Merck’s DOR/ISL demonstrated non-inferiority and a similar safety profile to comparator

US pharma giant Merck & Co (NYSE: MRK) has presented positive results from two pivotal Phase III trials of the investigational, once-daily, oral, two-drug regimen of doravirine/islatravir [DOR/ISL (100mg/0.25mg)] in adults with HIV-1 infection that is virologically suppressed on bictegravir/emtricitabine/tenofovir alafenamide [BIC/FTC/TAF (50mg/200mg/25mg)] in trial MK-8591A-052 ) or antiretroviral therapy [baseline antiretroviral therapy (bART)] in trial MK-8591A-051.

Merck said that, in both trials, DOR/ISL met the primary efficacy success criterion for non-inferiority to comparator antiretroviral therapies and primary safety objectives at Week 48. The findings will be shared in late-breaking oral presentations at the 32nd Conference on Retroviruses and Opportunistic Infections (CROI) being held in San Francisco, USA.

In the double-blind trial MK-8591A-052 (Abstract #204A), results for the primary endpoint (HIV-1 RNA ≥50 copies/mL) showed that 1.5% of participants who switched to DOR/ISL had a viral load of ≥50 copies/mL at Week 48, compared to 0.6% on BIC/FTC/TAF (treatment difference 0.9%, 95% CI -1.9, 2.9). At Week 48, 91.5% of participants who switched to DOR/ISL maintained viral suppression (HIV-1 RNA <50 copies/mL) compared to 94.2% of participants who continued receiving BIC/FTC/TAF (treatment difference -2.6%, 95% CI -7.1, 2.6; secondary endpoint).