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.

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.

A key clinical nuance in CLL is that not all prognostic markers are static. The IGHV mutation status remains unchanged, requiring a one-time test. However, chromosomal abnormalities like deletion 17p can evolve, necessitating re-evaluation at each relapse to guide subsequent therapy choices and adapt the treatment strategy.

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.

In the era of potent targeted therapies for Philadelphia chromosome-positive B-ALL, the most critical factor for deciding on a consolidative allogeneic stem cell transplant is persistent minimal residual disease (MRD). This response-based metric has become more important than baseline mutational status for upfront risk stratification and treatment planning.

The zanubrutinib-venetoclax arm of the SEQUOIA trial, while technically 'MRD-guided', had such strict criteria for stopping treatment (e.g., two bone marrow biopsies) that very few patients qualified. This design flaw meant most patients effectively received continuous zanubrutinib after the initial combination phase.

Despite the appeal of stopping treatment, a key insight from clinical practice is that patients' most critical question remains which therapy offers the longest period of remission, often overriding factors like treatment duration and oral-only options.

The CLL17 trial revealed a counterintuitive finding: unfit patients had worse outcomes on continuous ibrutinib, likely due to toxicity-related discontinuations. The logistically harder venetoclax-obinutuzumab fixed-duration regimen produced equal efficacy in both fit and unfit patients, making it a better choice for the less fit.