Inclusion Criteria:  Able to comprehend and willing to sign an informed consent form (ICF) and to abide by the study restrictions. Adult females and males, of any race, between 18 and 55 years of age, inclusive, at Screening.  Females of non-childbearing potential, which is defined as permanently sterile (ie, due to hysterectomy, bilateral salpingectomy, or bilateral oophorectomy), or with bilateral tubal ligation or Essure® (hysteroscopic bilateral tubal occlusion) with confirmation of occlusion of the fallopian tubes performed at least 3 months prior to Screening, or postmenopausal (defined as at least 12 months post cessation of menses without an alternative medical cause and follicle-stimulating hormone [FSH] level  ≥ 40 mIU/mL). Males will agree to use contraception and refrain from sperm donation.  Body mass index between 30.0 and 39.9 kg/m^2, inclusive, at Screening. Glycosylated hemoglobin (HbA1c) level of < 6.5% at Screening (test may be repeated once for confirmation of out-of-range values).  Vital signs at Screening and Check-in as per the following ranges and stable (measured in a supine position after a minimum of 5 minutes of rest):  Systolic blood pressure ≥ 90 and ≤ 140 mmHg Diastolic blood pressure ≥ 50 and ≤ 90 mmHg Pulse rate ≥ 50 and ≤ 100 bpm In good health, determined by no clinically significant findings from medical history, physical examination, 12-lead ECG, vital sign measurements, and clinical laboratory evaluations at Screening and/or Check-in as assessed by the Investigator (or designee).  Exclusion Criteria:  Any clinically important illness, medical/surgical procedure, or trauma within 4 weeks prior to dose administration on Day 1. Significant history or clinical manifestation of any metabolic, allergic, dermatological, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, neurological, respiratory, endocrine, or psychiatric disorder, as determined by the Investigator (or designee). Obesity induced by known endocrine or genetic disorders (eg, Cushing syndrome, hypothyroidism, Prader Willi syndrome). Any previous surgical treatment or procedures with medical devices (such as insertion of lap band or gastric balloons) for obesity (excluding liposuction if performed > 1 year prior to Check-in). History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance, which would increase the subject's risk of participation. History of stomach or intestinal surgery or resection that would potentially alter absorption and/or excretion of orally administered drugs (uncomplicated appendectomy, cholecystectomy, and hernia repair > 6 months prior to Screening will be allowed). History or evidence of underlying liver disease, including viral (hepatitis B and C) or alcoholic hepatitis, or confirmed diagnosis of nonalcoholic steatohepatitis (NASH); nonalcoholic fatty liver disease (NAFLD) with qualifying liver function tests (LFTs) will be allowed. Gilbert's Syndrome (congenital non-hemolytic hyperbilirubinemia) or suspicion of Gilbert's Syndrome based on total and direct bilirubin.  Laboratory results that exceed the following thresholds at Screening AND Check-in (laboratory tests may be repeated once for confirmation of out-of-range values) as specified:  alanine aminotransferase (ALT) > 1.5 × upper limit of normal (ULN) aspartate aminotransferase (AST) > 1.5 × ULN gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), total bilirubin, or International Normalized Ratio (INR) > ULN Hemoglobinopathy, hemolytic anemia, or chronic anemia (hemoglobin concentration < 13.0 g/dL [130 g/L] for males, < 11.0 g/dL [110 g/L] for females) at Screening or any other condition known to interfere with interpretation of HbA1c measurement Neutrophils < 1.5 × 109/L deemed clinically significant by Investigator upon a confirmatory repeat Thyroid-stimulating hormone (TSH) level above the normal range, confirmed on repeat History or presence of cardiac arrhythmia (at the discretion of the Investigator) or congenital long QT syndrome. A QT interval corrected for heart rate using Fridericia's method (QTcF) > 450 msec for males or > 470 msec for females on Screening ECG. At the discretion of the Investigator, ECG may be repeated twice and an average taken of the 3 readings. The subject has creatinine clearance ≤ 80 mL/minute as calculated using the Cockroft-Gault equation. At the discretion of the Investigator, evaluation may be repeated once to confirm. History of alcoholism or drug/chemical abuse within 2 years prior to Check in. Alcohol consumption of > 14 units per week. One unit of alcohol equals 12 oz (360 mL) of beer, 1½ oz (45 mL) of liquor, or 5 oz (150 mL) of wine. Positive urine drug screen at Screening; or positive alcohol breath test result or positive urine drug screen at Check-in. Positive hepatitis B surface antigen and/or hepatitis C antibody and/or positive human immunodeficiency virus 1/2 (Appendix 2). Participation in a clinical study involving administration of an investigational drug (new chemical entity) in the past 30 days or 5 half-lives prior to dosing, whichever is longer. Subjects who are actively dieting, have gained or lost > 5 pounds, or using or intend to use any prescription or nonprescription drugs for weight loss including herbal or other dietary supplements within 3 months prior to Check-in. Use or intend to use any medications/products known to alter drug absorption, metabolism, or elimination processes, including St. John's wort, within 30 days prior to Check-in and throughout the outpatient Follow-up period. Use or intend to use any prescription medications/products within 30 days prior to Check-in, unless deemed acceptable by the Investigator (or designee). Use or intend to use slow-release medications/products considered to still be active within 14 days prior to Check-in, unless deemed acceptable by the Investigator (or designee). Use or intend to use any nonprescription medications/products including vitamins, minerals, and phytotherapeutic/herbal/plant-derived preparations within 14 days prior to Check-in and throughout the outpatient Follow-up period, unless deemed acceptable by the Investigator (or designee). Consumption of alcohol from 72 hours prior to Check-in. Use of tobacco- or nicotine-containing products (including nicotine and non-nicotine e-cigarettes, vaping, etc.) within 3 months prior to Check-in, or positive cotinine at Screening or Check-in. Receipt of blood products within 2 months prior to Check-in. Donation of blood from 8 weeks prior to Screening, plasma from 2 weeks prior to Screening, or platelets from 6 weeks prior to Screening. Poor peripheral venous access. Have previously completed or withdrawn from this study or any other study investigating ERX1000, and have previously received the investigational product. Subjects who, in the opinion of the Investigator (or designee), should not participate in this study.