Study of Antibody for Methamphetamine Outpatient Therapy

Inclusion Criteria: * Subject voluntarily agrees to participate in this study and signs an informed consent form. * Subject must be able to verbalize understanding of the consent forms, provide written informed consent, and verbalize willingness to complete study procedures. * Males or females between 21 to 50 years of age, inclusive. Female subjects should be of non-childbearing potential or, they should be nonpregnant, nonlactating, and agree to use medically acceptable forms of birth control from screening to end-of-study follow-up, or have a partner who has had a vasectomy. Male subjects need to have had a vasectomy or agree to use a condom and spermicide in addition to their female partners using a form of birth control. They should agree not to donate sperm for 90 days post IXT-m200 dose. * Body mass index (BMI) between 18.0 and 35.0 kg/m2. Body weight ≥ 50 kg and ≤ 100 kg. * Subjects have hematology and chemistry laboratory tests that are within normal (+/- 10%) limits with the following exceptions: a) liver function tests (total bilirubin, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase) \< 3 times the upper limit of normal, and b) kidney function tests (creatinine and BUN) \< 2 times the upper limit of normal. * Subjects meet Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 criteria for METH use disorder and are not seeking treatment at the time of the study. * Subjects will be experienced METH users with a history of non-therapeutic METH use for 2 or more years. Subjects must have experience with smoking or IV injection of METH. * Current METH use (past 30 days) less than daily, self-reported and documented by calendar-based timeline follow-back. * Primary current (past 30 days) route of METH self-administration other than IV (ie, smoking, snorting, or oral). * Subjects agree not to take METH from any source outside of the study during their participation in the study. Subjects agree not to take substances that are structurally similar to METH. * Subjects must provide a negative urine sample prior to admission to the unit on Day -1 for the study. Exclusion Criteria: * Subjects who have been treated with a monoclonal antibody (mAb) in the past year. * Known or suspected allergy sensitivity to IXT-m200 based on known allergies to other mAbs. * History of severe allergy (rash, hives, breathing difficulty, etc) to any medications. * History of allergic or environmental bronchial asthma. * Clinically significant history of or current abnormality or disease of any organ system, including renal, hepatic, GI, cardiovascular, pulmonary (including chronic asthma), endocrine (eg, diabetes), central nervous, or hematologic systems, or recent clinically significant surgery. * Current diagnosis or history of major psychiatric illness in the past two years or other current psychiatric condition requiring medication, other than methamphetamine dependence. * Considered by the PI to be at imminent risk of suicide or injury to self, others, or property, or the subject has attempted suicide with the past year. Past year history of, or current evidence for, suicidal ideation or those who were actively suicidal based on the Columbia-Suicide Severity Rating Scale (C-SSRS). * Current dependence on alcohol or heavy use defined as \>28 alcoholic drinks per week if male and \>21 drinks per week if female in last 30 days. * Current dependence on other drugs except amphetamines, or marijuana and nicotine used in moderate amounts. * History of seizure, epilepsy, severe head injury with residual neurologic effects, multiple sclerosis, or stroke. * Abnormal pre-admission vital signs, physical examination, clinical laboratory, ECG, or any safety variable which is considered clinically significant for this population. * History of cardiovascular disease. * Treatment with any prescription medications or over the counter nutritional supplements within 14 days prior to the first dose of study medication. * Ingestion of any approved prescription anti-obesity drug or taken any over-the-counter medication for weight loss within a period of 90 days prior to the first dose of study medication. * Ingestion or use of any investigational medication or device within 30 days prior to the first dose of study medication. * Acute illness within 5 days prior to the first dose of study medication, eg, flu syndrome, GI virus, or clinically significant indigestion (eg, reflux). * Positive result for hepatitis B surface antigen (HBsAG), hepatitis C (HepC) antibody, hepatitis A immunoglobulin M (IgM), or HIV Viral Serology, or nucleic acid testing (NAT) tests at screening. * Positive breath alcohol test or positive urine drug test for illicit substances on Day -1. * Subjects with history of donated blood, plasma, or platelets in last 30 days, and who do not agree to refrain from blood, plasma, platelets, egg or sperm donation during the study period. * Predominant or only route of METH self-administration is IV. * Any subject judged by the PI or Sponsor (or designee) to be inappropriate for the study.