Importance of Sensitive TMA Testing

I think the importance of sensitive TMA testing has already been established early-on in treatment, as well as for  End of Treatment and post treatment. This article -- brought to my attention by "Willing" in another post -- suggests how important it is to continue sensitive TMA testing throughout treatment.

Basically what the study says is that detection of low level virus (below the limit of a PCR) can predict treatment failure. And conversely, UND by TMA can help predict SVR.

This was no doubt part of the reason that my doc wanted sensitive TMA's monthly during treatment (I tested via TMA  weekly before UND) and why a consulting doc -- when helping me to decide treatment length -- made it a point to mention that I was UND by TMA throughout treatment -- with the suggestion that in all likelihood the virus was gone for good.

Two good tests using TMA technology are "Heptimax" by Quest Diagnostic's Lab and "HCV RNA TMA QUAL" also by Quest. The latter should only be taken after you're UND by "Heptimax" since it will not produce a number, just either confirm UND status or not. LabCorp also has a very sensitive test using I believe PCR technology that would do the same thing.

BACKGROUND: In chronic hepatitis C patients with an initial virological response (IVR) during antiviral therapy (that is, HCV RNA becomes negative before week 16 of treatment) the significance of reappearing viraemia below the detection limit of PCR is not known. We studied this phenomenon in subsets of patients. METHODS: We assessed HCV RNA at weeks 16 and 20 of therapy by PCR and by more sensitive transcription-mediated amplification (TMA) in 23 patients with breakthrough or relapse and in 34 patients with sustained virological response (SVR). All patients participated in a high-dose-interferon induction study for difficult-to-treat patients. Therapy consisted of amantadine hydrochloride and ribavirin, combined with interferon-alpha2b induction during the first 6 weeks and thereafter combined with weekly pegylated interferon-alpha2b. RESULTS: Among the 57 IVR patients, we detected transient or persistent reappearance of low levels of HCV RNA in 10 of the 23 (43%) patients with eventual breakthrough or relapse; but in none of the 34 SVR patients. In 5 of 10 patients reappearing HCV RNA was only detectable by TMA. CONCLUSION: Reappearance of low levels of HCV RNA in patients with IVR predicts treatment failure
http://lib.bioinfo.pl/pmid:17591033

[jmjm530]

Another related paper on the importance of sensitive TMA testing. At this point, it seems clear that best to use sensitive TMA (or the equivilant) testing once treatment starts, periodically throughout treatment and after treatment.

http://www.hivandhepatitis.com/2007icr/aasld/docs/110907_a.html

Highly Sensitive HCV RNA Tests Required to Evaluate Treatment Response and Relapse Rates and to Create Individualized Treatment Strategies for Hepatitis C Patients

In order to improve individualized therapeutic strategies for patients with HCV infection, it is important to determine the most precise estimation possible of early virological response rates (EVR). The sensitive TMA test may be the best tool currently available to distinguish sustained from non-sustained responders (i.e., relapsers) at early stages of treatment.

In the current study, presented at the recent 58th Annual Meeting of the American Association for the Study of Liver Diseases (AASLD 2007) in Boston (November 2-6, 2007), German researchers evaluated whether TMA might be a better indicator to predict long-term outcome of anti-HCV therapy in genotype 1 patients who have undetectable HCV RNA according to the branched DNA (bDNA) assay.

In this 48-week study, 433 participants were randomized to receive either 1.5 mcg/kg pegylated interferon alfa-2b (PegIntron) plus 800-1400 mg ribavirin for 48 weeks (n=225, group A) or an individualized treatment duration (n=208, group B).

In the latter group, treatment duration was calculated based on the time required to become HCV RNA negative for the first time as defined by the bDNA assay (limit of detection 615 IU/mL) multiplied by a factor 6.

HCV RNA levels were quantified weekly until week 8, then at weeks 12 and 24. The more sensitive TMA test (limit of detection 5.3 IU/mL) was also prospectively assessed for all patients who were HCV RNA negative by bDNA. The different response groups were classified according to HCV RNA levels at weeks 4 and 12.

Results

    • The table shows the relevant data and refers to the relative relapse rates in group A and B at weeks 4 and 12 in relation to treatment schedule.

    • There is clear evidence for a high relapse rate in patients with a positive TMA, being more pronounced within the first 12 weeks of therapy when treatment duration was shortened in the individualized treatment group.

    • In contrast, patients who responded as early as week 4 as evidenced by a negative TMA test had relapse rates below 10% regardless of treatment group.

Response Groups  


Relative Relapse Rate (%)

Week 4
response


≥ log decline,
bDNA positive


36%
(all patients)


19%
(group A)


63%
(group B)

bDNA negative,
TMA positive


38%
(all patients)


22%
(group A)


49%
(group B)

bDNA negative,
TMA negative


4%
(all patients)


0%
(group A)


8%
(group B)

Week 12
response


≥ 2 log decline,
bDNA positive


77%
(all patients)


78%
(group A)


75%
(group B)

bDNA negative,
TMA positive


64%
(all patients)


56%
(group A)


69%
(group B)

bDNA negative,
TMA negative


20%
(all patients)


9%
(group A)


32%
(group B)

Based of these findings, the researchers concluded, "The application of the highly sensitive HCV RNA tests must be considered to be mandatory now because this new test helps to evaluate in a much more refined way treatment response as well as relapse rates and provides better clues for an individualized tailored treatment strategy."

"Our study clearly indicates that patients, even with a minimal amount of HCV RNA detected at week 12, can suffer from relapse rates greater than 50%," they continued. "These patients may indeed benefit when their treatment duration is adapted to their individual needs."

Charite, Campus Virchow Klinikum, Berlin, Germany; Medizinische Universitätsklinik, Frankfurt, Germany; Klinikum der Universität Würzburg, Würzburg, Germany; Hepatologische Schwerpunktpraxis, Berlin, Germany; Medizinische Universitätsklinik, Freiburg, Germany; Christian-Albrecht-Universität, Kiel, Germany; Universitätsklinik, Zürich, Switzerland; Medizinische Universitätsklinik, Bonn, Germany; Universitätsklinik Eppendorf, Hamburg, Germany; Essex GmbH, München, German.

11/09/07

Reference
T Berg, V Weich, G Teuber, and others. Importance of a Minimal Residual Viremia for the Relapse Prediction in HCV Type 1 Patients Receiving Standard or Individualized Treatment Duration. 58th Annual Meeting of the American Association for the Study of Liver Diseases (AASLD 2007). Boston, MA. November 2-6, 2007. Abstract (oral) 179.

[jmjm530]

"the time to HCV RNA-negativity by TMA (or other tests with similar sensitivity for HCV RNA detection) may be the best means of predicting likelihood of SVR, and serial testing for HCV RNA by TMA, the best means of predicting nonresponse"

http://www.natap.org/2006/HCV/080106_03.htm

[jmjm530]

LabCorp also has a couple of tests using very sensitive PCR technology -- Quantasure and Quantasure Plus. Quantasure is the most sensitive test with a sensitivity of 2 IU/ml. However, if you have a high viral load, you might be better off with Quantasure Plus because it has a wider dynamic range going up to 100 million IU/ml while Quantasure only goes up to 2 million.

-- Jim

[CockSparrow]

Jim
You might be interested in this from Clinical Care which kinda contradicts the need for more sensitive assays during Tx.

Higher SVR Rates Not Observed When More Sensitive PCR Assay (< 15 vs 50 IU/mL) Used to Detect RVR for Response-Guided Therapy in HCV-Infected Patients

http://tinyurl.com/36orsl

CS

[willing]

cs: those results seem to further refine the question of when high-sensitivity tests do or don't have clinical value (and thus justify their higher cost). I found the original AASLD abstract (1299) somewhat more readable than the clinicalcareoptions summary but regardless the point seems to be that the predictive power of an RVR(50) is as good as that of an RVR(15). My hunch is that this sort of result, which may be an attempt by Roche to salvage its longstanding COBAS AMPLICOR product won't make much difference as most physicians will switch their  one-size-fits-all-test from amplicor to taqman rather than trying to save some $ by puzzling out  whether there's any value to extra sensitivity at that point in tx.

This sea change will presumably be accompanied by a bit of anxiety : who's going to be willing to really take Gelderblom'07 to heart and given up on an otherwise successful tx because of a VL 5 spike at say 24?

nygirl: the study CS flagged was  based on re-analysis of blood draws from two previous studies which had been stored (at -70C). Do you think there's any chance the sample from your first post-EOT test was saved? Now that you've gotten to SVR it would be very interesting to recheck whether that was a false positive or a genuine post-EOT spike which was later eliminated.

[jmjm530]

I can see this is going to be a very slow death :)

[nygirl7]

I doubt they saved it - I can't think of any reason they did, I'm just glad it was WRONG!  I honestly believe that like Hepresearcher has suggested - it's happened too many times with people at about the same number to seem like an actual spike.  A spike I would believe (just from my opinion) would be higher but these all seem to be in the same range.........



:)

[willing]

nygirl - sorry, I missed HR's comments on this; was his take that it was a false positive? I agree it  seems unlikely they would have saved the vial, but who knows perhaps keeping the sample for a while in case re-analysis is requested is part of the protocol, a bit like saving bx tissue (and those big freezers are pretty cheap).  

Obviously it doesn't make any difference now (and congratulations again on your SVR!) but there are few occasions to so conclusively show a result  wrong as was the case there.

jim :  has this been hashed out at length already? I  must have missed those threads.

[jmjm530]

LOL. You're killing me (and I'm sure will continue to do so until they ban the older tests :))
---------------------------
BTW, re "HR" -- as you know, he's commented frequently on TMA false postives due to cross contamination, etc.  

However, recently he also put forth a comment in a thread on EOT interferon tapering, that goes something like this (his thoughts not mine) -- t

that if you don't taper off, your immune system may actually go into a negative state for a short while right after treatment until the natural immune system takes over.

During this "gap" let's call it, lies the possiblity of a relapse and therefore at least one reason why he recommends tapering off the Peg.  Using this logic (again not mine) I suppose it's possible that some of the "blips" post tx that later turn out to be UND may in fact not be false postiives, but the virus starting to break through during this window period. In NYGirl's case, the virus was finally suppressed by the natural immune system-- others might not be so lucky. Of course, it would be a lot easier to tell -- on the false positive issue -- if people would try and get their doctors to call the lab and re-run the test using the original blood, if enough is available.

-- Jim

[merryBe]

I just got my first TMA yesterday.

the week I spiked to 700,000 they said could not have been caused by the giant jaw/lymph infection I was having.

But the following week it was down to 523,000.

so who can believe what. If it was a nonreapnsive strain, why would it go back down when my other infection cleared?

anyway, had a TMA drawn....not sure I trust any of these tests...after all a 95% accurate rate...still leaves 5 % error.........and that does not tell you just how off those 5% errors will be now does it!!???
Mary

[jmjm530]

There is no clinical difference between 700,000 IU/ml and 523,000 IU/ml and, in fact, those values fall within the test variance itself. You should therefore view one test as confirming the other unless your physician suggest otherwise with cause.

-- Jim

[willing]

if you believe  some quasispecies are much more fit for survival (though quite possibly not for reproduction) than others, eg because of loss of epitopes that enable their detection (see discussion in thread started by spcecst2) then it's quite reasonable to assume some  might endure to EOT. During tx,  HR outlined a possible role for riba in eliminating stealth virions, however, as I noted  recent data argues pretty convincingly IMHO against riba's role as an HCV mutagen.  Post tx, SVR only results if the  host's immune system is able to eliminate/contain   residual  virus. It's  a safe bet the body's endogenous interferon expression pathways have gotten very little use while on tx simply  because of the abundance of injected ifn, so coaxing the virus-detection-and-ifn-expression paths back to life seems like a reasonable strategy, sort of like wearing crutches to support an atrophied leg after the cast comes off.

[jmjm530]

There are lots of interesting things to contemplate here, but I really don't have a position.

Moving on just a little -- some interesting work by Dr. Gerond Lake-Bakaar in NYC who as of at least a couple of years ago was involved in something called "pulse therapy".

The idea basically here was to treat with SOC and test viral load weekly from week 1. Once UND the treatment was stopped but weekly testing continued. As soon as the viral load became detectible, treatment was started again. That cycle would be one "pulse". In theory, this cycle was continued for "x" number of pulses until the virus remained gone for six months, i.e. SVR. That ended treatment.

Last I heard, the best he got was 4 months of UND after 2 or 3 pulses, which to me at least is hopeful in that it seemed he was "almost" there because it's quite uncommon for relapse at the 4 month post treatment mark.

No idea if his experiments have gone further, but I suppose one might be updated if an email correspondence was established.  Last I heard he was looking for that missing "ingredient" that might make that last pulse work. Perhaps it might be Alinia. Or one of the vaccine's in trial, which I believe was his hope then.  Or even Telaprevir. Or perhaps it could be a taper of Peg (or some sort of low dose mainteance between the first few pulses) as opposed to stopping the drugs altogether between each pulse.  

The part of pulse therapy that interested me is that in theory it could greatly reduce treatment time and only expose an individual patient to as many pulses as they require to SVR. And no doubt, the "rest" periods inbetween pulses would be a big relief to most, especially in terms of hemoglobin recovery. But again, last I heard no one has SVRd on Pulse therapy. Too bad not more out-of-the-box work like this isn't going on.

-- Jim

[jmjm530]

I should probably add that I considered tapering off the Peg at the end of treatment but in the end decided not to "rock the boat".

What I mean is that I was RVR, then UND throughout treatment via senstive TMA, and therefore was given a chance of SVR anywhere between 70 - 95 per cent depending on which hepatologist I talked to. (I figured I was around 80-85 per cent).

So, at that point, it was kinda like stay with what is known (stopping the peg and riba cold) and play the known projected odds,  versus try something not trialed. Nothing scientific here, just my thought pattern.

On the other hand, had I responded late, and had my projected odds been a lot less, I  no doubt would have been more open to various things, including tapering off --  as there is a certain logic to it as you and HR have detailed -- especially the idea of a temporary  immune drop immed after Peg is stopped. Wonder if there is any way to test for such a drop in the immune system?  In any event, you would think someone might trial tapering versus not at some point.

-- Jim

[willing]

I suspect with each pulse you would quickly eliminate the virus most suscepible to  ifn-induced cytolytic clearance leaving a "selected"  residual population (which implicitly  has to be less reproductively fit or the ifn would have yielded no VL decline). When the pulse ended, the selected, ifn-hardy,  virus would have a chance to mutate back towards a more reproductively fit genome and VL would rise past UND. Over time you might succeed in breeding virus that was both ifn resistant and reproductively fit!

I think this would be an interesting experiment  if you could obtain sequences at each mini-relapse; comparison of the re-emergent  sequences might tell you which viral genes are most susceptible to ifn since these newly-minted genes presumably would have more variation than the rest of the genome.  However, I'm not sure breeding this super-strain would be a win for  the patient...

[jmjm530]

Certainly make sense, but I saw it more as like "interval training" for the immune system, as opposed to LSD (long slow distance) to use athletic training terms.

I know it apparently is only one case, but does seem interesting that he got as far as 4 months UND post tx drugs with one patient, which could of course support your theory of strong re-emergence where least expected.

I still like the theory and certainly examining/comparing re-emergent sequences (can they do that?) might help map out the next step.

But playing devil's advocate, given the fact that so many here have SVRd on the second or third time around, is "interferon resistance" a real concern with such a broad immune booster (interferon) -- as opposed more targeting PI's where mutation might be more of a concern.

- Jim