3 replies to this topic

[jlegakis]

Hi all!  I havebeen on 800 mg. Tasigna now for 1 year and I reached FISH NEG > after 3 mos. and have stayed there, BUT my PCR results do not match! 28%, then 11%, 13% and finally, 16% in that order. I am stable and, perhaps, at a plateau, BUT could my lab be inaccurate or high? Interestingly I had a PCR done at Dr. Druker's lab and registered 4.74% right after the 13% I listed here a few mos. ago! So, there is definitely a discrepancy! Any suggestions? 

[thatguy]

Bosulif, ponatinib? You're long overdue to be below 1%, remembering your history.

[scuba]

FISH negative is the most important milestone. It is the single marker that tells you survival odds. Patients who achieve FISH /negative (CCyR) have the same survival profile as PCRU. 

 

However - getting to PCRU is desirable to test cessation and worth pursuing (drug switch). Keep in mind what PCR and FISH are measuring. FISH is measuring actual CML cells visible under the microscope. When FISH drops to zero you have very few CML cells left IN COMPARISON to normal blood. When PCR is measured, it is measuring CML cell activity ( bcr-abl protein synthesis). It is very possible for one CML cell to produce much more bcr-abl protein than another CML cell. Same number of cells, but one patient has more PCR than another. Also - PCR measurement is not that precise. Two tests from the same lab on the same sample can be as much as one log difference in readings.

 

Some labs are better than others in testing procedures. I would value Druker's lab over most any other.

[gerry]

Thanks scuba - after 7 years I finally get the difference in the tests.