A Prospective and Retrospective Observational Study of Multidrug-Resistant Patient Outcomes With and Without Ibalizumab

Inclusion Criteria:

1. The patient is Heavily treatment-experienced (HTE), with limited treatment optionsand a history of treatment failure;

2. Based on recent or historical resistance assays and ARV history, patients must havedocumented Multi Drug Resistant (MDR) HIV-1 (e.g., laboratory report and documentedpast ARV treatment);

3. Received an appropriate HIV-1 resistance assay (genotypic or phenotypic testing) todevise an OBR (which may include an investigational ARV treatment) or will receivean appropriate resistance assay prior to initiating ibalizumab treatment;

4. Provide signed and dated informed consent to the Investigator, indicating that thepatient (or, legally acceptable representative) has been informed of all pertinentaspects of the study, and is capable of understanding and willing to comply with theregistry requirements. The consent will request to access the patient's medical,hospital, pharmacy, and vital statistics records as appropriate, as well ashistorical medical data for the full retrospective time period (01 May 2018 toenrollment). Further, consent will be provided for access to all availablehistorical resistance and ARV treatment data;

5. ≥18 years of age or older at the time of screening;

6. Provide information on at least one alternate contact person of their choice (primary care physician, close relative or emergency contact) who can be contacted,should the patient be lost to follow-up over the course of the study;

7. Acknowledgement that in the event of their death, additional information can beobtained by contacting their primary care physician, a close relative, emergencycontact or by consulting public or external databases (death registries, obituarylistings) when available and verifiable. This is to be done in accordance with localregulatory requirements and laws;

8. Exceptionally, patients who may have started ibalizumab outside of the approvedindication can also be included in Cohort 2 of the registry at the discretion of theinvestigator, provided they determine clinical utility.

Exclusion Criteria:

1. Pregnant or breastfeeding;

2. Unable to provide informed consent;

3. Hypersensitivity to ibalizumab or any of the excipients in ibalizumab;

4. Previous ibalizumab experience (Cohort 1 only)

5. Previously enrolled in Cohort 2 of this registry.