Comparative efficacy and safety of phosphodiesterase type 5 inhibitors for erectile dysfunction in diabetic men: a Bayesian network meta-analysis of randomized controlled trials

An overview of conventional and investigational phosphodiesterase 5 inhibitors for treating erectile dysfunction and other conditions

INTRODUCTION

There is a rising concern about developing innovative, efficacious PDE5I molecules that provide better safety, efficacy, and tolerability with less adverse effects. Innovative PDE5I with dual targets have also been defined in the literature. Additionally, some of PDE5I are able to selectively inhibit other enzymes such as histone deacetylase, acetylcholine esterase, and cyclooxygenase or act as nitric oxide donors. This review presents knowledge concerning the advanced trends and perspectives in using PDE5I in treatment of ED and other conditions.

AREAS COVERED

Pre-clinical and early clinical trials that investigated the safety, efficacy, and tolerability of novel PDE5I such as Udenafil, Mirodenafil, Lodenafil, Youkenafil, Celecoxib, and TPN729 in treatment of ED and other conditions.

EXPERT OPINION

Preclinical and limited early clinical studies of the new molecules of PDE5I have demonstrated encouraging results; however, safety, efficacy, and tolerability are still issues that necessitate further long-term multicenter clinical studies to ensure justification of their uses in treatment of ED and other conditions. Progress in molecular delivery techniques and tailored patient-specific management and additional therapeutic technology will dramatically improve care for ED and other conditions. The dream of ED and many other conditions becoming more effectively managed may be feasible in the near future.

Differences in ocular adverse events associated with phosphodiesterase-5 inhibitors: a real-world pharmacovigilance study

OBJECTIVE

Our study aims to characterize the ocular safety profiles of phosphodiesterase type 5 (PDE5) inhibitors and explore the differences among different PDE5 inhibitors.

METHODS

We analyzed reports on ocular adverse events associated with sildenafil, vardenafil and tadalafil submitted to the FDA Adverse Event Reporting System (FAERS) database from the first quarter of 2004 to the first quarter of 2023. Disproportionality analysis was conducted to evaluate reporting risk profiles.

RESULTS

Among 61,211 reports qualifying for analysis, 5,127 involved sildenafil, 832 vardenafil, and 3,733 tadalafil. All PDE5 inhibitors showed increased reporting odds ratios (ROR) for ocular adverse events, with vardenafil highest (ROR 4.47) followed by sildenafil and tadalafil. Key ocular adverse events included cyanopsia, optic ischemic neuropathy, visual field defects, unilateral blindness and blindness. Sildenafil showed the highest disproportionality for cyanopsia (ROR 1148.11) while vardenafil and tadalafil showed the highest disproportionality for optic ischemic neuropathy. Time-to-onset analysis also revealed significant differences, with sildenafil having a later median time-to-onset compared to vardenafil and tadalafil.

CONCLUSIONS

This comprehensive pharmacovigilance study reveals distinct patterns of ocular adverse events associated with PDE5 inhibitors. These findings contribute to a better understanding of the safety profiles of PDE5 inhibitors and may guide healthcare professionals in clinical decision-making.

Nutritional aphrodisiacs: Biochemistry and Pharmacology

In 2022, the global prevalence of erectile dysfunction (ED) was estimated to be at least 150 million cases. This number is greatly suspected to be underestimate as most men withhold information about ED. Also, about 15% of world population have infertility troubles, and male factors are responsible for almost half of these cases. Studies have shown that the quality of semen has decreased in the past several decades owing to various health factors and environmental toxicants. The current medical interventions involve the inhibition of phosphodiesterase 5 which suffer from serious side effects and costly. One of the popular and most sought interventions are the natural and nutritional remedies as they are foods in essence and potentially with no harm to the body. Therefore, the goal of this paper is to provide a review of the most common nutritional aphrodisiacs with increasing libido and fertility highlighting the potential active constituents as well as the underlying mechanisms.

Erectile dysfunction and diabetes: A melting pot of circumstances and treatments

Diabetes mellitus (DM), a chronic metabolic disease characterised by elevated levels of blood glucose, is among the most common chronic diseases. The incidence and prevalence of DM have been increasing over the years. The complications of DM represent a serious health problem. The long-term complications include macroangiopathy, microangiopathy and neuropathy as well as sexual dysfunction (SD) in both men and women. Erectile dysfunction (ED) has been considered the most important SD in men with DM. The prevalence of ED is approximately 3.5-fold higher in men with DM than in those without DM. Common risk factors for the development of DM and its complications include sedentary lifestyle, overweight/obesity and increased caloric consumption. Although lifestyle changes may help improve sexual function, specific treatments are often needed. This study aims to review the definition and prevalence of ED in DM, the impact of DM complications and DM treatment on ED and, finally, the current and emerging therapies for ED in patients with DM.

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].

Effect of phosphodiesterase-type 5 inhibitors on erectile function: an overview of systematic reviews and meta-analyses

INTRODUCTION

Phosphodiesterase-type 5 inhibitors (PDE5i) are the recommended first-line treatment for erectile dysfunction. Previous systematic reviews and meta-analyses suggest that they are a safe and effective option in many patient groups. Similarly, PDE5i may be effective as part of combination therapy in non-responders to PDE5i. We will generate an overview of systematic reviews, meta-analyses and network meta-analyses aiming to summarise the available knowledge regarding the efficacy and safety of PDE5i in the general population and in multiple subgroups of patients.

METHODS AND ANALYSIS

This overview was designed in accordance with the PRIO-harms and Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines and its protocol was registered at PROSPERO. We will systematically search PubMed, Web of Science, Cochrane Library and Scopus databases from inception to November 2020 without any language restrictions. We will include systematic reviews or meta-analyses: (1) comparing the efficacy and safety of any dose of PDE5i with each other, with placebo or with other effective treatments for the management of erectile function; (2) exploring the use of any PDE5i alone or in combination with other treatment modalities in the general male population or in specific subgroups and (3) conducted with systematic procedures. Our overview will employ the AMSTAR 2 tool to evaluate the quality of the included studies and the Grading of Recommendations Assessment, Development and Evaluation approach to assess the strength of evidence for all outcomes. We will construct forest plots of risk estimates with the corresponding CI for all outcomes.

ETHICS AND DISSEMINATION

In this overview, we will undertake an extensive literature search in an attempt to evaluate the potential benefits and risks of treatment with one PDE5i versus another or versus placebo and provide recommendations for clinicians and policy-makers. No ethical approval is required.

PROSPERO REGISTRATION NUMBER

CRD42020216754.

Mirabegron improves erectile function in men with overactive bladder and erectile dysfunction: a 12-week pilot study

Phosphodiesterase type 5 inhibitors (PDE5i) is the only approved oral treatment for erectile dysfunction (ED) in the US, and alternative management remains necessary when this treatment fails or is contraindicated. Targeting other pathways than the NO-cGMP pathway and/or combining this approach with PDE5i may introduce new treatments for men who are unresponsive to PDE5i. This study aims to evaluate whether Mirabegron improves erectile function in men with concurrent overactive bladder and mild to moderate ED. Twenty subjects, 40-70 years old, registering International Index of Erectile Function (IIEF) score 11-25 and International Prostate Symptom Score 8-20, were treated with Mirabegron therapy for 12 weeks. Study participants were re-administered IIEF and OAB-q questionnaires on weeks 2, 4, 8, and 12 and assessed for adverse events. The primary and secondary endpoints were an increase in the IIEF-5 score of 4 units and a decrease in the Overactive Bladder questionnaire (OAB-q) symptom severity score of 10 units between study time points. Thirteen men completed the 12-week study. Mirabegron treatment improved the IIEF-5 scores in five patients (38.4%) by 4 points or more, whereas IIEF-5 scores were not affected by Mirabegron treatment in eight patients (61.5%). There were no clinically relevant decreases in the IIEF-5 score. Significant improvements were observed in intercourse satisfaction at week eight compared to baseline (p = 0.01). Orgasmic function and sexual desire were not affected by Mirabegron treatment. As expected, Mirabegron treatment reduced OAB symptoms based on OAB-q short form (p = 0.006) and OAB-q total health-related quality of life (HRQL) scores compared to baseline (p = 0.03). Residual bladder volumes were not affected by treatment. No serious side effects were reported during the study period. This study suggests that Mirabegron may improve both EF and OAB-related symptoms in some individuals without causing serious adverse events.

Erectile dysfunction and penile rehabilitation after pelvic fracture: a systematic review and meta-analysis

OBJECTIVE

To investigate the rate of erectile dysfunction (ED) after pelvic ring fracture (PRF).

DESIGN

Systematic review and meta-analysis.

METHODS

A systematic literature search of the Cochrane, EMBASE, MEDLINE, Scopus and Web of Science Library databases was conducted in January 2020. Included were original studies performed on humans assessing ED after PRF according to the 5-item International Index of Erectile Function (IIEF-5) questionnaire and fracture classification following Young and Burgess, Tile or Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association. Furthermore, interventional cohort studies assessing the effect of penile rehabilitation therapy with phosphodiesterase-5-inhibitors (PDE-5-I) on IIEF-5 scores compared before and after treatment were included. Results were presented as forest plots of proportions of patients with ED after PRF or mean changes on IIEF-5 questionnaires before and after penile rehabilitation. Studies not included in the quantitative analysis were narratively summarised. Risk of bias assessment was conducted using the revised tool for the Quality Assessment on Diagnostic Accuracy Studies.

RESULTS

The systematic literature search retrieved 617 articles. Seven articles were included in the qualitative analysis and the meta-analysis. Pooled proportions revealed 37% of patients with ED after suffering any form of PRF (result on probability scale pr=0.37, 95% CI: 0.26 to 0.50). Patients after 3 months of penile rehabilitation therapy reported a higher IIEF-5 score than before (change score=6.5 points, 95% CI: 2.54 to 10.46, p value=0.0013).

CONCLUSION

Despite some heterogeneity and limited high-quality research, this study concludes that patients suffering from any type of PRF have an increased risk of developing ED. Oral intake of PDE-5-I for the purpose of penile rehabilitation therapy increases IIEF-5 scores and may relevantly influence quality-of-life in these patients.

PROSPERO REGISTRATION NUMBER

CRD42020169699.

Effect of a three-piece inflatable penile prosthesis combined with a phosphodiesterase-5 inhibitor on erectile dysfunction

Objective

To investigate the therapeutic effect of implanting a three-piece inflatable penile prosthesis (IPP) combined with the phosphodiesterase-5 inhibitor sildenafil in severe erectile dysfunction (ED) patients.

Methods

This randomized controlled study included 123 ED patients. Sixty-two patients received the IPP implantation and 61 patients received the IPP implantation and the phosphodiesterase-5 inhibitor sildenafil. Erectile function and sexual life quality were evaluated using the five-item International Index of Erectile Function (IIEF) and modified Sexual Life Quality Questionnaire–Quality of Life domain (mSLQQ-QoL), respectively. Serum interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, vascular cell adhesion molecule (VCAM)-1, and intercellular adhesion molecule (ICAM)-1 levels were assessed. Kaplan–Meier curves were used to assess the overall IPP survival.

Results

Implantation of the three-piece IPP with sildenafil improved erectile function and sexual life quality, alleviated the inflammatory response, reduced the complication rate, and improved overall IPP survival.

Conclusion

Implantation of the three-piece IPP combined with a phosphodiesterase-5 inhibitor significantly improved clinical outcomes and the prognosis in ED patients.

Efficacy and Safety of Avanafil in Chinese Subjects With Erectile Dysfunction: A Multi-Center, Randomized, Double-Blinded, Placebo-Controlled Phase III Clinical Trial

Introduction

The incidence of erectile dysfunction (ED) increases with age in mainland China and phosphodiesterase 5 inhibitors (PDE5i) are the major drugs used for its treatment.

Aim

To determine the efficacy and safety of Chinese developed avanafil as therapy for ED in China.

Methods

This phase III trial was carried out in 7 medical centers in China. Eligible subjects suffering from ED were allocated randomly into 3 groups (ratio 1:1:1) and orally received a placebo, 100 or 200 mg avanafil for a total of 12 weeks.

Main outcome measures

The primary endpoint was changes in erectile function (EF) domain scores according to the International Index of EF (IIEF) questionnaire from baseline to week 12 of therapy. Secondary endpoints assessments were changes in the response rates of SEP, Q2 and Q3; changes in IIEF other domain scores. Safety evaluation monitored treatment-emergent adverse events (TEAEs), serious TEAEs, laboratory test results, vital signs and electrocardiographs.

Results

Of 218 randomized ED subjects, 182 (83.5%) completed the study. After 12-week therapy, alterations from baseline of the mean IIEF-EF domain scores in the 100 mg and 200 mg groups were greater than for the placebo (all P < .05) group. The changes in mean SEP Q2 response rates from baseline to week 12 in the placebo, 100 mg and 200 mg groups were 5.4%, 22.3% and 22.1%, and SEP Q3 response rate were 22.7%, 42.6% and 38.1%, respectively. Avanafil treatment (regardless of dose) improved EF vs placebo for most of other secondary efficacy endpoints studied (all P < .05). No differences were detected in efficacy endpoints between the 100 and 200 mg dosage groups (all P > .05) or in the incidence of TEAEs and drug-related TEAEs among the 3 groups (all P > .05).

Conclusion

Avanafil (100 or 200 mg) was effective and generally well tolerated in Chinese subjects with ED.

Jiang H, Lin H, Li F, et al. Efficacy and Safety of Avanafil in Chinese Subjects With Erectile Dysfunction: A Multi-Center, Randomized, Double-Blinded, Placebo-Controlled Phase III Clinical Trial. Sex Med 2021;9:100337.

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.

Practical Approaches to Treat ED in PDE5i Nonresponders

Erectile dysfunction (ED) is a common sexual disorder in adult males and one of the most important factors affecting their quality of life and that of their partners. Although PDE5 inhibitors (PDE5is) are the first choice for improving erectile function, there is a substantial proportion of ED patients, termed PDE5i nonresponders, who do not respond to PDE5is. Because of the lack of effective therapies, these patients always have serious social and psychological problems due to ED, which should be addressed. Here, we review the available literature about ED and PDE5is and propose several strategies for mitigating ED in PDE5i nonresponders.

Drug delivery options and therapeutic advances in the management of erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) is defined as the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It is estimated that 20-30% of adult men will have at least one episode of ED during their lifetime and the prevalence increases with age. ED is known to have significant negative psychological implications for men, resulting in impaired functional status and a greater prevalence of anxiety and depression.

AREAS COVERED

Medications for the treatment of erectile dysfunction largely revolve around oral, injection, and topical therapies. Though all three modalities are widely used, each delivery option has its own advantages and specific indications. Likewise, there are several new developing treatments for ED that may change the landscape of treatment. The goal of this review is to summarize contemporary drug delivery options used in the treatment of ED and highlight future promising pharmacological developments.

EXPERT OPINION

There are a myriad of new developments on the horizon including new PDE5Is and drug targets, nanotechnology enhancements, stem cell and gene therapy, shockwave therapy, and platelet-rich plasma injections. These are all promising new methods to not only treat ED but also to address the pathology and prevent or eliminate further damage.

Meta-Analysis of the Long-Term Efficacy and Tolerance of Tadalafil Daily Compared With Tadalafil On-Demand in Treating Men With Erectile Dysfunction

BACKGROUND

Erectile dysfunction (ED) is highly prevalent in aging men. Tadalafil daily and on-demand are widely used for the treatment of ED.

AIM

We performed a meta-analysis to evaluate the efficacy and safety of tadalafil daily compared with tadalafil on-demand in treating men with ED after at least 24 weeks of long-term treatment.

METHODS

Randomized controlled trials of tadalafil daily vs on-demand in treating men with ED were searched using MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. Systematic review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-analyses. The data was calculated by RevMan version 5.3.0. The references of related articles were also searched.

OUTCOMES

International Index of Erectile Function-Erectile Function domain, sexual encounter profile question 2 (SEP2), SEP question 3 (SEP3), any treatment-emergent adverse event (AE), discontinuation due to AEs, myalgia, back pain, headache, dyspepsia, and nasopharyngitis.

RESULTS

4 articles, including 1,035 participants were studied. The analysis found that tadalafil daily had a greater improvement than tadalafil on-demand in terms of International Index of Erectile Function-Erectile Function (mean difference (MD) 1.24; 95% CI 0.03-2.44; P = .04), SEP2 (MD 10.08; 95% CI 9.15-11.01; P < .00001) and SEP3 (MD 8.19; 95% CI 2.09-14.29; P = .009) in treating ED after at least 24 weeks treatment cycle. For safety, tadalafil on-demand had a higher incidence of any treatment-emergent AE (odds ratio 0.73; 95% CI 0.56-0.96; P = .02) compared with tadalafil daily, but for other aspects, including discontinuation due to AEs, myalgia, back pain, headache, dyspepsia, and nasopharyngitis, there were no significant difference between the 2 treatments.

CLINICAL IMPLICATIONS

Tadalafil daily may offer a better effect for ED than on-demand for long-term treatment.

STRENGTHS AND LIMITATIONS

From the perspective of evidence-based medicine, we evaluated the efficacy and safety of tadalafil daily compared with tadalafil on-demand in treating men with ED after a long-term treatment. The quality of these studies included is flawed, primarily in difference in tadalafil doses and severity of the ED.

CONCLUSION

Tadalafil daily provides a preferable therapeutic effect for ED with a lower incidence of treatment-emergent side effects relative to tadalafil on-demand after at least 24 weeks of long-term treatment. Zhou Z, Chen H, Wu J, et al. Meta-Analysis of the Long-Term Efficacy and Tolerance of Tadalafil Daily Compared With Tadalafil On-Demand in Treating Men With Erectile Dysfunction. J Sex Med 2019;7:282-291.

A Review of Current and Emerging Therapeutic Options for Erectile Dysfunction

Contemporary treatment algorithms for erectile dysfunction (ED) involve the use of medical therapies such as phosphodiesterase type 5 (PDE5) inhibitors and intracavernosal injection therapy of vasoactive agents, as well as vacuum erection devices and penile prosthesis implants in medically refractory cases. However, the current therapeutic options only address the symptoms of ED and not the underlying pathogenesis that results in ED. Newer and novel ED therapies aspire to reverse ED conditions by preventing cavernosal fibrosis, promoting endothelial revascularization and modulating various neuro-hormonal pathways. Regenerative therapeutic strategies such as low-intensity shock wave, gene and cellular-based therapies, and penile transplants are designed to improve penile hemodynamics and revitalize the cavernosal smooth muscle to mitigate and/or reverse underlying ED. This state-of-art article evaluates current and emerging therapeutic options for ED.