Considerations for PrEP for People Who Inject Drugs

We know that the efficacy of pre-exposure prophylaxis (PrEP) in people using drugs is lower than in men who have sex with men—mainly due to adherence issues. Despite the results of the phase III Bangkok Tenofovir Study showing that daily oral PrEP is effective among people who inject drugs (PWID), stigma and socioeconomic challenges continue to confound adherence. Therefore, it is important to emphasize adherence to our patients who use drugs. But how can we help them achieve it?

Adherence
Healthcare professionals know that it is difficult to take an oral treatment every day. Because drug use often occurs daily, on-demand PrEP may be even more challenging. On-demand PrEP requires strictly following the prescribed dosing regimen without missed doses. If a patient misses doses, they will not be protected against the risk of HIV acquisition over the long term. In fact, there are very little data on whether on-demand PrEP dosing is effective in PWID. For these reasons, for PWID we recommend daily oral PrEP or long-acting PrEP, not on-demand PrEP.

Personally, as PWID are prone to missing oral doses due to their drug use and competing priorities, I think this is a perfect setting for long-acting PrEP. Because the biggest factor associated with PrEP efficacy is adherence, injectable, long-acting PrEP may be a good option.

However, injectable PrEP does require that patients return regularly for injections, and data for long-acting cabotegravir (CAB) specifically in PWID are lacking. In France, injectable CAB currently is used in the research setting only, as it is not yet widely available (but will be within a few months). That’s why we are implementing research projects and interventions to see how we can better design interventions with injectable PrEP to reach the highest number of PWID.

Access
Unfortunately, in most clinical settings we think about PrEP for men who have sex with men and less commonly for use in PWID. To overcome this barrier, healthcare professional training should include information on PrEP for PWID, and more information about PrEP should be made directly available to PWID.

One challenge is that PWID may not regularly come to healthcare settings, so we must go to them. One example is an outreach program where we would provide PrEP to opioid substitution therapy centers that already have close contact with the community of PWID. At some of these centers, the physician comes once per month only to renew prescriptions, and it is the peer educators, social educators, and nurses who provide patients with opioid substitution therapy, PrEP, and information on harm reduction.

I also think implementing PrEP programs in conjunction with the mobile teams that deliver harm reduction tools to PWID in the field would improve access to PrEP. Because they can deliver methadone, they should be able to deliver PrEP. I think implementing specific PrEP interventions will be possible by providing training to the care providers, providing information to PWID, and delivering the PrEP (especially long-acting PrEP) along with the opioid substitution therapy. Of note, clinically significant drug interactions are unlikely between emtricitabine/tenofovir disoproxil fumarate, emtricitabine/tenofovir alafenamide, or CAB and methadone or buprenorphine.

Some people who use drugs do not inject the drugs—they smoke them. Although the risk of acquiring HIV is lower with smoking drugs, these people may engage in sexual relationships without any harm-reduction strategies. Therefore, we also must think about drug use in conjunction with sexual risk.

Current CDC recommendations are that all sexually active adolescent and adult persons should be informed about PrEP. PrEP is recommended for men and women who are at risk of HIV acquisition through sexual behaviors and for PWID at risk of HIV acquisition. We may think that because they do not inject drugs, PrEP should not be provided, but because of their sexual relationships, PrEP should still be considered.

Your Thoughts?
In your community, which strategies are used to get PrEP to PWID and to support adherence?