A 52-week multicenter randomized controlled study of the efficacy and safety of add-on dutasteride and imidafenacin to tamsulosin in patients with benign prostatic hyperplasia with remaining overactive bladder symptoms (DIrecT study)

Tamsulosin and Dutasteride Combination Therapy for Asian Men With Moderate-to-Severe Lower Urinary Tract Symptoms Secondary to Benign Prostatic Hyperplasia: A Systematic Review of Clinical Considerations That Influence the Prescription

The goal of combination therapy for moderate-to-severe lower urinary tract symptoms secondary to benign prostatic hyperplasia (LUTS/BPH) is to ease both the dynamic and static symptoms by using agents that have complementary mechanisms of action. Similar to prescribing other drugs, LUTS/BPH combination therapy has been affected by multiple factors. Previous qualitative research discussed the individual perspectives that influenced combination therapy administration. Yet, until recently, there has been limited interest in clinical reasons that physicians have to consider before prescribing LUTS/BPH combination treatment. This systematic review aimed to identify the clinical considerations that influence the decision to prescribe combination therapy of tamsulosin 0.4 mg + dutasteride 0.5 mg for Asian men with LUTS/BPH. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search was performed in databases Medline, CINAHL, the Cochrane Library, and Embase from inception until January 2024 using Medical Subject Headings (MeSH) terms and keywords with truncation for alternative acronyms. A citation search was performed to gather works of literature on LUTS/BPH combination treatment in addition to the "PICO" framework for search terms. Five English-language primary randomized controlled trials (RCTs) were included in the narrative analysis using the Critical Appraisal Skills Program (CASP) checklist after critical appraisal. Several dosages of tamsulosin (0.2 mg and 0.4 mg) have been administered in LUTS/BPH combination treatment over the last few decades despite 0.2 mg tamsulosin being standardized as an effective regime in Asian countries. A remarkable correlation between prostate volume (PV) and prostate-specific antigen (PSA) was found in Asian men, which requires higher PSA secretion to enlarge each prostate unit and causes an increased risk of moderate-to-severe LUTS. Additionally, BPH baseline variables may lead to a different response to combination therapy, especially the PV and PSA differences. In conclusion, compared with Caucasian men, a significantly higher risk of moderate-to-severe LUTS was found in Asian men. Initiation of combination therapy, especially dutasteride, depends on a larger PV (≥ 30 mL); it is possible, therefore, that earlier PV and PSA examinations and baseline variables assessments ought to be performed by physicians before the combination therapy prescription. Alternative treatment options may be considered for a patient who prefers an active pattern of sexual activity during their BPH combined pharmacotherapy. These clinical considerations may influence the prescription of tamsulosin 0.4 mg + dutasteride 0.5 mg combination therapy for Asian men with moderate-to-severe LUTS/BPH. This study was registered on PROSPERO (CRD42024575528).

Medical Advancements in Benign Prostatic Hyperplasia Treatments

PURPOSE OF REVIEW

This review aims to identify and summarize the current literature on the most recent therapeutic agents and combination strategies for the medical management of lower urinary tract symptoms resulting from benign prostatic hyperplasia.

RECENT FINDINGS

The latest advancements in BPH therapy have been in combination strategies. Alpha blockers continue to be the mainstay of treatment, but research is exploring the synergistic benefits of combining them with 5-alpha reductase inhibitors (5-ARIs), phosphodiesterase-5 (PDE5) inhibitors, and beta-3 agonists. The alpha-blocker + 5-ARI combination remains ideal for enlarged, significantly reducing clinical progression risk compared to monotherapy. Alpha-blocker + PDE5 inhibitor combinations appear safe and potentially beneficial for men with concomitant erectile dysfunction; sildenafil might hold an edge over tadalafil based on limited data. Beta-3 agonists show synergistic effects with alpha blockers for residual storage symptoms, offering similar efficacy to anticholinergics but with a better side effect profile.

Triple Therapy with Tamsulosin, Dutasteride, and Imidafenacin for Benign Prostatic Hyperplasia in Patients with Overactive Bladder Symptoms Refractory to Tamsulosin: Subgroup Analyses of the DIrecT Study

AIM

To verify if the efficacy of the triple therapy with tamsulosin, dutasteride, and imidafenacin (TDI) is influenced by any background characteristics in patients with overactive bladder (OAB).

METHODS

A subanalysis of data from the DIrecT study was conducted. Superiority of TDI over tamsulosin and dutasteride in terms of efficacy based on the Overactive Bladder Symptom Score (OABSS), total International Prostate Symptom Score (IPSS), IPSS quality of life index, and postvoid residual (PVR) was evaluated in binary subgroups.

RESULTS

In the treatment groups, there was a significant interaction of total OABSS with testosterone level (≥4.8 vs. <4.8 ng/mL, p = 0.043) and PVR (≥20 vs. <20 mL, p = 0.018). For the total IPSS, no significant interaction was found except for the IPSS QOL index. For the IPSS QOL index, a significant interaction was found with testosterone level (≥4.8 vs. <4.8 ng/mL, p < 0.0001) as well as with total IPSS and total OABSS. For the PVR, no significant interaction was found except with total OABSS.

CONCLUSIONS

Triple therapy with TDI is suggested to be a therapeutic option for benign prostatic hyperplasia in patients with residual OAB symptoms refractory to tamsulosin and in patients with various background characteristics regardless of severity of OAB symptoms. Trial Registry No. UMIN 000011980.

Meta-Analysis of the Efficacy and Safety of Imidafenacin for Overactive Bladder Induced by Benign Prostatic Hyperplasia in Men Receiving Alpha-Blocker Therapy

Purpose

The aim of this meta-analysis was to evaluate the efficacy and safety of imidafenacin for overactive bladder (OAB) induced by benign prostatic hyperplasia (BPH) in men receiving alpha-blocker monotherapy.

Methods

We performed a systematic research of the PubMed, Embase, and Cochrane Library databases, and searched for studies about alpha-blocker with or without imidafenacin treatment for OAB in patients with BPH. We also investigated the original references of the included texts.

Results

Four randomized controlled trials including 779 participants with BPH (389 in the alpha-blocker+imidafenacin group and 390 in the alpha-blocker only group) were studied. The main efficacy endpoint was the Overactive Bladder Symptom Score, which showed a mean difference of -1.88 (95% confidence interval, -2.32 to -1.44; P<0.00001), suggesting that alpha-blocker and imidafenacin treatment was effective in treating men with OAB. As other primary efficacy end points, the International Prostate Symptom Score (IPSS) total score (P=0.47), the IPSS storage symptom score (P=0.07), the IPSS voiding symptom score (P=0.60), and the IPSS quality of life score (P=0.18) indicated that 2 methods had no significant differences in treating men with OAB. In terms of safety, which was assessed using postvoid residual volume (P=0.05) and maximum flow rate (P=0.53), the analysis suggested that combination treatment was very well tolerated.

Conclusions

This study suggested that imidafenacin plus alpha-blocker was an efficacious and safe treatment for OAB symptoms in BPH patients.

A randomized controlled study of the efficacy of tadalafil monotherapy versus combination of tadalafil and mirabegron for the treatment of persistent overactive bladder symptoms in men presenting with lower urinary tract symptoms (CONTACT Study)

Aim

To evaluate efficacy and safety of combination of tadalafil + mirabegron for overactive bladder/benign prostatic hyperplasia (OAB/BPH).

Methods

Male patients with lower urinary tract symptoms (50 to 89 years), with remaining OAB symptoms even after administering tadalafil for more than 8 weeks were randomly assigned to either tadalafil monotherapy group (5 mg/day) or tadalafil/mirabegron combination therapy group (5 mg/50 mg/day). The primary endpoint was change from baseline in total OAB symptom score (OABSS) at week 12. The secondary endpoints were changes in International Prostate Symptom Score (IPSS), NIH‐chronic prostatitis symptom index (NIH‐CPSI), and micturition chart parameters at weeks 4 and 12.

Results

A total of 176 patients were randomized to either monotherapy (87 patients) or combination therapy (89 patients). The baseline characteristics of patients in the two groups were similar. The total OABSS (95% confidence interval) of combination therapy was significantly decreased by 1.78 (1.05‐2.50) points compared with that of monotherapy (P < .001). Changes from baseline in OABSS nighttime voiding score, urgency score, urgency incontinence score, IPSS storage subscores, NIH‐CPSI total score, and numbers of voids, nighttime‐voids, and urgency episodes/day in micturition chart were significantly reduced in combination therapy (all P < .001). Patient‐reported outcome was significantly more satisfactory in combination therapy than in monotherapy (P < .001). One moderate adverse event (pain in hip joint) with hardly presumed causal relationship with therapy and seven mild adverse events were noted in monotherapy and combination therapy group, respectively.

Conclusions

The effect of tadalafil/mirabegron combination therapy on relieving OAB symptoms appeared to be greater than that of tadalafil monotherapy and can be safely used.

A 52-week multicenter randomized controlled study of the efficacy and safety of add-on dutasteride and imidafenacin to tamsulosin in patients with benign prostatic hyperplasia with remaining overactive bladder symptoms (DIrecT study)

Objective

The aim of this study was to examine the long‐term efficacy of combination of tamsulosin 0.2 mg + dutasteride 0.5 mg + imidafenacin 0.2 mg (TDI) therapy compared with tamsulosin + dutasteride (TD) therapy for 52 weeks in benign prostatic hyperplasia (BPH) patients with a prostate volume (PV) ≥30 mL and remaining overactive bladder (OAB) symptoms after having received tamsulosin for ≥8 weeks. Previously, we reported that the improvement in OAB symptoms at 24 weeks was significantly greater in the TDI than TD group.

Methods

BPH patients with OAB symptoms after ≥8 weeks tamsulosin were randomly assigned to the TDI or TD group in a ratio of 1:1 ratio, and followed‐up for 52 weeks. Changes in the OAB Symptom Score (OABSS), International Prostate Symptom Score (IPSS), and post‐void residual (PVR) were evaluated.

Results

In all, 163 patients were randomized, and 125 patients (76.7%) completed 52 weeks of treatment. At Week 52, there were significant decreases in the OABSS and IPSS storage subscore compared with baseline in the TDI versus TD group, but the change in the total IPSS did not differ significantly between the two groups. There was no change in PVR from Week 24 to Week 52 in either group.

Conclusions

For BPH patients with PVR ≥30 mL and remaining storage symptoms despite tamsulosin monotherapy, TDI treatment showed better results in terms of improved OAB symptoms than TD treatment up to 52 weeks.