Using resiniferatoxin to relieve pain from Morton's neuroma

Phase I Open Label Clinical Trial Using Resiniferatoxin, A Non-Opioid Medication, For the Management of Refractory Morton's Neuroma Pain

Phase 1 Interventional National Institutes of Health Clinical Center (CC) · NCT05695339

This study is testing if a new injection called resiniferatoxin can help relieve pain for people suffering from Morton's neuroma.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment24 (estimated)
Ages18 Years and up
SexAll
SponsorNational Institutes of Health Clinical Center (CC) NIH
Locations1 site (Bethesda, Maryland)
Trial IDNCT05695339 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to evaluate the safety and effectiveness of resiniferatoxin (RTX) for managing pain associated with Morton's neuroma. Participants will receive a single ultrasound-guided perineural injection of RTX and will be monitored for up to four months. The study will assess pain intensity, daily function interference, and any adverse effects related to the treatment. The goal is to provide a long-lasting solution for patients who have not found relief from standard treatments.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with a diagnosis of Morton's neuroma who have not achieved satisfactory pain relief from previous treatments.

Not a fit: Patients who have not been diagnosed with Morton's neuroma or those who have not tried standard treatments may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could offer long-term pain relief for patients suffering from Morton's neuroma.

How similar studies have performed: While the use of resiniferatoxin is a novel approach, similar studies targeting neuropathic pain have shown promising results.

Eligibility criteria

Show full inclusion / exclusion criteria
* INCLUSION CRITERIA:

Both male and female participants are eligible for study evaluation. There are no exclusions for any racial/ethnic groups. Efforts will be made to extend accrual to a representative population. In order to be eligible to participate in this study, an individual must meet all of the following criteria:

* Provision of signed and dated informed consent form.
* Ability of subject to understand and the willingness to sign a written informed consent document.
* Must be able to read, write, understand, and complete English-language study-related forms and adequately communicate in English.
* Stated willingness to comply with all study procedures and availability for the duration of the study.
* Male or female, aged 18 and older.
* In good general health as evidenced by medical history.
* Diagnosed with one painful Morton s neuroma in the index foot
* Has not attained satisfactory pain relief with conservative, oral analgesic and at least one kind of injection treatment for Morton s neuroma.
* Exhibits moderate to severe foot pain due to the Morton s neuroma (average worst pain \>= 5 on the 0-10 numeric pain rating scale NRS) as assessed verbally at \>= 3 individual days during prescreening.
* For females of reproductive potential who are sexually active: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation and for an additional one (1) month after administration of RTX.

If a female, be sterile (surgically or biologically) \* or at least one year postmenopausal\*\*, or have a monogamous partner who is surgically sterile, or have a same sex partner, or if in a heterosexual relationship, must agree to do the following for at least one month after receiving investigational product (IP):

* Practice abstinence, or
* Use at least one of the following medically acceptable methods of birth control:

  * Hormonal methods such as oral, implantable, injectable, vaginal ring, or transdermal contraceptives (must have started a minimum of 1 full cycle, based on the subject s usual menstrual cycle period, before IP dose
  * Intrauterine device
  * Double-barrier method (condoms, sponge, or diaphragm with spermicidal jellies or cream).

    * Defined as having had a hysterectomy and/or bilateral oophorectomy, bilateral salpingectomy or bilateral tubal ligation/occlusion at least 6 weeks prior to screening; or having a congenital or acquired condition that prevents childbearing

      * Defined as at least 12 months with no menses without an alternative medical cause) \[can be confirmed with follicle stimulating hormone level (FSH) in the post-menopausal range (FSH levels \>=40 milli international units/mL (mIU/mL) at Screening) if the subject is not on hormonal replacement therapy\]
* For males of reproductive potential who are sexually active: use of condoms or other methods to ensure effective contraception with partner for one (1) month after administration of (RTX).

If a male of reproductive potential, unless he has a same sex partner or a partner who is sterile or at least one year post-menopausal, must agree to do the following for at least one month after receiving IP

* practice abstinence from heterosexual activity or
* use (or have their partner use) acceptable contraception (see criterion above) during heterosexual activity

Male study participants should not donate sperm for 3 months after RTX injection.

EXCLUSION CRITERIA:

An individual who meets any of the following criteria will be excluded from participation in this study:

* Pregnancy or lactation.
* Has a known allergy or hypersensitivity to chili peppers or capsaicin.
* Has a known allergy to local anesthetics.
* Has active or history of rheumatoid arthritis or peripheral neuropathy.
* Has a prolonged baseline QTc interval exceeding 480 milliseconds.
* Current presentation of other currently painful pathology of the same foot affected by Morton s neuroma, including, but not limited to, hallux valgus, plantar fasciitis, hammer toes, metatarsalgia, bursitis.
* History of injection and/or ablation treatments treatment in the affected foot up to one month previous to study participation.
* History of nerve excision due to Morton s neuroma in the location to be treated with RTX.
* Active cutaneous disease, inflammation or infection at the anticipated site of study drug injection.
* Has diabetes mellitus or peripheral vascular disease whether poorly managed or stable.
* Has more than one Morton s neuroma in the index foot scheduled to receive the treatment intervention.
* Other clinically significant condition that might interfere with study participation or greatly increases safety risk to the subject, as judged by the study investigator.
* Concurrent treatment with another investigational drug or other intervention within last month.
* Cognitive or language difficulties that would impair comprehension or completion of the assessment instruments.

Where this trial is running

Bethesda, Maryland

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Morton's NeuromaNeuropathicForefootUltra-Sound GuidedCommon Plantar Digital NervePerineural InjectionTrpv1Morton's Disease
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.