This research is being done to study a possible treatment for refractory pain due to small fiber neuropathy (SFN).
ST-503 is intended to deliver a modified copy of the gene which will ideally repress Nav1.7 tissue-related pain signals reaching the brain, which should reduce the refractory pain due to small fiber neuropathy (SFN).
Diagnostic characterization of Small Fiber Neuropathy (SFN) according to the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities and Networks (ACTTION) criteria.
Medical record documentation that pain is refractory to 2 of 3 categories of first line medical therapy for at ≥ 6 months prior to screening.
Serum sample negative for pre-existing anti-AAV9 antibodies determined by assay detection limit
Persons using opioid analgesics for under 3 months or persons who are not on a stable dose of opioids; if on a stable dose, the dose may decrease over the course of the study but should not be increased.
History of known alcohol abuse, opioid analgesic abuse, or illicit drug abuse within 2 years of Screening.
Positive urine test for drugs of abuse (including opiates, benzodiazepines, amphetamines, cocaine, barbiturates, and phencyclidine) without prescription and investigator approval, at Screening and Day -1.
Use of cannabinoids is not permitted.