Defining Ts and Ss PrEP Dosing (2 of 8)

Author’s Note

3/26/18

2nd entry of 8 (1. Intro, 2. Definition, 3. Research, 4. Origins, 5. Rationales, 6. Critiques, 7. Implications, 8. Conclusion)

****

What does “The Ts and Ss” mean?

“I’m doing the Ts&Ss+ where I’m supplementing that baseline regimen [4 doses per week] with additional doses when I’m more active…When I do have sex where there’s a risk of HIV transmission, I will add in an extra pill or two on a MWF, just to be extra sure.”

–Andrew Leavitt, cis, gay, white, male PrEP user and advocate in Dublin, Ireland

“Ts & Ss [is]…the reduced dose… 4 times a week…[But] Ts and Ss and event-based [doses] are not suitable for vaginal sex. [People with front holes n]eed [a] longer period to get up to protection level and [it] needs to be taken daily. [More here on the subject.] [It’s n]ot relevant for me but may be for some trans men. Anal is the same for cis/trans men/women.”

–Jamie, white, trans, queer, male PrEPster and advocate in Birmingham, the second largest city in England

“I use 4 a week but follow a two Ts and two Ss pattern (Tues, Thurs, Sat + Sun – as it’s easy to remember).”

-Davis*, cis, white, gay, male PrEPster, academic, and advocate in London, England

“‘[O]nce you have built up a baseline distribution of the drug, i.e. … 7 day[s of doses], reducing to Ts + Ss dosing to maintain a baseline, then[,] after a high risk exposure, …[A]djusting the regime to daily for 48hours post-event, [like] the iPergay dosing strategy [is]’ …Exactly what I do[. I call it] Ts and Ss “Plus”[.]”

-Juan*, cis, white, gay, male PrEP user and advocate in Spain:

“I combine “4 pills per week” with on-demand dosing according to the IPERGAY regimen…I take 4 pills a week as the ”standard“ (Mondays, Wednesday, Fridays, Saturdays). …Now, IF I actually have sex, and if that sex actually requires PrEP, then I “turn on IPERGAY dosing”, and would add in pills on the days that I normally wouldn’t take pills.”

–Nicholas Feustel, cis, white, gay filmmaker, PrEP user, and activist in Hamburg, Germany

(*Pseudonyms are used for some people who preferred them when they gave consent to be quoted for this blog post series.)

Looking at the personal definitions characterized above, their relevant through-lines become clear:

• Anal sex risk exposure among trans and cis men who have sex with men (MSM),
• Four doses per week – usually on Tuesdays, Thursdays, Saturdays, and Sundays, – and

• Flexible dosing, based on fluctuating sex patterns as well as daily- and IPERGAY post-sex dosing/efficacy data.

Now, when you compare the through-lines of those testimonies above to the instructions given to participants in the IPERGAY on-demand PrEP trial among cis MSM as well:

“Participants were instructed to take a loading dose of two pills of TDF-FTC or placebo with food 2 to 24 hours before sex, followed by a third pill 24 hours after the first drug intake and a fourth pill 24 hours later. In case of multiple consecutive episodes of sexual intercourse, participants were instructed to take one pill per day until the last sexual intercourse and then to take the two postexposure pills. When resuming preexposure prophylaxis, participants were instructed to take a loading dose of two pills unless the last drug intake was less than 1 week earlier, in which case they were instructed to take only one pill[,]”

The through-lines of anal sex risk, at least 4 doses in a week, and flexibility around dosing and changing sex patterns becomes even more clear.

Now, according to IWantPrEPNow.co.uk, a website set up in 2015 by U.K. HIV prevention advocate Greg Owen, “4 pills per week usually involves taking a pill on Tuesday, Thursday, Saturday and Sunday hence ‘the Ts and Ss.'” That makes it a nondaily PrEP strategy of the “weekly-based dosing” or “routine plus event based dosing” variety by one estimate, depending on whether or not a user only doses four set days per week or, like Leavitt and others above, supplements the four doses with more during periods of greater activity and/or risk potential.

Recently translated into a handy-dandy tutorial video by Owen, this dosing advice tidbit also points out that the cleverly and mnemonically named strategy:

A.) is only suitable for anal sex,

B.) comes with a lead-in of 7 daily doses, and

C.) is an adaptation of research from the IPREX trial of daily PrEP as well as the IPERGAY trial of on-demand PrEP (also called event-based or intermittent PrEP), both among cisgender men who have sex with men (cMSM) and transgender women engaged in anal sex.

IPREX PrEP trial lead investigator Robert Grant aptly presaged this emerging adaptive trend while explaining in 2015 his own motivation for exploring, in research nondaily approaches to PrEP dosing. He stated at the time:

“[W]e really know that anything that we can offer in medicine works best if people can adapt it to their lives and to their complex living situations. And that is … very true for sexual health. We really need…biomedical approaches that people can use and adapt for themselves.”

And if you asked Andrew Leavitt, he’d agree, though he might put it in a slightly different light:

“Personally[,] I think this kind of community-based innovation is very much in keeping with the ways the LGBT community has responded to HIV since the beginning of the epidemic. Thirty-five years ago recommending condoms to prevent HIV (or rather, the mysterious whatever it was that was killing people) was not scientifically proven, and wasn’t widely endorsed. Fifteen years ago, the idea that HIV-negative people could take ARVs to prevent HIV seemed a bit crazy—but gay & bi men were already doing it. Likewise, many men were making informed decisions about risk reduction based on the understanding that effective treatment prevents transmission for the last 10+15 years, although the evidence has only recently accumulated to the point where this is becoming universally recognised.”

In that way, the Ts and Ss PrEP dosing strategy is a textbook example of adapting biomedical research data to the complex lives of real people… But what’s the supporting data?

3/26/18

2 of 8 (previous entry)

Next up, the data underpinning Ts and Ss PrEPping…

…

[3/1/19 UPDATE: Added other testimonials to Leavitt’s. Added IPERGAY definition. Added more “adaptation” language. Other slight edits. 6/17/10 UPDATE: Added Jamie dosing caveats. ]