HIV remains a major global public health concern, with 37.9 million people living with HIV, 770,000 HIV-related deaths, and 1.7 million new HIV infections in 2018.¹ Data presented at IDWeek 2019 highlight the ongoing efforts to improve HIV treatment and prevention options, including studies focused on key populations in the HIV elimination effort such as pregnant women, transgender women (TGW), and men who have sex with men (MSM).

Rapid initiation of antiretroviral therapy (ART) or ‘rapid start’ has been shown to improve retention in care and reduce time to virologic suppression. WHO and IAS-USA guidelines recommend rapid initiation, including same-day if the patient is ready, for those newly diagnosed with HIV.^2,3 However, same-day ART remains an investigational strategy in DHHS guidelines.⁴ Rapid start of ART inherently results in initiating treatment before baseline laboratory results are available, and boosted darunavir (DRV)-based regimens are among those recommended for first-line ART for patients with unavailable resistance data due to the high resistance barrier of DRV.^3,4 IDWeek 2019 data from the DIAMOND trial confirmed high rates of virologic suppression in patients starting DRV/cobicistat (COBI)/emtricitabine (FTC)/tenofovir alafenamide (TAF) within 14 days of diagnosis, regardless of baseline HIV-1 RNA, baseline CD4+ cell count, and time from diagnosis to enrollment.⁵ Of note, the investigators report that all patients achieved HIV-1 RNA < 200 copies/mL at Week 48, which is a level previously demonstrated to represent untransmissibility of HIV to uninfected sexual partners.⁶ This trial is the first phase III study of a single-tablet regimen for rapid initiation, and these results support this simplified strategy as an option for patients rapidly starting treatment.

One consideration for ART selection is the safety of various antiretrovirals (ARVs) in pregnancy. This has become a hot topic in the field recently as reports have indicated the potential for increased risk of neural tube defects with dolutegravir (DTG) exposure at conception.⁷ While the potential increased risk is smaller than initially indicated and the WHO has reconfirmed the use of DTG-based ART as a preferred option for all patients living with HIV, including pregnant women or women of childbearing potential, these data highlighted the need for increased safety monitoring of adverse pregnancy outcomes with different ARVs.⁸ A study at IDWeek investigated adverse birth outcomes for women with exposure to raltegravir, another integrase inhibitor, during pregnancy.⁹ The study analyzed 2550 prospective pregnancy reports with raltegravir exposure from an internal database and 2 ongoing cohorts of pregnant women with HIV-1 and found no increased risk of adverse birth outcomes compared to published rates for the general population. Importantly, there were no reports of neural tube defects among 765 periconception exposures.

The use of 3-drug ART regimens that include 2 nucleoside reverse transcriptase inhibitors (NRTIs) plus a third agent from another ARV class has been responsible for increasing the life expectancy of persons living with HIV to nearly that of the general population. However, since ART is life-long therapy, there remains a need to minimize long-term drug exposure to reduce toxicity and cost. One approach to reduce drug exposure is the use of 2-drug ART regimens, which are being investigated for their efficacy, safety, and barrier to resistance. Conference data reported at IDWeek confirm the efficacy of 2-drug ART in long-term follow-up and subgroup analyses. Specifically, the phase III GEMINI trials demonstrated that DTG plus lamivudine (3TC) was noninferior to DTG plus FTC/tenofovir disoproxil (TDF) in treatment-naive adults with HIV-1 at Week 96, and subgroup analyses revealed consistent efficacy across baseline disease and demographic characteristics with no treatment emergent resistance.¹⁰ Further, the phase IIb LATTE study demonstrated long-term efficacy of 2-drug cabotegravir plus rilpivirine as maintenance therapy in virologically suppressed patients through Week 312.¹¹ These results should be promising to clinicians who may have been hesitant to consider 2-drug ART until the availability of more long-term durability data.

Finally, conference data focused not only on treatment of persons living with HIV but the ever-important topic of HIV prevention through pre-exposure prophylaxis (PrEP). It remains unclear if the decline in new HIV infections in the United States over the past decade can be attributed to PrEP or treatment as prevention (TasP) uptake, as both have increased in multiple areas. A study analyzing CDC-published data from 105 US metropolitan statistical areas assessed the relative contribution of these prevention strategies and reported that the PrEP effect was significantly associated with declining HIV incidence, independent of TaSP.¹² Another outstanding question regarding PrEP is if FTC/TAF may provide better maintenance of renal function and bone health compared to FTC/TDF, similar to what has been reported for treatment of persons with HIV. Conference data from the phase III DISCOVER trial that assessed FTC/TAF compared with FTC/TDF in MSM and TGW at high risk for HIV infection demonstrated significantly better renal function and bone health through Week 48.^13,14 These data combined with previously reported data on the noninferiority of FTC/TAF compared with FTC/TDF as PrEP led to FDA approval of FTC/TAF as PrEP in adults who are HIV-negative and at-risk for sexually acquired HIV, which was announced by the FDA during IDWeek.^15,16 The current indication excludes those at risk of acquiring HIV from receptive vaginal intercourse due to the lack of established efficacy in this population. This new approval provides an important prevention option with the potential for fewer adverse outcomes for MSM and TGW, key vulnerable populations at-risk of HIV.

Detailed reporting of key data from the conference is available from multiple educational sources, such as Clinical Care Options’ conference coverage.