Meds, Mind, Body & Benefits > Questions About Treatment & Side Effects

Using tenfovir (Viread) with abacavir (Ziagen)

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newt:
As promised I said I would start a thread on this.

Some info on tenofovir (TDF) + abacavir (ABC) when used together.

First off, triple-nucleoside combos of tenofovir , abacavir and another nuke (3TC, ddI etc) have a high rate of failure. Do not use except for maintenance if you already have a viral load <50, and not as a switch from another combo (says the UK guidelines). Several studies, eg ESS30009, have demonstrated this, and the European Medicines Evaluation Agency, for one, issued a treatment alert (reported in many places including here).

Otherwise, some encouraging studies...

Clinical success rate of antiretroviral regimens utilizing a  tenofovir/abacavir/kaletra backbone in HAART experienced patients, reported on AEGiS, notes using a boosted PI + TDF + ABC is effective, concluding:

""TDF/ABC/LPV [Kaletra] regimens in HAART experienced patients had a surprisingly high success rate of 84%. Furthermore, all failures had low level viremia (VL< 750). Prior exposure to PIs and mutations did not effect outcome. To what degree TDF and ABC are contributing to LPV's effects in the success of this regimen is unknown. A prospective study needs to be done as TDF/ABC/LPV remains a highly used regimen and is now recommended as a salvage regimen in the revised WHO 2003 guidelines.""

As do many other studies...

Negotiating the Nucleosides on the Path to Simplicity: Medscape original (requires login) or Google cache version (no login) reports:

"The Spanish RECOVER Trial was a prospective evaluation of virologically suppressed patients who switched from any NRTI to tenofovir. Of 1350 subjects enrolled in this study, 101 were switched to a regimen including abacavir and tenofovir; 51 of these received the 2 drugs as parts of a triple-NRTI regimen, 30 received abacavir/tenofovir with an NNRTI, and 20 with a protease inhibitor (PI). Eighty-seven percent of patients were on their third or greater antiretroviral regimen. After 24 months, only 3 patients receiving NNRTI- or PI-based regimens had virologic failure, all of which was attributed to noncompliance. By contrast, 8 of 51 (16%) patients receiving triple-NRTI regimens had virologic failure."

And:

"Ward reported a retrospective review of 138 patients who received abacavir/tenofovir in a triple-NRTI regimen in a single practice. As in RECOVER, the majority of these patients were already virologically suppressed and switched to this combination for reasons of toxicity; however, patients who received this combination as initial therapy or as a new regimen after failure were also included. Seventy-four percent of patients had previous NRTI resistance. After a median of 26 months of follow-up, only 8% of patients experienced virologic failure; another 9% had persistent low-grade positive viral loads. "

From NATAP: Tenofovir+Abacavir: is there a risk for K65R associated increased failure ? reports good results in various scenarios, albeit with small numbers.

Etc etc

Set agains this are other studies showing increased rate of K65R mutation on people using tenofovir+abacavir with NNRTIs like Sustiva, less so with boosted protease inhibitors, though this is complicated to analyse because you need to differentiate the people who used tenofovir as a first-line drug (very very low chance of K65R), people who switch with viral load <50, people with treatment experience (do worse) plus the adherence factors (do worse).

My doc will prescribe tenofovir+abacavir  with boosted PIs but not with NNRTIs except as part of salvage.

There probably isn't an interaction between tenofovir and abacavir. i-Base first reported on the non-interaction in 2003. Here's a more recent abstract which concludes:

"...the combination of TFV and ABC was found to be additive with respect to inhibition of HIV replication. Addition of 3TC to the combination did not result in synergistic or antagonistic effects. CONCLUSIONS: The poor efficacy of the triple NRTI regimen of TDF, ABC and 3TC is probably not due to a metabolic drug interaction resulting in antagonism of antiviral activity."

My view: the picture is not simple, except for a big DO NOT USE for triple nuke combos including tenofovir+abacavir . The results are good in many studies for tenofovir+abacavir with boosted PIS and NNRTIs.

Article in normal English covering tenofovir+abacavir in a triple nuke combo

- mat

..okay so it's an "old" new thread, there you go..

Matty the Damned:
Hey Matt,

Thanks for this thread.

I used Abacavir/Tenofovir/3TC for about 12 months and the treatment failed. I missed only like 3-4 doses of abacavir in the 12 month period. I was given the combo because I couldn't tolerate efavirenz and I had liver issues so nevirapine was out.

I didn't learn until later (and from this site I think) that ABC/TFN/3TC is a deprocated combo because of the awful failure rate. I'm fairly lucky though. I've got high level resistance to 3TC (no biggy) and I'm resistant to Tenofovir too. I also ended up resistant to AZT, something which I've never taken.

Ah well. ;D

MtD

heartforyou:
Hey Matt,

I am on Viread (tenovifir), Abacavir (Ziagen), Epivir (3TC) and Viramune.

My doctor indeed told me it was a risky change when I did last year.
But it works very well and the side-effects are nihil.

Interesting thread.

Hermie

J.R.E.:
Hello Herman,

 I am glad you posted. I was wondering if you were on the same regemin.(we are on the same one) Glad that things are going well for you.


The Best-----Ray

heartforyou:
Ray,

When did you switch to this regimen?
Any side effects at all?

Hermie

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