A Single-Arm, Dose Escalation of an Intraurethral Alprostadil Paste for Erectile Dysfunction

NCT07601646 | Recruiting Phase 2

• 1 other identifier: H25-00542
• Study Type: interventional
• Target: 83
• Locations: 1 country
• Sites: 1

Brief Summary

This is a single arm dose escalation trial of a mucoadhesive intraurethral polymer suspension of alprostadil (ST-04) and will investigate the efficacy of 3 dose levels of ST-04 in adult males with a clinical diagnosis of Erectile Dysfunction (ED). This study aims to determine if ST-04, with or without sildenafil, will improve erectile function (EF) compared to baseline. Participants in this study will receive ST-04, a new formulation containing the vasodilator, alprostadil which is known to be an effective drug in treating erectile dysfunction. ST-04 will be dispersed along the urethra, forming a hydrogel which adheres to the lining of the urethra with the goal of penile tumescence and erection. Participants may receive up to 3 dose level escalations of ST-04 over a 12-week period, for a total of up to 11 administrations of ST-04. Dose escalation may also be done with and without sildenafil.

Conditions

Erectile Dysfunction (ED); Erectile Dysfunctions; Erectile Function

Keywords

Erectile Dysfunction; Erectile Function; Alprostadil; Sildenafil

Outcome Measures

Primary Outcomes (1)

• Change from Baseline in the Erectile Function Domain of the IIEF Questionnaire

  The IIEF is a validated questionnaire assessing erectile function, with total scores ranging from 5 to 25; higher scores indicate better erectile function

  From baseline to 1 month after start of the last dose level (Week 4, 8, 12 respectively)

Secondary Outcomes (4)

• Change from Baseline in the Erectile Hardness Scale (EHS)

  From baseline to the end of treatment at week 4, 8 or 12 respectively

• Change from Baseline in the Sexual Encounter Profile (SEP)

  From baseline to the end of treatment at week 4, 8 or 12 respectively

• Percentage of Uses per Participant of ST-04 which Led to the Onset of Erection within up to 30 minutes of Application per Number of Intercourse Attempts

  From baseline to the end of treatment at week 4, 8 or 12 respectively

• Incidence and Severity of Adverse events

  From baseline to the end of treatment at week 4, 8 or 12 respectively

Study Arms (1)

Single-Arm Dose Escalation

EXPERIMENTAL

Dose Level 1 is 500 μg of ST-04; Dose Level 2 is 1000 μg of ST-04 with or without Sildenafil; Dose Level 3 is 1500 μg of ST-04 with or without Sildenafil.

Drug: ST-04

Interventions

ST-04 DRUG

ST-04 consists of an alprostadil polymer suspension designed for intraurethral application

Single-Arm Dose Escalation

Eligibility Criteria

• Age: 21 Years - 75 Years
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Have had a confirmed clinical diagnosis of ED for more than three months based upon IIEF
• Have failed PDE5 inhibitor therapy (inability to achieve an erection with adequate rigidity to allow penetrative sex)
• Ability to take oral medication (sildenafil) and be willing to adhere to the study intervention regimen
• Engaged in heterosexual relationship with partner for a minimum of 6 months

You may not qualify if:

• History of unstable medical or psychiatric condition that, in the opinion of the principal investigator, could impact the patient's ability to complete the study investigations or protocol.
• Spinal cord injury, or penile anatomical abnormalities
• Cardiovascular conditions that prevent sexual activity (NYHA Class II or higher, any angina, or uncontrolled CHF or severe coronary artery disease)
• History of myocardial infarction, stroke, or life-threatening arrhythmia within 6 months prior to enrollment into the study
• Use of anti-androgens, or oral or injectable androgens
• Documented hypotension or known orthostatic hypotension
• Use of oral, topical or sublingual nitrates within 3 months prior to enrollment into the study
• Hepatic (Child-Pugh Class C) or renal failure (eGFR \< 30)
• Inadequate response to intracavernosal injection therapy previously
• Peyronie's disease or Meatal stenosis

Sponsors & Collaborators

• Ryan Flannigan, MD: lead

Study Sites (1)

Vancouver Prostate Centre

Vancouver, British Columbia, V5Z1M9, Canada

RECRUITING

MeSH Terms

Conditions

Erectile Dysfunction

Condition Hierarchy (Ancestors)

Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Sexual Dysfunction, Physiological; Male Urogenital Diseases; Sexual Dysfunctions, Psychological; Mental Disorders

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Director of Male Reproduction & Sexual Medicine Research Program, Department of Urologic Sciences

Model Details: Single-Arm, Dose Escalation

Study Record Dates

• First Submitted: May 15, 2026
• First Posted: May 22, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): May 1, 2027
• Last Updated: May 22, 2026

Record last verified: 2026-05

Locations

CA (1)