SON-080 in Patients With Persistent Chemotherapy-induced Peripheral Neuropathy (CIPN)

Inclusion Criteria: * Age ≥18 years, inclusive, at the time of Screening. * Have persistent CIPN at 3 months or more after chemotherapeutic treatment arrest (QLQ-CIPN20 score of 30 to 100). * Have a history of cancer that is stable or in remission at the time of study entry. * Have a history of treatment with a chemotherapeutic agent in the taxane, organoplatin, or vinca alkaloid family. * Must have an Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1 at Screening. * Must have adequate organ function, defined as: * Hematologic function defined as National Cancer Institute (NCI) CTCAE Grade 1 or less for all blood parameters. * Renal function defined as calculated creatinine clearance or radioisotope glomerular filtration rate \>60 mL/min/1.73 m2 or normal serum creatinine with a maximum serum creatinine of 1.7 mg/dL for males and 1.4 mg/dL for females. * Hepatic Function defined as: * Alanine aminotransferase (ALT) ≤3 × the upper limit of normal (ULN) for age. * Total bilirubin ≤1.5 × ULN (unless the patient has Grade 1 bilirubin elevation due to Gilbert's disease or a similar syndrome involving slow conjugation of bilirubin). * Either the patient or the caregiver must be willing and able to administer SC treatment in an at-home setting after training. * Female patients of childbearing potential who are not currently pregnant or lactating must have a negative serum pregnancy test (beta-human chorionic gonadotropin \[β HCG\]) on day 1 and agree to abstinence or use a highly effective method of birth control for 30 days before the study, during the study, and for 30 days after the last dose of study intervention. Females who are not of childbearing potential (have had a tubal ligation, hysterectomy, or bilateral oophorectomy, or are ≥ 1-year postmenopause) or have a partner who has had a vasectomy do not need to use any contraception. * Nonchildbearing potential is defined as surgically sterile (documented hysterectomy, tubal ligation, or bilateral salpingo-oophorectomy) or postmenopausal (defined as 12 months of spontaneous amenorrhea). If necessary, a follicle-stimulating hormone (FSH) level ≥ 35 IU/L at Screening will be considered confirmatory in the absence of a clear postmenopausal history. If a patient is not sexually active, but becomes active, then she and her male partner must use adequate contraception. * Male patients and their female partners must agree to use adequate contraception (including a barrier method) during the study and for 30 days after the last dose of SON-080. Contraception guidance is described in the protocol. * If a patient is not sexually active, but becomes active, then he and his female partner must use adequate contraception. Male patients must refrain from sperm donation for 90 days after the last dose of SON-080. * Must be willing and able to provide voluntary written informed consent to participate in the study. * Must be able to communicate well with the Investigator and/or study site personnel and to comply with the requirements of the entire study. Exclusion Criteria: * Evidence of current alcohol or drug dependence. * Evidence for other cause of chemotherapeutic neuropathy, e.g., use of colchicine, amiodarone, thalidomide, vitamin B12 deficiency, etc. * Unresolved toxicities from prior anticancer therapy, defined as not having resolved to baseline or to CTCAE Grade 1, except for alopecia, or to the levels dictated in the inclusion/exclusion criteria. * Active infection with SARS-CoV-2, as determined by local SOPs for testing during Screening. * History of hepatic disease or active clinically significant liver function test results, defined as chronically abnormal ALT, aspartate aminotransferase (AST), total bilirubin and fractionated bilirubin, and alkaline phosphatase \>1.5 × the ULN. Note: Isolated bilirubin \>1.5 × ULN is acceptable if bilirubin is fractionated and direct bilirubin is \<35%. * Diagnosis of or positive screening result for hepatitis B surface antigen (HbsAg), hepatitis C virus antibody (HCVAb), or human immunodeficiency virus (HIV)-1 or HIV-2. * Known allergies to any of the ingredients of the medicinal product or to acetaminophen. * History of brain metastases. * Diagnosed with lymphoma, Kaposi's sarcoma, or multiple myeloma. * Significant unstable vascular disease, as judged by the Investigator. * Any other investigational drug in the 4 weeks preceding treatment administration. Note: COVID-19 vaccines will be allowed if administered more than 14 days before the first dose administration. * Clinical history of a thrombosis, deep vein thrombosis, or pulmonary embolus in the past year. * Other serious concurrent medical condition which, in the opinion of the Investigator, would preclude inclusion in the study. * History of any active infection within 14 days before the first dose of SON-080, if deemed clinically significant by the Investigator and Sponsor. * Concurrent conditions that could interfere with safety and/or tolerability measurements. * Pregnant and/or lactating. * Unable or unwilling to cooperate with the Investigator for any reason.