Significance of increasing levels of minimal residual disease

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This is a recent publication of an abstract published in the Journal of Clinical

Oncology, Vol 27, No 22 (August 1), 2009: pp. 3659-3663

© 2009 American Society of Clinical Oncology.

Corresponding author: Hagop Kantarjian, MD, Department of Leukemia, The

University of Texas, M. D. Cancer Center, 1515 Holcombe Blvd, Unit 428,

Houston, TX 77030; e-mail: hkantarj@... .

" Purpose: The aim of this study was to evaluate the clinical relevance of

increases in quantitative polymerase chain reaction (QPCR) levels in patients

with chronic myelogenous leukemia (CML) who are in complete cytogenetic response

(CGCR) on therapy. Patients with Philadelphia chromosome (Ph)–positive CML

receiving tyrosine kinase inhibitors (TKIs) are frequently monitored for

response by QPCR studies for minimal molecular disease. The clinical

significance of increasing levels of QPCR in patients in CGCR is uncertain.

Patients and Methods: One hundred sixteen patients in durable CGCR, and on

imatinib therapy for at least 18 months, had increases in QPCR levels

(documented at least twice consecutively) as defined by literature reports.

These were further analyzed by the achievement of major molecular response (MMR)

defined as QPCR 0.05%, as well as by the degree of increase in QPCR.

Results: Only 11 (9.5%) of 116 patients with increases in QPCR had CML

progression; 10 of them were among 44 patients (23%) who either lost a MMR or

never had a MMR, and had more than 1 log increase of QPCR.

Conclusion: Most patients with increases in QPCR remain in CGCR. Patients who

lose a MMR or never achieve a MMR, and have more than 1 log increase of QPCR,

should be monitored more closely, and may be evaluated for mutations of BCR-ABL

kinase domain and considered for investigational therapeutic interventions.

Supported by the Betty Research Grant, and grant No. CML PO1 2 CA

49639-20 from the National Institutes of Health.

FYI

Lottie Duthu