Dear Sujit,
Kindly see my responses below.
1) What is the PICO for the Purpose 1 study?
Population - cisgender women and adolescent girls aged 16-25 years
Intervention - twice yearly injectable lenacapavir
Comparison - once daily oral Descovy and once daily oral Truvada
Outcome - HIV prevention in cisgender women
2) Are the outcomes prevalence or incidence figures? The outcomes are incidence figures since the drugs administered were to prevent the cisgender women from contracting new HIV infections.
3) Calculate a difference figure.
Incidence rate difference = incidence rate (exposed) - incidence rate (unexposed)
Incidence difference (Truvada vs Lenacapavir) = 0.00 per 100 person-years - 1.69 per 100 person-years = -1.69 per 100 person-years
4) How many people need to switch from Truvada to lenacapavir to avoid one additional HIV infection? 100 people
5) What is the cost of #4? $42,250 per person per year*100 = $4,225,000 per year
A second trial, conducted in six other countries, including Brazil and the United States, is assessing the effectiveness of lenacapavir in men who have sex with men, in transgender people and in those who use injection drugs.
6) For whom do you think the Purpose 1 study results are more likely to be generalisable? And for whom are the results are the results less likely to be generalisable?
I think the Purpose 1 study results will not be generalisable to the participants in the second trial but will be less generalisable to those who took part in the second trial because the risks are different for the different population groups.6b) For the latter group, would you recommend running a new trial?
I would recommend running a new trial, based on availability of funds, since the results of the first trial may not be applicable to them. Also, both the intervention and control groups will receive an effective medication that is approved for use.
Let me know what you think.
Best,
Anne.
