MRD Status Guides First-Line Treatment Duration in Haematologic Malignancies

The landscape of first-line treatment for haematologic malignancies has evolved, offering both continuous and fixed-duration therapeutic strategies. Continuous therapies, while often effective in maintaining disease control, carry the burden of prolonged toxicity, potential for cumulative adverse events, and impact on patient quality of life. Conversely, fixed-duration therapies offer a defined treatment period, potentially reducing long-term side effects and improving patient convenience, but risk earlier relapse if not adequately potent. The EHA 2026 presentations underscored the clinical dilemma of selecting the most appropriate strategy for individual patients, particularly in the absence of clear biomarkers to guide treatment cessation or intensification.¹

Measurable Residual Disease (MRD), defined as the presence of a small number of cancer cells that remain in the body after treatment, has emerged as a powerful prognostic factor across various haematologic malignancies, including chronic lymphocytic leukaemia (CLL), multiple myeloma (MM), and acute myeloid leukaemia (AML).² Achieving MRD negativity after initial therapy is consistently associated with superior progression-free survival (PFS) and overall survival (OS).³ This robust correlation positions MRD as a potential tool to individualise treatment duration, moving beyond empirical approaches.⁴

MRD-Guided Treatment Strategies

Discussions at EHA 2026 focused on how MRD assessment can inform first-line treatment decisions. For conditions like CLL, fixed-duration regimens such as venetoclax-obinutuzumab have demonstrated deep and durable responses, with a significant proportion of patients achieving undetectable MRD (uMRD) in peripheral blood and bone marrow.⁵ Trials evaluating these regimens have shown that patients achieving uMRD after a defined treatment course often experience prolonged PFS, suggesting that further continuous therapy may not be necessary for all patients.⁵ Conversely, patients who remain MRD-positive after initial fixed-duration therapy may benefit from treatment intensification or a switch to a continuous regimen.⁶

In multiple myeloma, the role of MRD is similarly evolving. While continuous lenalidomide maintenance remains a standard after autologous stem cell transplantation (ASCT), studies are exploring whether MRD negativity could identify patients for whom maintenance therapy could be de-escalated or even stopped.⁷ The challenge lies in the sensitivity and standardisation of MRD detection methods, with next-generation sequencing (NGS) and next-generation flow cytometry (NGF) offering high sensitivity, detecting one malignant cell among 10^-5 or 10^-6 normal cells.⁸ The clinical utility of these highly sensitive methods in guiding treatment cessation outside of clinical trials is still under investigation, particularly regarding the long-term outcomes and the risk of late relapse.⁹

For AML, MRD assessment post-induction and consolidation is a critical prognostic factor. Achieving MRD negativity is associated with a lower risk of relapse and improved survival.¹⁰ While the primary focus in AML has been on guiding post-remission therapy, such as allogeneic stem cell transplantation, the concept of MRD-driven treatment duration in non-transplant eligible patients is gaining traction.¹¹ The EHA 2026 sessions highlighted ongoing trials designed to prospectively evaluate MRD-guided treatment duration, aiming to establish definitive evidence for de-escalation or intensification based on MRD status.¹²

The primary limitation in broadly implementing MRD-guided treatment duration is the lack of universally standardised assays and cut-offs across different diseases and treatment settings. Variability in sample collection, processing, and detection methodologies can lead to inconsistent results, complicating clinical decision-making.¹³ Furthermore, the predictive value of MRD negativity for long-term outcomes, particularly in novel therapeutic combinations, requires further maturation of clinical trial data. The EHA discussions emphasised the need for harmonisation efforts and the development of robust, validated assays to ensure reliable and reproducible MRD results in routine clinical practice.¹⁴ Future research will focus on integrating MRD assessment into adaptive trial designs to prospectively validate MRD-driven treatment strategies and establish clear guidelines for their application.