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  • 1.  repeatedly delayed LA-CAB or CAB-RPV

    Posted 04-05-2024 12:03

    Hi all,

    I want some more opinions about a question which is posed to me a lot. Let's say that a patient is doing well on q 8 week CAB-RPV and, to make it simple, let's say that they're already several months into it. [Same question could work for a PrEP patient on LA-CAB.] Now imagine that they miss their target injection window and receive a delayed dose, not 8 or 9 weeks from the last dose, but 11 weeks. Fine, they get the late dose, and then they resume a q8w schedule. Therefore, instead of intervals of 8w-8w-8w, they've now had 8w-11w-8w. 

    My question is, what do you do about patients who go through this repeatedly? If someone is late (but less than a month late) multiple times, the prescribing instructions would just have us give a late injection and resume the q8w schedule each time. But is this enough? (For example, a patient could end up with intervals of 8w-11w-9w-10w-9w-10w, meaning they got 6 injections over 57 weeks, whereas if each dose fell within the 7-9w window they would get to 6 doses over 42-54 weeks.) Would you, at some point, consider shortening the interval, ie insisting on a one-month interval before going back to 2-month, even though they're never >1 month from target date? Or when resuming, would you schedule the next injection closer to the 7w end of the target window to try to compensate? As far as I know, there isn't data to support a rigid requirement for exactly 6 injections over 12 months, but the fact that q1 month injection seems to confer a lower risk of failure than q2 month injection makes me concerned about folks whose doses are always on the late end or slightly overdue.  

    I know an obvious answer is going to be, "If the patient cannot present consistently at 8 week intervals, they shouldn't be on LAI," but let's just agree that this hypothetical scenario represents harm reduction and there's some good reason that LAI is the best option.

    I should also note: I'm assuming that the opposite case, of a patient whose schedule for some reason always favors the 7w end of the interval, wouldn't suffer any serious consequences. I wouldn't argue if they wanted to schedule that way and were tolerating it. But the +/- 1 week really does allow a big range if we consider the "total annual dose," and especially for very long-term use and given the long tail, I wonder whether this begins to make significant differences.



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    Julia Cooper MD, AAHIVS
    New York, NY
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  • 2.  RE: repeatedly delayed LA-CAB or CAB-RPV

    Posted 04-05-2024 12:33

    Julia:

    Prior to the decision of using CABENUVA, patients should have a good discussion of importance of having every 2 months target day IM injections of CABENUVA. We have to stick on the target date, not every 2 months. For example, target date is 15th of the months, patient has been stable on CABENUVA for at least 4 doses and delayed to 30th of the month to get IM shots. The next target should be still 15th day +- 7 days of the month, not 30th +-7 days of the month. I would try to have 15th day - 7 days as the next appointment, so it will have 2 weeks to get patient in for IM shots without missing the target period. Key is "not to change target date" unless there is a special circumstance that requires re-set the target date, i.e., off the IM injections > 1 months that requires re-boost in 1 month. 



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    Chiu-Bin Hsiao
    Allegheny General Hospital - Positive Health Clinic
    Pittsburgh PA
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  • 3.  RE: repeatedly delayed LA-CAB or CAB-RPV

    Posted 04-05-2024 15:00

    Thanks! I'm very grateful for the response. The phrase "resume the every two-month schedule" or "follow the 2 month dosing schedule" doesn't actually make it obvious whether the original schedule is to resume as if the delay had never happened, or if the injections are to start again two months from the late injection, and I have heard providers interpret it each way. The same phrase is used in ViiV's prescribing info, on the academy's long-acting resource center and the national curriculum. However, the ViiV product monograph (https://viivexchange.com/content/dam/cf-viiv/viivexchange/en_CA/open/pdf/cabenuva.pdf) also says on page 6:



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    Julia Cooper MD, AAHIVS
    New York, NY
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  • 4.  RE: repeatedly delayed LA-CAB or CAB-RPV

    Posted 04-06-2024 11:52

    https://journals.sagepub.com/doi/epub/10.1177/20499361231214626

    this article provides a good description of practical dosing schedule in practical settings. 



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    Chiu-Bin Hsiao, MD, FIDSA, AAHIVS
    Allegheny General Hospital - Positive Health Clinic
    Pittsburgh PA
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  • 5.  RE: repeatedly delayed LA-CAB or CAB-RPV

    Posted 04-07-2024 02:36

    I've gone back and forth with colleagues about the interpretation of "continue every 2 months thereafter" for a dose missed by <1 month, so I'm glad to see this conversation playing out here.  

    Because of the long half-life of Cabenuva's components we prioritize the number of doses over time, preferring to maintain the original TTD (target treatment date) in the case of doses missed by <1 monthHowever, for reassurance I reached out to a medical scientist at Viiv for their team's opinion and they agreed that missing a dose by <1 month should not "reset" their TDD. 

    Thanks for sharing this article. It seems to also support that same position (despite maintaining some of the ambiguity), stating "keeping the original TTD is recommended, but establishing a new TDD is also an option, if required." 



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    Brandon Ross
    AIDS Healthcare Foundation
    Oakland CA
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