Given expression of two BCR-ABL1 transcript, I would prefer to monitor by P210 if monitoring facility for both transcript is not available, as P210 is likely to by the transcript of primary clone. However, considering that p190 is coming from a subclone, I would prefer to do hematological monitoring by CBC more frequently, may be monthly to detect any probable hematological relapse from that subclone.

I agree with Delphine and I think it is important to put this into perspective. A large part if not majority of the world does not have access to accurate and timely pcr monitoring. Those of us with a lot of resources at our fingertips often forget this. Monitor what can be done readily and that should support the patients. Perhaps in the future, all of us will have access to all drugs and all technology.

Usually e19a2 constitute a minority and most CML MRD is made of Major transcripts.
Monitoring should thus be done using major transcript tools.

The P190 transcripts derive from alternative splicing and therefore you must follow the predominant e13 or e14 BCR/ABL type of transcript.

What are the levels of each transcript type? It is often common for cases of p210 disease to have very low levels of the p190 transcript at diagnosis, and this is believed to be a splicing event with no impact on prognosis.

"Both p210 and p190" in which %? Generally, p210 is predominant (1-2% of all CP patients may exhibit this association). However, there are data supporting a worse prognosis for patients bearing the association. Generally, those who progress do so in the early days.

I understand you do qualitative RT QPCR at diagnosis due to financial pressures of many patients, but it’s important to follow-up with quantitative monitoring of the highest burden. It is important to know at diagnosis if p190 is a small fraction or the highest burden. Generally, it is a small fraction and disappears rapidly. If prevalent, this notion has relevant prognostic features with p190 bearing a worse prognostic meaning vs p210.

To be practical, in terms of management, there is no strong data in favour of second gen TKIs vs imatinib. Monitoring is as per p210 only patient.