A Phase 2 interventional study of IncobotulinumtoxinA (100 Units) and Placebo in Erectile Dysfunction, sponsored by Northwestern University. Not yet recruiting. Open to male participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-08-14.
Sponsored by Northwestern University · Phase 2, Interventional, and Treatment
Erectile dysfunction (ED) affects approximately 30 million men in the United States and is associated with factors such as aging, smoking, diabetes, hypertension, obesity, and sedentary lifestyle. ED can also negatively impact the quality of life of patients and their partners. Treatment decisions are typically made jointly between patients and their urologists, often starting with less invasive options. Oral phosphodiesterase-5 inhibitors (PDE5 inhibitors), including sildenafil, tadalafil, and vardenafil, are commonly used as first-line therapy. While these medications improve erectile function in many patients, approximately 30-40% do not respond adequately to PDE5 inhibitor therapy alone. Patients who do not achieve sufficient benefit may require additional or more invasive treatment options.
701 studies on the registry are indexed under Erectile Dysfunction; 125 are open to participants now.
This study's planned enrollment of 30 is below the median of 70 across 551 interventional studies indexed under Erectile Dysfunction.
Browse Erectile Dysfunction studies →Northwestern University is the lead sponsor of 1,423 studies on the registry; 198 are open to participants now.
Of its 105 completed or terminated interventional studies of FDA-regulated products, 78 (74%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Subjects in this portion of the trial will be administered 20 mg of Tadalafil in conjunction with 100 units of Xeomin
Drug: IncobotulinumtoxinA (100 Units) · Drug: Tadalafil 20 MG
Subjects in this portion of the trial will be administered 20 mg of Tadalafil in conjunction with a placebo
Other: Placebo · Drug: Tadalafil 20 MG
Intracavernosal Xeomin
Placebo
PDE5 Inhibitor Medication
Change in erectile function
Change in erectile function as measured by the validated IIEF-EF domain (3-6 months) following Xeomin portion of the crossover study. This domain provides a score on a scale of 6-30, where scores can be interpreted as follows: * 26-30: No Erectile Dysfunction * 22-25: Mild Erectile Dysfunction * 17-21: Mild to Moderate Erectile Dysfunction * 11-16: Moderate Erectile Dysfunction * 6-10: Severe Erectile Dysfunction
Time frame: 3-6 months
Change in erectile hardness
Change in erectile hardness as measured by the validated erectile hardness scale (EHS) (3-6 months) following Xeomin portion of the crossover study. The scale ranges from Grade 0 - Grade 4. It measures the firmness of an erection using the following grade interpretation: * Grade 0: Penis does not enlarge. * Grade 1: Penis is larger, but not hard. * Grade 2: Penis is hard, but not hard enough for penetration. * Grade 3: Penis is hard enough for penetration, but not completely hard. * Grade 4: Penis is completely hard and fully rigid
Time frame: 3-6 months
Persistence of efficacy in erectile function
Persistence of efficacy in erectile function as measured by the validated IIEF-EF domain (3-6 months in placebo portion of crossover study). This domain provides a score on a scale of 6-30 over a period of time, where scores can be interpreted as follows: * 26-30: No Erectile Dysfunction * 22-25: Mild Erectile Dysfunction * 17-21: Mild to Moderate Erectile Dysfunction * 11-16: Moderate Erectile Dysfunction * 6-10: Severe Erectile Dysfunction
Time frame: 3-6 months
Persistence of efficacy in erectile hardness
Persistence of efficacy in erectile hardness as measured by the validated erectile hardness scale (EHS) (3-6 months in placebo portion of crossover study). The scale ranges from Grade 0 - Grade 4. It measures the firmness of an erection over a period of time using the following grade interpretation: * Grade 0: Penis does not enlarge. * Grade 1: Penis is larger, but not hard. * Grade 2: Penis is hard, but not hard enough for penetration. * Grade 3: Penis is hard enough for penetration, but not completely hard. * Grade 4: Penis is completely hard and fully rigid
Time frame: 3-6 months
No study locations are listed for this record.
Plan to share: No
Start is estimated for Sep 2026; primary completion for Sep 2028, 24 months later.
Of 24 phase 2 interventional studies under Erectile Dysfunction, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 16 and three quarters within 32. This study's planned 24 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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