What the noninferiority bargain bought
Opti-DOR randomised 600 previously untreated adults at two South African sites. At week 48, HIV RNA was below 50 copies per millilitre in 266 of 299 participants receiving doravirine, lamivudine and tenofovir disoproxil fumarate, and in 273 of 301 receiving dolutegravir, emtricitabine and tenofovir alafenamide. The difference was 1.7 percentage points, with a 95 per cent confidence interval from -6.6 to 3.1. Because the prespecified noninferiority margin was -10 points, the primary endpoint was met. This design does not say that the doravirine regimen was superior. It says that viral suppression did not fall behind by more than the margin the trial had accepted in advance.[1]
The return appeared in weight gain. Median gain over a year was 3.0 kilograms in the doravirine arm and 5.0 kilograms in the dolutegravir arm. The difference of -2.0 kilograms had a confidence interval from -3.0 to -1.0 kilograms and a P value below .001. This is not a clean comparison of two active drugs alone because the arms also contain different forms of tenofovir. Even so, the clinical question is concrete: can people vulnerable to weight gain on an integrase inhibitor and tenofovir alafenamide keep viral suppression with a lighter option? A median two-kilogram difference will not mean equal benefit for everyone, but it is large enough to enter a drug decision for someone at high cardiometabolic risk.[1]
The other face of the trade
Bone mineral density moved in the opposite direction. Hip density fell 2.1 per cent in the doravirine arm and 0.5 per cent in the comparator; spine density fell 3.2 per cent against 1.3 per cent, with P below .001 for both comparisons. The leading candidate is the older tenofovir disoproxil fumarate used alongside doravirine, since tenofovir alafenamide replaced it in many regimens partly for its bone and renal profile. The trial did not isolate individual components, however, so the loss cannot be assigned to one drug alone. Smaller weight gain can also change mechanical loading and measured density. The result places a bone question beside the attractive weight headline.[1]
The population to whom this trade applies is also narrow. Participants were adults starting treatment and were followed for only 48 weeks. People already suppressed on another regimen, children, pregnant patients and durability beyond one year are absent from the result. The investigators therefore position doravirine as an option for people likely to suffer complications from weight gain, not as a universal replacement for dolutegravir. Strict adherence also matters because missed doses can increase resistance risk. If the separation between bone-density curves settles by week 96, the weight advantage becomes a safer bargain. If it continues to widen, less weight gain may not produce the better overall outcome for a person who already carries a fracture risk.[1]