Subjects who have completed study 4975-MN-202 will be eligible to receive open-label treatment with CNTX-4975 200 µg in study 4975-MN-203 if they meet the inclusion/exclusion criteria.

Inclusion Criteria:

1. Male or female aged >18 years at the time of the Screening Visit.

2. Completion of study 4975-MN-202.

3. Female not of childbearing potential, defined as post-menopausal for at least 1 year, or surgically sterile (bilateral tubal ligation, bilateral oophorectomy, or hysterectomy), or practicing one of the following medically acceptable methods of birth control throughout the study period:

   1. Hormonal methods such as oral, implantable, injectable, or transdermal contraceptives for a minimum of 1 full cycle (based on the subject's usual menstrual cycle period) before investigational product (IP) administration.
   2. Total abstinence from sexual intercourse since the last menses before IP administration.
   3. Intrauterine device.
   4. Double barrier method (condoms, sponge, diaphragm, with spermicidal jellies or cream).

4. Willing and able to understand the study requirements, abide by the study restrictions, complete the study procedures, pain scales, and weekly IWRS/IVRS entries, and to communicate meaningfully with the study personnel.

5. Signed an Informed Consent Form approved by the Institutional Review Board.

6. Subject agrees to take only the rescue medications for neuroma foot pain from the time of screening through study completion, and agrees to discontinue all topical medications for neuroma pain after Screening.

Exclusion Criteria:

1. Other chronic pain anywhere in the body that is severe in intensity or would interfere with the subject's ability to evaluate foot pain from intermetatarsal neuroma.
2. Signs of arterial insufficiency in the feet, including clinically meaningful edema.
3. Raynaud's disease or phenomenon, previous frostbite, or other cause of vascular instability in the feet resulting from application of cold to the foot.
4. Daily use of opioids for any condition.
5. Corticosteroid injection in the affected foot within 30 days of Screening.
6. Presence of any medical condition (or taking any medication) or unstable health status that, in the judgment of the investigator, might adversely impact the conduct of the study or resulting data, including chronic conditions that are likely to alter the rate of healing or are likely to result in safety complications unrelated to the study medication, such as uncontrolled diabetes mellitus or vascular disease.
7. Clinically significant abnormal laboratory result at the Screening Visit (in the opinion of the investigator).
8. Has a positive pregnancy test at the Screening Visit.