A Randomized, Controlled Study of Repeat Dose Sustained Release Lidocaine for Treatment of Chronic Scrotal Pain

This multi-center, phase 2, randomized, single-blind, three-arm, active-controlled study is comparing repeat doses, every 28 days, of standard of care (SOC) plus ST-01 against SOC plus 1% lidocaine HCL in men experiencing chronic scrotal content pain (CSCP). The main purpose of this study is to determine if repeat injections of ST-01 are safe and effective in reducing pain. After completing a screening phase participants will be randomized into one of three groups: 1) ST-01 70 mg/mL arm, 2) ST-01 140 mg/mL arm, 3) 1% Lidocaine HCL arm (Control). Participants may receive up to 4 study treatment injections given at a minimum of 28-day intervals. Participants randomized to the Control arm will be given the opportunity to cross over to an ST-01 treatment arm after 2 study treatments.

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Key information

Conditions

Chronic Pain Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

19 year and older

Sex eligibility

Male

Study type

Interventional

Phase

Phase 2

Primary location

Prostate Cancer Centre - Rockyview Hospital, Calgary, Alberta, Canada

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Adult (≥ 19 years) male
Unilateral or bilateral scrotal pain lasting > 3 months
Have nociceptive scrotal pain
Average daily maximum scrotal pain score over 7 days ≥ 4 on the 0-10 NRS (Appendix 2). Participants with bilateral scrotal pain must be able to distinguish one side with pain score ≥ 4 and the opposite side must have a maximum scrotal pain score of ≤ 3.0 at baseline.
Positive response to test spermatic cord block with 1% lidocaine (Lidocaine Hydrochloride Injection, USP, 1%, 10 mg/mL), defined as a decrease in pain score of at least 2 within 1 hour of injection
Baseline blood levels without clinically significant abnormalities including liver function tests (alanine aminotransferase [ALT], aspartate aminotransferase [AST], gamma-glutamyl transferase [GGT], and alkaline phosphatase [ALP]) no greater than 50% above the upper limit of normal
If sexually active, is willing to use adequate birth control methods to prevent pregnancy over the course of the study

Exclusion criteria

Negative response to test spermatic cord block, defined as absence of a decrease in pain score of at least 2 within an hour of injection
Other pain generator site with NRS pain score ≥ 4 that interferes with evaluation of scrotal pain
History of allergic reaction to lidocaine or any component of ST-01
Any contraindication to local anesthesia with lidocaine (e.g., known hypersensitivity to anesthetics of the amide type; hypokalemia, complete heart block, anticoagulants (aspirin permitted), antiarrhythmic medication.)
Active infection involving the urinary tract or scrotum
Inability to give consent
Inability to follow up according to the protocol
Negative response to previous spermatic cord block
Any other condition that the investigator believes may interfere with the safety of the participant, study conduct, or interpretation of the data.

Treatment and study plan

ST-01

Drug

A sustained release lidocaine formulation designed for the treatment of acute and chronic pain.

1% Lidocaine HCL

Drug

Currently approved lidocaine

Primary outcomes

Change From Baseline in Pain Scores on the Numerical Rating Scale (NRS) at 56 days.

Time frame: 28 days after the second injection of ST-01 or 56 days after the first injection if only one study injection is received.

To evaluate the change of pain score from baseline to day 56 in the active treatment cohorts (after 1 or 2 injections of ST-01) and compare to the standard of care control group. Pain score being used is the participant reported NRS scale (measured from 0-10 where 0 is no pain and 10 is maximum pain.)

Sponsors and collaborators

Lead sponsor

Sustained Therapeutics Inc.

Industry

Registry information

Official study title

A Randomized, Controlled Phase II Study of Repeat Dose ST-01 (Lidocaine Polymer Solution) vs Lidocaine for Spermatic Cord Block in Men With Chronic Scrotal Content Pain

Important dates

Study start: 2023
Primary completion: 2025
Study completion: 2026
First posted: Jan 31, 2023
Registry last updated: Mar 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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