100% HIV prevention for women

[jimbob]

https://www.nejm.org/doi/full/10.1056/NEJMoa2407001

Very promising

Twice-Yearly Lenacapavir or Daily F/TAF for HIV Prevention in Cisgender Women

Abstract
Results
Among 5338 participants who were initially HIV-negative, 55 incident HIV infections were observed: 0 infections among 2134 participants in the lenacapavir group (0 per 100 person-years; 95% confidence interval [CI], 0.00 to 0.19), 39 infections among 2136 participants in the F/TAF group (2.02 per 100 person-years; 95% CI, 1.44 to 2.76), and 16 infections among 1068 participants in the F/TDF group (1.69 per 100 person-years; 95% CI, 0.96 to 2.74). Background HIV incidence in the screened population (8094 participants) was 2.41 per 100 person-years (95% CI, 1.82 to 3.19). HIV incidence with lenacapavir was significantly lower than background HIV incidence (incidence rate ratio, 0.00; 95% CI, 0.00 to 0.04; P<0.001) and than HIV incidence with F/TDF (incidence rate ratio, 0.00; 95% CI, 0.00 to 0.10; P<0.001). HIV incidence with F/TAF did not differ significantly from background HIV incidence (incidence rate ratio, 0.84; 95% CI, 0.55 to 1.28; P=0.21), and no evidence of a meaningful difference in HIV incidence was observed between F/TAF and F/TDF (incidence rate ratio, 1.20; 95% CI, 0.67 to 2.14). Adherence to F/TAF and F/TDF was low. No safety concerns were found. Injection-site reactions were more common in the lenacapavir group (68.8%) than in the placebo injection group (F/TAF and F/TDF combined) (34.9%); 4 participants in the lenacapavir group (0.2%) discontinued the trial regimen owing to injection-site reactions.

[Martin Y]

That's simultaneously amazing good news (no infections at all in the 6-monthly injections group) and depressing (during the trial period, 1% of these young women got infected with HIV). How long did the trial run for?

[Grumble]

That's simultaneously amazing good news (no infections at all in the 6-monthly injections group) and depressing (during the trial period, 1% of these young women got infected with HIV). How long did the trial run for?

It’s 2% in the control arm (current best practice) and 2.4% generally in the group (presumably including some who dropped out), 0% in the treatment arm.

[Martin Y]

Yes, I saw that but I didn't see anywhere how long the trial ran for.

[Gfamily]

Yes, I saw that but I didn't see anywhere how long the trial ran for.

Taking the 'no treatment ' group: 1.49% contracted HIV, and as that is expressed as '1.69 per 100 person years', it suggests it was about over 10½ - 11 months.
Similar for the F/TAF group.

But that seems unlikely (maybe it was 12 months, but there may be a 4-6 week period in which HIV won't be detected).
Basically, I dunno either

[Martin Y]

Since the seemingly effective treatment is twice-yearly injections, and a few are noted to have dropped out after reactions to the injection, you might presume the trial period was more than just one such treatment. But as you say, the infection rates expressed as a percentage of participants is a bit lower than the same figure expressed per 100 person years which means the trial was less than a year.

Maybe the trial ended because the results are so stark it would be unethical to keep the control groups off the effective treatment.

[Gfamily]

Since the seemingly effective treatment is twice-yearly injections, and a few are noted to have dropped out after reactions to the injection, you might presume the trial period was more than just one such treatment. But as you say, the infection rates expressed as a percentage of participants is a bit lower than the same figure expressed per 100 person years which means the trial was less than a year.

Maybe the trial ended because the results are so stark it would be unethical to keep the control groups off the effective treatment.

a 12 month trial would have covered 2 treatments (one at start, and one at month 6) - and (I'd have thought) one at the trial end.

[Martin Y]

LOL! I seem to be having more than my usual amount of brain-fade.
Of course the first treatment would be at the start, not at month 6.