCLUSION

The addition of daily low-dose tadalafil during application of LiST may further improve erectile function compared to application of LiST as a standalone treatment in patients with mild or mild-to-moderate vasculogenic ED. Still, further high-quality studies are warranted to corroborate our findings.

The Effect of Metformin on Male Reproductive Function and Prostate: An Updated Review

Metformin is the first-line oral antidiabetic drug that shows multiple pleiotropic effects of anti-inflamation, anti-cancer, anti-aging, anti-microbia, anti-atherosclerosis, and immune modulation. Metformin's effects on men's related health are reviewed here, focusing on reproductive health under subtitles of erectile dysfunction (ED), steroidogenesis and spermatogenesis; and on prostate-related health under subtitles of prostate specific antigen (PSA), prostatitis, benign prostate hyperplasia (BPH), and prostate cancer (PCa). Updated literature suggests a potential role of metformin on arteriogenic ED but controversial and contradictory effects (either protective or harmful) on testicular functions of testosterone synthesis and spermatogenesis. With regards to prostate-related health, metformin use may be associated with lower levels of PSA in humans, but its clinical implications require more research. Although there is a lack of research on metform's effect on prostatitis, it may have potential benefits through its anti-microbial and anti-inflammatory properties. Metformin may reduce the risk of BPH by inhibiting the insulin-like growth factor 1 pathway and some but not all studies suggest a protective role of metformin on the risk of PCa. Many clinical trials are being conducted to investigate the use of metformin as an adjuvant therapy for PCa but results currently available are not conclusive. While some trials suggest a benefit in reducing the metastasis and recurrence of PCa, others do not show any benefit. More research works are warranted to illuminate the potential usefulness of metformin in the promotion of men's health.

The Effect of Phosphodiesterase-type 5 Inhibitors on Erectile Function: An Overview of Systematic Reviews

Background: Multiple systematic reviews explore the effect of phosphodiesterase type 5 (PDE5) inhibitors on erectile dysfunction (ED), with each study addressing specific outcomes. However, physicians and policymakers require a holistic approach of this topic.

Objective: To summarize the current evidence regarding the efficacy and safety of PDE5 inhibitors for the management of ED through an overview of systematic reviews.

Methods: Studies were identified by searching PubMed, Web of Science, Cochrane Library and Scopus databases, as well as sources of grey literature until June 12, 2021 (PROSPERO: CRD42020216754). We considered systematic reviews, meta-analyses or network meta-analyses of randomized trials that provided outcomes about the efficacy and safety of any approved PDE5 inhibitor (avanafil, sildenafil, tadalafil and vardenafil). We constructed forest plots for meta-analytic effects regarding the change in erectile function, adverse events and dropouts after administration of PDE5 inhibitors in the general population and in specific patient groups.

Results: We included 23 studies with 154,796 participants and a total of 258 meta-analytic effects. Sildenafil 25 mg [Weighted Mean Difference (WMD): 13.08, 95% Confidence Interval (CI): 10.1-16.06] seemed to be statistically superior to all interventions in improving erectile function compared to placebo, but studies with low-dose sildenafil are lacking. Moreover, comparing among different PDE5 inhibitors, sildenafil 50 mg or sildenafil 100 mg were considered the most effective compounds in the general population. The latter derived, however, predominantly from indirect comparisons among different PDE5 inhibitors. Still, sildenafil 100 mg was associated with more treatment-related adverse events and dropouts. Interestingly, low-dose daily tadalafil may be more effective than high-dose on-demand tadalafil (WMD: 1.24, 95% CI: 0.03-2.44). Furthermore, testosterone and PDE5 inhibitors in patients with ED and hypogonadism seem to further improve symptoms, while the addition of a-blockers in patients with urinary symptoms treated with PDE5 inhibitors does not provide additional benefits (WMD: −0.8, 95% CI: −1.65-0.06).

Conclusion: Although the efficacy and safety of PDE5 inhibitors, compared to placebo, is well-documented, the existing evidence comparing different PDE5 inhibitors is low. Therefore, high-quality, head-to-head, trials comparing different PDE5 inhibitors are necessary to determine their ideal dosage and formulation based on their safety and efficacy profile.

Systematic Review Registration: PROSPERO, identifier [CRD42020216754].

Assessment of Combination Therapies vs Monotherapy for Erectile Dysfunction: A Systematic Review and Meta-analysis

IMPORTANCE

Combining 2 first-line treatments for erectile dysfunction (ED) or initiating other modalities in addition to a first-line therapy may produce beneficial outcomes.

OBJECTIVE

To assess whether different ED combination therapies were associated with improved outcomes compared with first-line ED monotherapy in various subgroups of patients with ED.

DATA SOURCES

Studies were identified through a systematic search in MEDLINE, Cochrane Library, and Scopus from inception of these databases to October 10, 2020.

STUDY SELECTION

Randomized clinical trials or prospective interventional studies of the outcomes of combination therapy vs recommended monotherapy in men with ED were identified. Only comparative human studies, which evaluated the change from baseline of self-reported erectile function using validated questionnaires, that were published in any language were included.

DATA EXTRACTION AND SYNTHESIS

Data extraction and synthesis were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

MAIN OUTCOMES AND MEASURES

A meta-analysis was conducted that included randomized clinical trials that compared outcomes of combination therapy with phosphodiesterase type 5 (PDE5) inhibitors plus another agent vs PDE5 inhibitor monotherapy. Separate analyses were performed for the mean International Index of Erectile Function (IIEF) score change from baseline and the number of adverse events (AEs) by different treatment modalities and subgroups of patients.

RESULTS

A total of 44 studies included 3853 men with a mean (SD) age of 55.8 (11.9) years. Combination therapy compared with monotherapy was associated with a mean IIEF score improvement of 1.76 points (95% CI, 1.27-2.24; I2 = 77%; 95% PI, -0.56 to 4.08). Adding daily tadalafil, low-intensity shockwave therapy, vacuum erectile device, folic acid, metformin hydrochloride, or angiotensin-converting enzyme inhibitors was associated with a significant IIEF score improvement, but each measure was based on only 1 study. Specifically, the weighted mean difference (WMD) in IIEF score was 1.70 (95% CI, 0.79-2.61) for the addition of daily tadalafil, 3.50 (95% CI, 0.22-6.78) for the addition of low-intensity shockwave therapy, 8.40 (95% CI, 4.90-11.90) for the addition of a vacuum erectile device, 3.46 (95% CI, 2.16-4.76) for the addition of folic acid, 4.90 (95% CI, 2.82-6.98) for the addition of metformin hydrochloride and 2.07 (95% CI, 1.37-2.77) for the addition of angiotensin-converting enzyme inhibitors. The addition of α-blockers to PDE5 inhibitors was not associated with improvement in IIEF score (WMD, 0.80; 95% CI, -0.06 to 1.65; I2 = 72%). Compared with monotherapy, combination therapy was associated with improved IIEF score in patients with hypogonadism (WMD, 1.61; 95% CI, 0.99-2.23; I2 = 0%), monotherapy-resistant ED (WMD, 4.38; 95% CI, 2.37-6.40; I2 = 52%), or prostatectomy-induced ED (WMD, 5.47; 95% CI, 3.11-7.83; I2 = 53%). The treatment-related AEs did not differ between combination therapy and monotherapy (odds ratio, 1.10; 95% CI, 0.66-1.85; I2 = 78%). Despite multiple subgroup and sensitivity analyses, the levels of heterogeneity remained high.

CONCLUSIONS AND RELEVANCE

This study found that combination therapy of PDE5 inhibitors and antioxidants was associated with improved ED without increasing the AEs. Treatment with PDE5 inhibitors and daily tadalafil, shockwaves, or a vacuum device was associated with additional improvement, but this result was based on limited data. These findings suggest that combination therapy is safe, associated with improved outcomes, and should be considered as a first-line therapy for refractory, complex, or difficult-to-treat cases of ED.

An Analysis of a Commercial Database on the Use of Erectile Dysfunction Treatments for Men With Employer-Sponsored Health Insurance

OBJECTIVE

To investigate the annual erectile dysfunction (ED) prevalence among men enrolled in an employer-sponsored health insurance (ESHI) plan and evaluate ED treatment profiles among those with an ED diagnosis.

METHODS

A cross-sectional claims analysis was conducted using the IBM MarketScan Commercial Database, a nationally representative sample of US workers enrolled in ESHI plans. Patients aged 18-64 with at least one ED medical diagnosis claim and continuous enrollment in a given year between 2009 and 2017 were included. Among those with an ED diagnosis, utilization rates of the following ED treatments were determined: phosphodiesterase type 5 inhibitors (PDE5I), penile prosthesis implantation, other ED treatments (eg, vacuum pump, intraurethral suppositories), combination treatment, and no insurer-paid treatments.

RESULTS

Between 2009 and 2017, the annual prevalence of men with ESHI suffering from ED increased by 116%. However, in 2017, only 23% of men with an ED diagnosis received an ED therapy paid for by their ESHI plans. The proportion of men taking PDE5Is ranged from 18% in 2012 to 26% in 2015. The proportion of men with ED undergoing penile prosthesis implantation has declined in recent years (0.23% in 2009 to 0.11% in 2017). Similarly, the rate of men who received other ED treatments or combination treatment has decreased from 2009 to 2017 (0.94%-0.30% and 0.65%-0.19%, respectively).

CONCLUSION

ED prevalence among men insured by an ESHI plan has notably increased, yet approximately three-quarters of these men had no claims for ED treatments, indicating substantial access gaps to treatment.

Erectile dysfunction and cancer: current perspective

Erectile dysfunction (ED) is one of the major but underreported concerns in cancer patients and survivors. It can lead to depression, lack of intimacy between the couple, and impaired quality of life. The causes of erectile dysfunction are psychological distress and endocrinal dysfunction caused by cancer itself or side effect of anticancer treatment like surgery, radiotherapy, chemotherapy and hormonal therapy. The degree of ED depends on age, pre-cancer or pre-treatment potency level, comorbidities, type of cancer and its treatment. Treatment options available for ED are various pharmacotherapies, mechanical devices, penile implants, or reconstructive surgeries. A complete evaluation of sexual functioning should be done prior to starting anticancer therapy. Management should be individualized and couple counseling should be an integral part of the anticancer treatment.

The effect of cardiovascular morbidity on clinical response provided by tadalafil in patients with erectile dysfunction

We aimed to investigate the association between erectile dysfunction and severity of cardiovascular morbidity and to assess clinical responses to tadalafil of patients in different cardiovascular risk groups. Between November 2019 and August 2020, a total of 258 male patients aged 45-70 years with ED were included. They were divided into three groups according to the Framingham risk score: low-risk (n: 86, 33.3%), intermediate-risk (n: 103, 39.9%) and high-risk (n: 69, 26.8%). At admission, all domains of the International Index of Erectile Function score were worse in high-risk group compared to other risk groups (p < .001). After a 12-week follow-up, a more significant improvement was observed in all domains of erectile function in all risk groups, but high-risk group had lower sexual scores (p < .001). The lowest rate for complete responsiveness to tadalafil was observed in the high-risk group (37.7%). The rate of failure in complete responsiveness was found to be 4.127 times greater with higher Framingham score and 3.102 times greater with higher erectile dysfunction severity at admission. Our preliminary findings show that more severe sexual disorders are observed in high-risk patients with cardiovascular morbidity. Individualised treatment may be important in high-risk group since they may benefit less from tadalafil, and failure in complete responsiveness can be more common in this group.

Ionic Channels as Potential Therapeutic Targets for Erectile Dysfunction: A Review

Erectile dysfunction (ED) is a prevalent condition, especially in men over 40 years old, characterized by the inability to obtain and/or maintain penile erection sufficient for satisfactory sexual intercourse. Several psychological and/or organic factors are involved in the etiopathogenesis of ED. In this context, we gathered evidence of the involvement of Large-conductance, Ca2+-activated K+ channels (BKCa), Small-conductance, Ca2+-activated K+ channels (SKCa), KCNQ-encoded voltage-dependent K+ channels (KV7), Transient Receptor Potential channels (TRP), and Calcium-activated Chloride channels (CaCC) dysfunctions on ED. In addition, the use of modulating agents of these channels are involved in relaxation of the cavernous smooth muscle cell and, consequent penile erection, suggesting that these channels are promising therapeutic targets for the treatment of erectile dysfunction.

Cognitive Behavioral Sex Therapy: An Emerging Treatment Option for Nonorganic Erectile Dysfunction in Young Men: A Feasibility Pilot Study

Introduction

An increasing number of young men have been found to develop nonorganic erectile dysfunction (NOED) in recent years. The NOED has been shown to respond better to cognitive behavior sex therapy (CBST) in a few past studies.

Aim

The present research aims to establish the efficacy of CBST as a promising treatment option in young men suffering from NOED by administering a feasibility pilot trial.

Methods

28 young men (M = 31 years) out of a total of 39 men (7 excluded, 4 quit treatment) diagnosed with NOED from sexual health clinics in Pakistan were recruited to receive CBST treatment (n = 13) on average twice a week for a period of 50 minutes per session for a period of 4, 6, 8, and 12 weeks for the mild, mild to moderate, moderate, and severe forms of NOED, respectively, and sildenafil citrate group (n = 15) receiving sildenafil citrate 50 mg on demand. The trial design was sequential random assignment clinical trial.

Main Outcome Measures

International Index of Erectile Functoning-5 and Depression Anxiety Stress Scale-21 were used before treatment, after treatment, and in follow-up as the main outcome measures.

Results

The repeated measures analysis of covariance established a nonsignificant difference between CBST and sildenafil citrate 50 mg in NOED scores improvement, NOED severity reduction, and reduction in depression scores at posttreatment assessment. There were significant differences among different CBST modalities in improving NOED scores, reduction in NOED severity, and depression scores. There was significant difference in CBST and sildenafil citrate 50 mg in anxiety reduction at posttreatment assessment. The covariates age, age groups, and NOED duration did not significantly impact the treatment outcome for both treatment groups except age which impacted the interaction of treatment and anxiety scores.

Conclusion

The CBST is an emerging and promising treatment choice in younger men suffering from NOED.

Bilal A, Abbasi NuH. Cognitive Behavioral Sex Therapy: An Emerging Treatment Option for Nonorganic Erectile Dysfunction in Young Men: A Feasibility Pilot Study. J Sex Med 2020;8:396–407.