Resiniferatoxin for the Management of Refractory Morton s Neuroma Pain

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