Interesting article. http://www.haematolo...7.abstract?etoc
If I were recently diagnosed, I would like to have an OCT-1 level done to see if I have a low level, and therefore need 800 mg. of Gleevec vs. 400 mg., or another TKI. Frank
Posted 04 June 2012 - 05:30 PM
It is not so simple, since Oct1 (aka hOct1) expression changes significantly during periods of higher leukemic cell count. At diagnosis the Oct1 levels are usually below what would be normally expected. So the results could be easily misinterpreted.
Posted 04 June 2012 - 06:39 PM
I asked about if I could have a test for this when I was first diagnosed and was told "don't worry about it, we'll just put you on 400mg and see how you respond". Not sure if that was a money issue or she just didn't think it was necessary to find out.
I didn't know that it oct1 expression changes though, that is interesting to know.
Diagnosed 9 June 2011, Glivec 400mg June 2011-July 2017, Tasigna 600mg July 2017-present (switched due to intolerable side effects, and desire for future cessation attempt).
Commenced monthly testing when MR4.0 lost during 2012.
2017: <0.01, <0.01, 0.005 (200mg Glivec, Adelaide) <0.01, 0.001 (new test sensitivity)
2016: <0.01, <0.01, PCRU, 0.002 (Adelaide)
2015: <0.01, <0.01, <0.01, 0.013
2014: PCRU, <0.01, <0.01, <0.01, <0.01
2013: 0.01, 0.014, 0.016, 0.026, 0.041, <0.01, <0.01
2012: <0.01, <0.01, 0.013, 0.032, 0.021
2011: 38.00, 12.00, 0.14
Posted 04 June 2012 - 09:31 PM
I doubt that any labs do an hOct1 test. It is sort of a lab rat test for research purposes.
Posted 05 June 2012 - 06:54 PM
I sent the abstract to Dr. Hughes, and recieved this reply. Frank
"Thanks for sending me this abstract from ASCO. It contains a lot of data but I find it hard to follow. I think it confirms our findings that OCT-1 mRNA is higher in neutrophils and lower in immature cells. Our main focus is the measure of OCT-1 activity rather than mRNA level and the correlation here is quite weak. We suspect our functional assay may be measuring more than just the level of expression of this influx protein. Our test is performed on mononuclear cells so as well as reflecting the leukaemia-specific influx activity it also reflects the mix of cells present in the blood at diagnosis.
The Haematologica paper is the first convincing evidence we have produced that patients with low OCT-1 activity will achieve better responses with high dose imatinib, and that patients with high OCT-1 activity will probably do just as well on standard or high dose imatinib. This should be valuable for clinicians. However our challenge is to make this assay broadly available. It is a functional assay that requires carbon 14 labelled imatinib - not a practical assay for routine testing. We are currently working on developing a more robust assay that can be widely disseminated and could then become part of the diagnostic work up. The test must be performed on leukaemic cells so it can only be performed at diagnosis. So in answer to your last question we could only do an OCT-1 assay in a patient who has fresh or frozen blood cells from diagnosis. As far as I am aware no other labs have developed this assay yet.
Professor Timothy Hughes
Head, Dept of Haematology,
SA Pathology, RAH site
Office 08 82223330
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