about 1 in 526 In the United States, chronic myeloid leukemia (CML) will be diagnosed this year, but most of these people will have a normal life expectancy due to tyrosine kinase inhibitors (TKIs).
When it was approved in 2001, the first TKI drug transformed CML from a death sentence to Life expectancy is about six years A livable chronic disease. But lifelong TKI treatment has a cost: it imposes a heavy financial burden on patients and payers, and its side effects can challenge hospitals and compromise patients’ quality of life.
Recently, researchers discovered that Droplet Digital PCR (ddPCR), a highly sensitive DNA quantification technique, can reliably determine when a patient can safely stop treatment.
TKI: Savior and Burden
TKIs reverse the physiological imbalances that promote the growth of cancer cells in the blood.an abnormal fusion gene called BCR-ABL1 Produces an overactive tyrosine kinase protein that causes overgrowth of several blood cell types, including red and white blood cells. When these cancer cells crowd out healthy cells, they cause a range of systemic symptoms, including anemia, infection and abnormal blood clotting.
TKIs counteract this effect by inhibiting kinases, thereby inhibiting tumor growth. While TKIs have high therapeutic value, they are not always 100% effective, putting patients at risk of relapse. To be on the safe side, oncologists tend to keep patients on TKI therapy for longer than might be necessary, sometimes for the rest of their lives.
Treating cancer and preventing recurrence is a top priority for oncologists. But patients also need protection from the burden of treatment, including side effects that can affect quality of life in a number of ways.For example, patients report that serious side effectsespecially after years of continuous treatment.
Patients may feel fatigued more easily, making it difficult to exercise or exercise. This treatment can lead to diarrhea, forcing patients to think twice about participating in limited bathroom activities. Because of the increased risk of miscarriage, women using TKIs are advised not to become pregnant.
Ongoing side effects can lead to emotional tension and depression.Furthermore, ongoing TKI treatments are expensive, costing nearly $150,000 per patient per year. This high price tag places financial stress on uninsured patients and payers.
Overall, TKIs have been incredibly successful in prolonging the lives of CML patients. Nonetheless, patients, providers and payers can all benefit from discontinuing TKI therapy when it is safe to do so.
Measuring CML at the molecular level
quantify BCR-ABL1 mRNA levels in the blood of CML patients allow oncologists to calculate molecular response (MR), an indicator of treatment efficacy.After three months of treatment, the oncologist use MR to determine if their patients need to change their treatment regimen. After finding an effective treatment, physicians continuously monitor MR to assess disease burden and determine treatment goals.
MR can be measured using one of several techniques, including PCR, quantitative PCR (qPCR), droplet digital PCR (ddPCR), and next-generation sequencing (NGS).The oncologist’s goal is to detect — or, in the case of qPCR and ddPCR, quantify — cycle BCR-ABL1 Transcript.Currently, there are Four FDA approved or approved BCR-ABL1 diagnosisall based on qPCR or ddPCR technology.
High BCR-ABL1 Levels indicate active disease, while undetectable levels suggest the patient may be in remission.because BCR-ABL1 level down Slowly, many patients must use TKIs for several years to achieve deep molecular responses—more than 4 log reductions BCR-ABL1 level (according to the international standard MR4).
If patients remained in this state for two years, they achieved a sustained deep molecular response (sDMR). Current data suggest that patients who have been on TKI therapy for at least three years and are in sDMR can attempt to stop TKI therapy, a stage known as treatment-free remission (TFR).
Find the best molecular diagnostics
Many of the problems with oncologists and patients surrounding TKI discontinuation stem from uncertainty in the techniques used to measure MR.it may be BCR-ABL1 Levels may drop low enough to evade detection by the gold standard diagnostic technique, qPCR, while remaining high enough to cause relapse. These remaining cancer cells are called minimal residual disease (MRD).
Current data suggest that 50% to 60% of patients with sDMR by qPCR still have MRD and are likely to relapse. a study Examining treatment discontinuation in 142 CML patients found that ddPCR could detect more cases of MRD than qPCR.This indicates that ddPCR is more accurate and sensitive in detection and monitoring BCR-ABL1 levels compared to qPCR. The authors suggest that ddPCR technology could make sDMR easier to confirm and therefore easier to identify patients who are eligible to discontinue treatment.
another study Several factors predicting recurrence were examined, including BCR-ABL1 Levels measured using ddPCR techniques. In addition to the treatment time, BCR-ABL1 Levels after treatment cessation were the strongest predictor of relapse.In fact, the ddPCR technique detected BCR-ABL1 Transcripts from 75 patients with negative qPCR.
Overall, these data suggest that there is still hope for sDMR patients who wish to discontinue treatment.more sensitive BCR-ABL 1 The testbed, the more confident the physician is that the patient will have a successful TFR. With this deeper level of certainty that negative results are accurate, oncologists can stop treatment for their patients, sparing them years or even decades of debilitating side effects.
More information and options for patients and oncologists
The decision to stop cancer treatment is a complex and emotional one between patients, their families and their doctors. Some CML patients may be relieved to stop treatment, while others may be hesitant to stop an effective treatment regimen.
Out of an abundance of caution, oncologists may choose to keep their patients on TKIs, even at the expense of the patient’s overall health and potential financial burden. However, increasing data suggest that there is a reasonably safe route to discontinuation of TKI therapy in patients undergoing sDMR.
Hopefully, these data will help start more conversations about how oncologists can help patients enjoy the extra years TKIs give them by stopping treatment when appropriate.
Photo: aldomurillo, Getty Images
