Long-acting Cabotegravir Injectable Pre-exposure Prophylaxis for People Who Inject Drugs

This is a Phase IV open-label single arm implementation study of the on-label use of an FDA approved drug, cabotegravir, as long-acting, injectable HIV pre-exposure prophylaxis (CAB-LA) among people who inject drugs. All enrollees will be prescribed CAB-LA based on CAB-LA's FDA approved indication, which is sexual risk of HIV transmission. Investigators will recruit participants from two sites in Boston, Massachusetts. The target study sample size is 100 participants.

Recruitment will be primarily by clinician referrals and medical records review at each site.

The study team will screen potential participants at both sites and assess their initial eligibility. Participants will be eligible to participate if they meet the inclusion and exclusion criteria. If an individual consents to participation, a 4th generation antibody/antigen (Ab/Ag) screening test (rapid or lab-based) and a confirmatory HIV-1 RNA test will be sent. If the HIV Ab/Ag screening test is negative, individuals will be enrolled.

Once a participant is enrolled, the participant will return 0-7 days later to complete a medical evaluation by a medical provider who will prescribe CAB-LA, and the participant will complete an enrollment survey. After the enrollment survey, participants will receive the first CAB-LA injection according to label instructions. The second injection visit will occur 1 month after the first injection. Thereafter, CAB-LA will be administered every 2 months for three additional doses. Thus, participants will remain in the study for seven months. CAB-LA for the study is supplied by ViiV Healthcare Ltd.

At each CAB-LA injection visit after the first one, participants will be asked to complete a short survey. A longer survey will be administered at the final study visit for each participant regarding acceptability of the intervention.

At each follow-up study visit prior to CAB-LA injection, HIV testing will be performed using both a screening Ag/Ab test and a confirmatory HIV-1 RNA test (if a blood sample for RNA testing can be obtained). If the screening HIV Ag/Ab test is positive, the CAB-LA injection will not be administered, and the participant will be withdrawn from the study and referred for HIV treatment. If the confirmatory HIV-1 RNA test returns positive from any study visit, including from the pre-enrollment sample, the participant will be withdrawn from the study and referred for HIV treatment. For any participant who is diagnosed with HIV during the study period, additional testing for antiretroviral drug resistance, including integrase strand transfer inhibitor resistance, will be collected, and the patient will be referred to HIV care.

Participants will also be screened for STIs (gonorrhea, chlamydia, and syphilis), HBV, and HCV at enrollment and at the time of the 3rd and 5th injections.

In addition to receiving CAB-LA, each participant will also receive support services while participating in the study. Specifically, participants will be connected with a PrEP Navigator who will work with participants between visits to provide support, education, and coordinate visits. The PrEP navigator will be a trained non-provider who can provide counseling about the risks and benefits of PrEP, discuss participant concerns, assist in coordinating clinic visits, and facilitate connections to medical care if needed. In addition, incentives for phlebotomy ($20) and appointment attendance ($20) will be provided to all participants. Transportation assistance for study appointments will also be provided.

After the study, participants will transition from study-supplied CAB-LA to commercially-available CAB-LA.

Inclusion criteria

• HIV Ab/Ag test (lab-based or rapid) negative at time of enrollment
• ≥18 years old
• Able to provide informed consent
• Have injected non-prescribed drugs within the past 6 months
• No prior history of receiving cabotegravir (Note: prior or active use of non-CAB PrEP ([FTC/TDF or FTC/TAF]) at screening is allowed, but participant will need to indicate that they prefer to switch to injectable PrEP).
• PrEP provider deems cabotegravir use to be appropriate per the applicable prescribing information prior to enrollment in the study.

Exclusion criteria

• Pregnant or breastfeeding people. Should a participant become pregnant, the treating physician will discuss with the participant whether to continue study medication, taking into consideration the risks and benefits of continuing cabotegravir compared with the risk of switching to an alternative recommended PrEP regimen.
• Has not had vaginal or anal sex in the past 6 months
• HIV indeterminate or positive test result during screening and prior to initiation of CAB PrEP
• Already diagnosed with HIV
• Taking any of the following medications: Carbamazepine, Rifampin, Oxcarbazepine, Rifapentine, Phenobarbital, Phenytoin