Current fixed-duration CLL regimens are not MRD-guided, so the test result does not alter the treatment plan. While a negative result is prognostically favorable, its main clinical utility is to provide reassurance. A detectable result can cause unnecessary patient anxiety.

A key conceptual shift is viewing ctDNA not as a statistical risk marker, but as direct detection of molecular residual disease (MRD). This framing, similar to how a CT scan identifies metastases, explains its high positive predictive value and justifies its use in making critical treatment decisions.

Menin inhibitors achieve high rates of MRD-negative remissions. However, the median duration is very short (4-6 months), suggesting current MRD assays may not adequately capture residual disease and that "MRD negativity" is not a reliable predictor of long-term benefit for this drug class.

Although continuous BTK inhibitors have the most prospective data for high-risk CLL (17p/TP53 mutations), some highly motivated patients still opt for fixed-duration treatment. This requires a detailed conversation where clinicians must explain the trade-off: achieving a treatment-free period may come at the cost of needing second-line therapy sooner.

Experts predict that emerging cell-free DNA (ctDNA) tests for lymphoma will shift treatment from fixed durations to a response-adapted approach. Monitoring minimal residual disease via ctDNA will allow clinicians to tailor the length of therapy based on the quality of response.

Minimal Residual Disease (MRD) negativity is now recognized by regulators as a surrogate endpoint in oncology. Because it is considered 'reasonably likely to predict progression-free survival,' this shift allows drug developers to use MRD data to support accelerated approval pathways, expediting the availability of new therapies.

The UK FLAIR trial demonstrated for the first time that a time-limited regimen (ibrutinib-venetoclax), guided by MRD to a median duration of 27 months, achieved superior progression-free and overall survival compared to continuous ibrutinib therapy in frontline CLL.

If a patient's CLL therapy is stopped for another major health issue, such as a second cancer, clinicians should often observe them post-recovery rather than immediately restarting treatment. This approach is recommended even with detectable Minimal Residual Disease (MRD) to prioritize the patient's immune system recovery and overall health.

The FLAIR trial's MRD-guided protocol, while effective, created a paradox. Lower-risk, IGHV-mutated patients, who typically do well on shorter treatments, took longer to achieve undetectable MRD. This resulted in them receiving a longer duration of therapy than their higher-risk counterparts, representing likely overtreatment.