CROI 2022: NAMSAL study comparing DTG to EFV400 in Cameroon: week 192 results

Polly Clayden, HIV i-Base

Four-year follow-up of ART-naive adults living with HIV in Cameroon, who were randomised to either dolutegravir (DTG)-based or low-dose efavirenz (EFV400)-based treatment, suggests durability of both regimens long-term.

These findings from the NAMSAL study were presented at CROI 2022.

Drug resistance was reported at low rates in the EFV arm and in none of the DTG participants. Weight gain continued to be notable among women receiving DTG.

NAMSAL was an open-label, multicenter, randomised, phase 3 non inferiority trial, conducted over 96 weeks. This was extended as a prospective cohort until week 192.

Adults with viral load >1000 copies/mL were randomised (1:1) to receive DTG or EFV 400 – both combined with tenofovir-disoproxil-fumarate (TDF)/lamivudine (3TC).

The primary end point was the proportion of participants with viral load of <50 copies/mL at week 48.

Week 48 and 96 data showed DTG to be non-inferior to EFV. [2, 3] But DTG was associated with substantial and continuing weight gain, particularly among women.

At week 192, a slightly higher proportion of participants (ITT population) in the DTG arm, achieved viral load <50 copies/mL vs the EFV arm 214/310 (69%) vs 187/303 (62%): difference 7.3% (CI 95% 0.20 to 15.45), p=0.057.

In the fourth-year of follow-up there were five (2 in DTG and 3 in EFV 400 arms) new virological failures without related resistance mutations (NNRTI+/-NRTI).

At week 192, the mean weight gain was greater in women compared to men: women, DTG +8.0 kg and EFV 400 +5.0 kg (p=0.010); men, DTG +6.0 kg, EFV400 +4.0 kg (p=0.024). Incidence of obesity in the respective arms was: women, 17% and 11% (p=0.140) and men 26% and 3% (p<0.001).

The investigators noted that close cardiovascular and metabolic monitoring should be recommended to take into account risks related to weight-gain.

References

1. Mpoudi Ngole-Etame M et al. Long-term outcomes of dolutegravir and efavirenz-400 as first-line ART in Cameroon. CROI 2022.12–16 February. Virtual. Poster abstract 493.
   https://www.croiconference.org/abstract/long-term-outcomes-of-dolutegravir-and-efavirenz-400-as-first-line-art-in-cameroon/ (abstract and poster)
2. Clayden P. Dolutegravir non-inferior to low dose efavirenz in real-life African study conducted in Cameroon. HTB. 13 November 2018.
   https://i-base.info/htb/35235
3. Clayden P. Dolutegravir non-inferior to efavirenz at week 96 in the NAMSAL study but associated with substantial weight gain. HTB. 28 August 2020.
   https://i-base.info/htb/38778

This report was first published on 10 June 2022.