What 96-Week Data Reveal About DOR/ISL in Diverse Patient Populations

Long-term outcomes from phase 3 switch studies (MK-8591A-051 and -052) provide important insight into the durability of viral suppression with doravirine/islatravir (DOR/ISL), reinforcing its potential as a stable, long-term maintenance strategy. At 96 weeks, rates of virologic suppression remained consistently high—exceeding 90% across treatment groups—demonstrating sustained efficacy well beyond initial 48-week benchmarks. Notably, there were no significant new safety concerns or signals of emerging adverse events over time, supporting the regimen’s tolerability in extended use.

These findings are particularly meaningful in the context of historically challenging patient populations. Subgroup analyses showed that individuals entering the trials with high baseline viral loads or low CD4 counts—groups often associated with poorer outcomes—still achieved strong virologic suppression rates. Although isolated cases of treatment-emergent resistance were observed, these were rare and occurred primarily in patients with extremely high viral loads, underscoring the importance of careful patient monitoring.

Importantly, the data suggest that DOR/ISL performs comparably to established regimens even in more advanced disease states, helping to address a key concern for clinicians considering non-INSTI options. The consistency of suppression across both standard and higher-risk populations adds to the growing body of evidence supporting the regimen’s robustness.

Overall, the 96-week results highlight DOR/ISL as a durable and effective option for maintaining viral suppression, with performance that holds up across diverse clinical scenarios. These findings strengthen the case for its inclusion in future treatment strategies, particularly as clinicians seek regimens that balance long-term efficacy with improved tolerability.