Investigational HIV integrase inhibitors in phase I and phase II clinical trials

Introduction: To date, three HIV integrase strand transfer inhibitors (INSTIs), i.e. raltegravir, elvitegravir and dolutegravir, have been approved for clinical use. Recent research has focused on new integrase inhibitors including those targeting non-catalytic sites of HIV integrase.

Areas covered: This paper reviews two investigational INSTIs in phase I and II clinical trials, bictegravir (BIC) and cabotegravir (CAB), as well as an investigational noncatalytic integrase inhibitor (NCINI) termed BI 224436.

Expert opinion: Data from phase I and II clinical trials demonstrate that CAB has good efficacy and is well-tolerated. CAB is promising because it can be formulated both orally and as a long-acting (LA) injectable for treatment and prevention of HIV infection. Since LA-CAB formulation offers the possibility of favourable dosing, it may help individuals who struggle with adherence issues. BIC also represents a promising safe, effective and well-tolerated drug that can be administered as a single once-daily regimen in coformulation with emtricitabine and tenofovir alafenamide (FTC/TAF). Ongoing phase III trials should clarify optimal doses and reveal the potential clinical advantages of these new drugs and formulations over other current regimens. Exploration of novel HIV integrase inhibitors acting through mechanisms different from those of INSTIs is still needed.