Navigating Challenges in Monitoring Chronic Myeloid Leukemia with Multiple BCR-ABL1 Transcripts

Quantitative PCR-based strategies are typically effective for monitoring BCR-ABL1 transcript levels in chronic myeloid leukemia (CML). Additionally, some patients treated with tyrosine kinase inhibitors can experience long-term treatment-free remission after discontinuation of the inhibitor. However, this outcome hinges on effectively monitoring the patient's response to therapy. We present a patient with CML and multiple BCR-ABL1 transcripts, including a rare isoform that lacks qPCR standardization. We describe unexpected discrepancies in transcript quantification, further having an impact on clinical decision-making regarding duration of treatment. To better inform clinical practice, we suggest monitoring patients at the same testing facility to better track transcript trend.