Regular monitoring of patients with chronic myeloid leukemia (CML) who are receiving treatment with a tyrosine kinase inhibitor (TKI) is essential, explains B. Douglas Smith, MD. Traditionally, patients have been monitored using peripheral blood polymerase chain reaction (PCR) testing every 3 months. It is important to continue monitoring levels, even if the patient has normal blood counts and is physically doing well, Smith notes.

A national survey conducted by researchers at MD Anderson examined prescribing and monitoring of patients with CML taking TKIs, explains Elias Jabbour, MD. The surprising results showed that approximately 15% of patients had never had a PCR test and that there was a lack of regular monitoring. Actively monitoring patients is important, since regularly tracking this information can cue clinicians into early signs of potential resistance or change in response.

The SIMPLICITY trial (NCT01244750) is a large observational study spanning 7 countries that also examined the issue of patient monitoring, notes Stuart L. Goldberg, MD. According to this study, only ~40% of patients worldwide were undergoing PCR testing 3 to 4 times during the critical first year; in addition, 15% of patients had no PCR or cytogenetic testing during the first year.

Understandably, once a patient has a consistent major molecular response (MMR), monitoring can be conducted less frequently; for example, reduced from every 3 months to every 6 months. However, Goldberg raises the concern that poor management and monitoring leads to higher costs from progressions, and affects survival.

Some of the barriers to cytogenetic testing include costs, not believing in guidelines, and difficulty following recommendations. But the important question is, “What is the cost of NOT doing the tests?” Smith stresses that proper testing can help to determine if patients are in a stable state and thus can possibly discontinue the drug. He explains that conducting a test for a few hundred dollars and ultimately being able to discontinue use of a $100,000-a-year drug makes the cost of performing these tests seem significantly less substantial.