Neoadjuvant Intraprostatic OnabotulinumtoxinA Before Radical Prostatectomy for High-Risk Localized Prostate Cancer

August 31, 2026 updated by: Brian Miles, The Methodist Hospital Research Institute

A Pilot Randomized, Single Blind, Placebo Controlled Study of Neoadjuvant Intraprostatic OnabotulinumtoxinA Prior to Radical Prostatectomy in Patients With High Risk Localized Prostate Cancer

This pilot randomized, single-blind, placebo-controlled study evaluates the feasibility, safety, and preliminary biological activity of neoadjuvant intraprostatic onabotulinumtoxinA (BOTOX®) administered before radical prostatectomy in men with high-risk localized prostate cancer. Thirty participants will be randomized 1:1 to receive a single transrectal ultrasound-guided intraprostatic injection of onabotulinumtoxinA (50 units) or placebo 6 to 8 weeks before surgery. Outcomes include feasibility metrics, safety, adverse events, pathological findings at prostatectomy, and postoperative prostate-specific antigen (PSA) levels

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

High-risk localized prostate cancer is associated with a substantial risk of adverse pathological features and disease recurrence despite definitive treatment with radical prostatectomy. Emerging evidence suggests that neural signaling within the prostate tumor microenvironment contributes to tumor growth, progression, and treatment resistance. OnabotulinumtoxinA (BOTOX®), a neurotoxin that blocks acetylcholine release, has demonstrated biological effects in prostate tissue and may provide a novel approach to modulating tumor-associated neural pathways.

This single-center, prospective, randomized, single-blind, placebo-controlled pilot study will enroll 30 men with high-risk or very-high-risk localized prostate adenocarcinoma who are scheduled to undergo radical prostatectomy. Participants will be randomized in a 1:1 ratio to receive either a single transrectal ultrasound-guided intraprostatic injection of onabotulinumtoxinA (50 units) or an equivalent-volume normal saline placebo 6 to 8 weeks prior to surgery. Participants will remain blinded to treatment assignment.

The primary objective is to evaluate study feasibility and safety, including participant accrual, protocol adherence, successful completion of intraprostatic injection and planned surgery, and the incidence and severity of adverse events. Secondary objectives include evaluation of pathological outcomes at prostatectomy, including Gleason score, perineural invasion, stromogenic component, tumor burden, pathological stage, and surgical margin status. Early postoperative PSA outcomes will also be assessed. Exploratory analyses will evaluate time to biochemical recurrence following radical prostatectomy.

This pilot study is not powered to demonstrate clinical efficacy. Instead, it is designed to establish the safety and feasibility of neoadjuvant intraprostatic onabotulinumtoxinA and generate preliminary biological and pathological data to support future studies investigating neural modulation as a therapeutic strategy in prostate cancer.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Texas
      • Houston, Texas, United States, 77030
        • Houston Methodist

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male, ≥ 45 years
  • Histologically confirmed prostate adenocarcinoma
  • Gleason score ≥8 on biopsy
  • Candidate for and scheduled to undergo RALP for primary treatment
  • ECOG 0-2
  • Able to read, speak, and understand English
  • Able to provide informed consent

Exclusion Criteria:

  • Prior prostate cancer therapy (radiation, ADT, chemotherapy)
  • Metastatic disease
  • Known hypersensitivity to botulinum toxin
  • Neuromuscular disorders (e.g., myasthenia gravis)
  • Active infection, coagulopathy, or contraindication to transperineal injection
  • Medications significantly affecting neuromuscular transmission (clinically relevant)
  • Any condition compromising safety or protocol compliance

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Botox
A single transperineal, transrectal ultrasound (TRUS)-guided intraprostatic injection of onabotulinumtoxinA, total dose 50 units, administered 6 to 8 weeks prior to radical prostatectomy.
Drug: OnabotulinumtoxinA (BOTOX®)
A single transperineal, transrectal ultrasound (TRUS)-guided intraprostatic injection of onabotulinumtoxinA, total dose 50 units, administered 6 to 8 weeks prior to radical prostatectomy.
Other Names:
  • Botox
Placebo Comparator: Placebo
A single transperineal, transrectal ultrasound (TRUS)-guided intraprostatic injection of normal saline placebo administered in an identical volume and injection pattern 6 to 8 weeks prior to radical prostatectomy.
Other: Normal Saline Placebo
Participants randomized to the placebo arm will receive a single transperineal, transrectal ultrasound (TRUS)-guided intraprostatic injection of normal saline administered in an identical volume and injection pattern as the active treatment arm, 6 to 8 weeks prior to planned radical prostatectomy.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Participant Accrural
Time Frame: Through study completion, an average of 1 year
Number of participants enrolled in the study
Through study completion, an average of 1 year
Protocol Adherence
Time Frame: Through study completion, an average of 1 year
Proportion of participants who complete study procedures according to protocol requirements.
Through study completion, an average of 1 year
Successful Completion of Intraprostatic Injection
Time Frame: At time of surgery
Number of participants who successfully receive the assigned intraprostatic study injection.
At time of surgery
Incidence of Adverse Events
Time Frame: From study injection through 36 months of follow-up.
Incidence, severity, seriousness, and relationship of adverse events associated with intraprostatic administration of onabotulinumtoxinA or placebo.
From study injection through 36 months of follow-up.
Successful Completion of Planned Radical Prostatectomy
Time Frame: Within 6 to 8 weeks after intraprostatic injection.
Proportion of participants who undergo planned radical prostatectomy following study intervention without study-related cancellation or unacceptable delay.
Within 6 to 8 weeks after intraprostatic injection.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Gleason Score at Radical Prostatectomy
Time Frame: At radical prostatectomy (6 to 8 weeks after study injection).

Comparison of Gleason score determined from radical prostatectomy specimens between treatment arms.

Gleason Score determined from radical prostatectomy specimens. Gleason Scores range from 6 to 10, with higher scores indicating more aggressive prostate cancer.
At radical prostatectomy (6 to 8 weeks after study injection).
Perineural Invasion
Time Frame: At radical prostatectomy (6 to 8 weeks after study injection).
Presence and extent of perineural invasion identified in radical prostatectomy specimens.
At radical prostatectomy (6 to 8 weeks after study injection).
Stromogenic Component
Time Frame: At radical prostatectomy (6 to 8 weeks after study injection).
Assessment of stromogenic component in radical prostatectomy specimens.
At radical prostatectomy (6 to 8 weeks after study injection).
Tumor Size
Time Frame: At radical prostatectomy (6 to 8 weeks after study injection).
Tumor size measured in radical prostatectomy specimens. The measurement will be recorded in centimeters (cm).
At radical prostatectomy (6 to 8 weeks after study injection).
Positive Surgical Margin Status
Time Frame: At radical prostatectomy (6 to 8 weeks after study injection).
Proportion of participants with positive surgical margins following radical prostatectomy.
At radical prostatectomy (6 to 8 weeks after study injection).
Postoperative Prostate-Specific Antigen (PSA)
Time Frame: 6 to 8 weeks after radical prostatectomy and during follow-up through 36 months.
Serum PSA levels following radical prostatectomy.
6 to 8 weeks after radical prostatectomy and during follow-up through 36 months.

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Time to Biochemical Recurrence
Time Frame: Up to 36 months after radical prostatectomy.
Time from radical prostatectomy to biochemical recurrence as defined by postoperative PSA progression.
Up to 36 months after radical prostatectomy.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
The Methodist Hospital Research Institute

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Brian Miles, MD, Houston Methodist Urology, Houston Methodist Research Institute

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 20, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 27, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 1, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 31, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • Pro00046310

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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