Ibalizumab Plus Optimized Background Regimen in Patient With Multi-Drug Resistant HIV

Inclusion Criteria: * Are capable of understanding and have voluntarily signed the informed consent document * Have documented HIV-1 infection by official, signed, written history (e.g., laboratory report), otherwise an HIV-antibody test will be performed * Have no acquired immunodeficiency syndrome (AIDS)-defining events in the 3 months before Screening, other than cutaneous Kaposi's sarcoma or wasting syndrome due to HIV * Are able and willing to comply with all protocol requirements and procedures * Have a life expectancy that is \>6 months. * Have a viral load \>1,000 copies/mL and documented resistance to at least one antiretroviral medication from each of three classes of antiretroviral medications as measured by resistance testing * Have a history of at least 6 months on antiretroviral treatment * Are receiving a stable highly active antiretroviral regimen for at least 8 weeks before Screening and are willing to continue that regimen until Day 14, OR (in the past 8 weeks) have failed and are off therapy and are willing to stay off therapy until Day 14 * Have full viral sensitivity/susceptibility to at least one antiretroviral agent, other than ibalizumab, as determined by the screening resistance tests and be willing and able to be treated with at least one agent to which the patient's viral isolate is fully sensitive/susceptible according to the screening resistance tests as a component of OBR * If sexually active, are willing to use an effective method of contraception during the study and for 30 days after the last administration of the study drug Exclusion Criteria: * Any active AIDS-defining illness per Category C conditions according to the Centers for Disease Control and Prevention (CDC) Classification System for HIV Infection, with the following exceptions: cutaneous Kaposi's sarcoma and wasting syndrome due to HIV * Any significant diseases (other than HIV-1 infection) or clinically significant findings, including psychiatric and behavioral problems, determined from screening, medical history and/or physical examination that, in the investigator's opinion, would preclude the patient from participating in this study * Any significant acute illness within 1 week before the initial administration of study drug * Any active infection secondary to HIV requiring acute therapy; however, patients that require maintenance therapy (i.e., secondary prophylaxis for opportunistic infections) will be eligible for the study. * Any immunomodulating therapy (including interferon), systemic steroids, or systemic chemotherapy within 12 weeks before Enrollment * Any prior exposure to ibalizumab (formerly TNX-355 and Hu5A8) * Any vaccination within 7 days before Enrollment * Any female patient who either is pregnant, intends to become pregnant, or is currently breastfeeding * Any current alcohol or illicit drug use that, in the investigator's opinion, will interfere with the patient's ability to comply with the study schedule and protocol evaluations * Any previous clinically significant allergy or hypersensitivity to any excipient in the ibalizumab formulation * Any radiation therapy during the 28 days before first administration of investigational medication * Any Grade 3 or 4 laboratory abnormality according to the Division of AIDS grading scale, except for the following asymptomatic Grade 3 events triglyceride elevation total cholesterol elevation