{"product_id":"new-expert-framework-defines-lines-of-therapy-for-blood-cancers","title":"New Expert Framework Defines \"Lines of Therapy\" for Blood Cancers","description":"\u003cp\u003eAn international committee of blood cancer experts has published a new framework that standardizes how \"lines of therapy\" are defined for leukemias, lymphomas, and multiple myeloma. The framework defines a line of therapy as one coherent treatment episode aimed at controlling the disease, which can include several phases such as induction, consolidation, and maintenance. A new line begins only when the disease progresses, relapses, or fails to respond, or when a drug from a completely different therapeutic class is added to deepen the response. The goal is to make treatment reporting consistent across studies and registries so that research and patient care can improve.\u003c\/p\u003e\n\n\u003ch1\u003eNew Expert Framework Defines \"Lines of Therapy\" for Blood Cancers\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003ca href=\"#background\"\u003eBackground: Why This Research Matters\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#current-state\"\u003eThe Current State of the Art\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#methodology\"\u003eHow the Framework Was Developed\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#definition\"\u003eWhat Is a Line of Therapy?\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#phases\"\u003eUnderstanding Treatment Phases\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#criteria\"\u003eThe Seven Rules for Assigning a Line of Therapy\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#examples\"\u003eDisease-Specific Examples\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#implications\"\u003eWhat This Means for Patients\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#limitations\"\u003eLimitations of the Framework\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations and Next Steps\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eA line of therapy is one coherent treatment episode aimed at controlling the disease, which can include several phases such as induction, consolidation, and maintenance.\u003c\/li\u003e\n\u003cli\u003eA new line begins only when the disease progresses, relapses, or fails to respond, or when a drug from a completely different therapeutic class is added to deepen the response.\u003c\/li\u003e\n\u003cli\u003eStandardized definitions help ensure that patients are appropriately classified for clinical trial participation and that registry data are consistent and meaningful.\u003c\/li\u003e\n\u003cli\u003eDose reductions or schedule changes for side effect management do not create a new line of therapy, but substituting an agent with a different mechanism of action does.\u003c\/li\u003e\n\u003cli\u003eBridging therapy before CAR-T or transplant is not counted as a separate line of therapy; the entire sequence is considered a single line.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eBackground: Why This Research Matters\u003c\/h2\u003e\n\n\u003cp\u003eTreatments for blood cancers (hematological malignancies) have changed dramatically in recent years. Targeted therapies, immunotherapy, and cellular therapies have transformed the way these diseases are treated. Patients with diseases that once progressed rapidly and had poor outcomes now often live much longer.\u003c\/p\u003e\n\n\u003cp\u003eMany patients now receive multiple sequential lines of therapy over a prolonged disease course. This progress has created a new problem. There is no consistent way to define and count \"lines of therapy\" (LoT) across different studies, registries, and clinical practices.\u003c\/p\u003e\n\n\u003cp\u003eThe European Society for Blood and Marrow Transplantation (EBMT) identified this problem as a major barrier. Without a standard definition, clinicians and data managers rely on their own interpretations. This leads to wide variability and potential misclassification of treatments.\u003c\/p\u003e\n\n\u003cp\u003eInconsistent definitions can hinder routine clinical care, registry-based research, and eligibility for clinical trials. Establishing uniformity is therefore a critical step toward better research and better evidence-based decision-making in precision hematology.\u003c\/p\u003e\n\n\u003cp\u003eThe challenge is well illustrated by the experience in multiple myeloma, a blood cancer characterized by prolonged survival and inevitable exposure to multiple sequential therapies. In 2015, Rajkumar and colleagues proposed guidelines for determining the number of prior lines of therapy in multiple myeloma.\u003c\/p\u003e\n\n\u003cp\u003eThose myeloma-specific guidelines represented a major step toward standardization. They have since been widely adopted in clinical trials and regulatory contexts. However, they also highlighted broader challenges that extend across all blood cancers.\u003c\/p\u003e\n\n\u003cp\u003eTreatment strategies increasingly incorporate complex combinations, multiple sequential phases of treatment, and novel modalities including cellular and immune-based therapies. Definitions based solely on regimen changes may fail to capture important information. These definitions may miss therapeutic intent, the biological significance of disease control or failure, and the continuity of planned treatment strategies.\u003c\/p\u003e\n\n\u003cp\u003eThis article presents a contemporary framework for determining lines of therapy in a consistent manner across blood cancers in 2026 and beyond.\u003c\/p\u003e\n\n\u003ch2 id=\"current-state\"\u003eThe Current State of the Art\u003c\/h2\u003e\n\n\u003cp\u003eThe current definition in the EBMT registry states that a line of treatment covers all cycles of the same drugs or regimen. The same drugs or regimen are administered during the same period, for the same reason, and within the same disease status of the patient.\u003c\/p\u003e\n\n\u003cp\u003eWithin this increasingly complex therapeutic landscape, the EBMT identified the need to further standardize the definition of lines of therapy across blood cancers. By formulating consensus-based criteria, the EBMT aims to harmonize data collection, improve the clarity of treatment reporting, and support the integration of emerging therapies into routine practice.\u003c\/p\u003e\n\n\u003cp\u003eSubstantial variation currently exists in how lines of therapy are defined and counted across studies and registries. In the absence of standardized guidelines, clinicians and investigators often rely on center-specific and individual interpretations. This leads to marked variability and potential misclassification.\u003c\/p\u003e\n\n\u003cp\u003eThe questions addressed by this framework include:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eWhat defines a line of therapy in blood cancers, and why is a standardized definition crucial for clinical practice and research?\u003c\/li\u003e\n\u003cli\u003eHow have targeted, immune, and cellular therapies redefined traditional approaches to lines of therapy?\u003c\/li\u003e\n\u003cli\u003eHow does variability in classification across studies, registries, and clinical practice impact patient care and research?\u003c\/li\u003e\n\u003cli\u003eWhich principles should be used to define a line of therapy?\u003c\/li\u003e\n\u003cli\u003eWhat are the most recent published guidelines for different blood cancers?\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"methodology\"\u003eHow the Framework Was Developed\u003c\/h2\u003e\n\n\u003cp\u003eThe framework was developed following the EBMT Practice Harmonisation and Guidelines Committee methodology. A panel of hematology and cell therapy experts from the EBMT was convened to address the need for standardized definitions.\u003c\/p\u003e\n\n\u003cp\u003eThe panel included the chairs of five EBMT working parties:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eThe Cellular Therapy and Immunobiology Working Party (CTIWP)\u003c\/li\u003e\n\u003cli\u003eThe Lymphoma Working Party (LWP)\u003c\/li\u003e\n\u003cli\u003eThe Pediatric Diseases Working Party (PDWP)\u003c\/li\u003e\n\u003cli\u003eThe Acute Leukemia Working Party (ALWP)\u003c\/li\u003e\n\u003cli\u003eThe Chronic Malignancies Working Party (CMWP)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThe scope of blood diseases and disease-specific recommendations was discussed during three dedicated teleconferences in autumn 2025. These discussions were consolidated in a one-day, in-person workshop held in October 2025.\u003c\/p\u003e\n\n\u003cp\u003eRecommendations were iteratively developed based on expert consensus, clinical experience, literature review, and analysis of EBMT registry data. Disease-specific examples were generated for acute leukemia, lymphomas, and multiple myeloma. Drafts were circulated electronically and refined through multiple rounds of review by all coauthors.\u003c\/p\u003e\n\n\u003ch2 id=\"definition\"\u003eWhat Is a Line of Therapy?\u003c\/h2\u003e\n\n\u003cp\u003eA line of therapy is defined as a coherent therapeutic episode initiated to achieve, re-achieve, or maintain disease control. It is characterized by a dominant intent, which may be curative, disease-controlling, or palliative.\u003c\/p\u003e\n\n\u003cp\u003eA line of therapy is composed of one or more sequential systemic treatment phases. These phases are administered without the occurrence of disease progression, treatment failure, or major toxicity requiring a change in treatment.\u003c\/p\u003e\n\n\u003cp\u003eThis definition is anchored in two conceptual pillars:\u003c\/p\u003e\n\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eTherapeutic intent:\u003c\/strong\u003e The clinical objective guiding treatment initiation determines the categorization of a line of therapy.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisease progression:\u003c\/strong\u003e Sequential treatment phases administered in the absence of disease progression or treatment failure constitute a single line of therapy. The initiation of new therapy following clinically confirmed progression defines the start of a subsequent line of therapy.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003eA line of therapy is considered ended when there is disease progression, relapse, or treatment failure. Treatment failure due to persistence of disease is defined as the continued presence of detectable disease following a planned therapy. This indicates that the treatment did not achieve adequate disease control or eradication. In such cases, the new treatment initiated is defined as salvage therapy and marks the beginning of a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003eTherefore, the total number of therapeutic lines prior to cellular therapy is calculated as first-line treatment plus the number of salvage therapies received. Cellular therapy includes allogeneic stem cell transplant, autologous stem cell transplant, or CAR-T cell therapy.\u003c\/p\u003e\n\n\u003ch2 id=\"phases\"\u003eUnderstanding Treatment Phases\u003c\/h2\u003e\n\n\u003cp\u003eSystemic treatment is commonly structured into distinct but sequentially connected phases. Each phase is defined by its intent and its temporal relationship to disease response or progression.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eInduction\u003c\/strong\u003e constitutes the initial therapeutic phase. Induction aims to achieve remission through the eradication or substantial reduction of malignant cells.\u003c\/p\u003e\n\n\u003cp\u003eOnce remission is achieved, \u003cstrong\u003econsolidation therapy\u003c\/strong\u003e follows. Consolidation aims to eliminate residual disease and deepen the response. It often employs intensified chemotherapy, targeted agents, and hematopoietic cell transplantation (HCT) or cellular therapies.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMaintenance therapy\u003c\/strong\u003e is subsequently administered to sustain remission and delay relapse. Maintenance typically uses lower-intensity or continuous regimens designed to suppress residual cancer cell activity.\u003c\/p\u003e\n\n\u003cp\u003eOther therapeutic phases include holding or bridging therapy. \u003cstrong\u003eHolding therapy\u003c\/strong\u003e encompasses any systemic treatment delivered before a planned definitive therapeutic intervention, such as chimeric antigen receptor T-cell therapy (CAR-T).\u003c\/p\u003e\n\n\u003cp\u003eHolding therapies are defined as those administered between the identification of the need for CAR-T and leukapheresis (the collection of a patient's immune cells). \u003cstrong\u003eBridging therapies\u003c\/strong\u003e are those delivered between leukapheresis and subsequent CAR-T infusion.\u003c\/p\u003e\n\n\u003cp\u003eThese treatments are intended to maintain or achieve remission, prevent disease regrowth, or stabilize the patient during logistical or medical delays. Such delays precede the definitive therapy of CAR-T cell collection, manufacturing, and reinfusion.\u003c\/p\u003e\n\n\u003cp\u003eIn contrast, \u003cstrong\u003esalvage therapy\u003c\/strong\u003e refers to the administration of a new regimen following relapse, progression, or treatment failure. The objective of salvage therapy is to reinduce remission, prolong disease control, or provide palliation.\u003c\/p\u003e\n\n\u003ch2 id=\"criteria\"\u003eThe Seven Rules for Assigning a Line of Therapy\u003c\/h2\u003e\n\n\u003cp\u003eThe framework provides seven specific rules with clarifications and disease-specific examples for acute leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma, and multiple myeloma.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRule 1: Induction, consolidation, and maintenance therapies are considered components of a single, continuous line of therapy when delivered without intervening progression and with a consistent therapeutic intent.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eAll planned treatment phases constituting parts of a unified strategy remain within the same line of therapy. This applies provided no measurable residual disease (MRD)-defined or overt progression occurs. MRD refers to the presence of a small number of cancer cells that remain in the body during or after treatment.\u003c\/p\u003e\n\n\u003cp\u003eFor example, in acute myeloid leukemia (AML), induction chemotherapy followed by consolidation up to four cycles is considered a single line of therapy. Consolidation includes allogeneic or autologous stem cell transplant, and a subsequent maintenance strategy is also considered part of the same single line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRule 2: A new line of therapy must be assigned when progression, relapse, or primary refractory disease is documented.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eLoss of disease control indicates the end of the preceding therapeutic episode. This loss may be detected clinically, morphologically, radiologically, or by validated MRD assays. It includes not only overt progression or relapse after response, but also failure to achieve disease control at the end of treatment, defined as primary refractory disease.\u003c\/p\u003e\n\n\u003cp\u003eIn all such cases, initiation of a new therapeutic strategy constitutes a new line of therapy. For example, in diffuse large B-cell lymphoma (DLBCL), persistent disease at the end of treatment is termed primary refractory disease. CAR-T therapy or salvage therapy, such as R-DHAP followed by autologous stem cell transplant, is considered second-line therapy despite the absence of progression.\u003c\/p\u003e\n\n\u003cp\u003eIn multiple myeloma, a patient who progresses on post-transplant maintenance with daratumumab and lenalidomide and whose treatment is switched to a carfilzomib-based regimen is starting a second line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRule 3: The addition of therapeutic agents that are pre-planned and incorporated in advance into the initial treatment regimen does not constitute a new line of therapy. This is true even when these agents belong to different drug classes.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eSome contemporary regimens incorporate targeted or immunotherapeutic agents as part of a predefined treatment strategy. Although these agents may have different mechanisms of action, they remain part of a single therapeutic episode when they are prospectively pre-planned and specified in the initial treatment protocol.\u003c\/p\u003e\n\n\u003cp\u003eThe treatment plan is prospectively defined. The treatment plan is initiated before evidence of disease progression. The treatment plan is delivered within the same intent to achieve remission. The entire regimen constitutes one single line of therapy. This applies regardless of the number or diversity of agents included.\u003c\/p\u003e\n\n\u003cp\u003eFor example, in AML, gemtuzumab ozogamicin, venetoclax, or other targeted therapies may be added upfront to induction and consolidation chemotherapy as part of the standard induction regimen. These agents are all considered part of the first-line therapy and therefore do not constitute a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003eIn frontline B-acute lymphoblastic leukemia (B-ALL) treatment, blinatumomab given early as a planned MRD-directed consolidation step remains part of the initial treatment strategy. Blinatumomab given early as a planned MRD-directed consolidation step does not represent a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003eAn insufficient response leading to a planned treatment escalation is considered part of the same line of therapy, provided there is no disease progression. For example, in Hodgkin lymphoma, a patient treated with ABVD who does not achieve a metabolic complete response on interim PET imaging may be escalated to BEACOPP or BrECADD. This escalation is part of the same line of therapy. Similarly, radiotherapy for residual disease is considered part of the same line of therapy when it is pre-planned.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRule 4: The introduction of an agent from a different therapeutic class, added with the purpose of improving or deepening response, initiates a new line of therapy.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThe addition of a pharmacologically distinct agent reflects a substantive modification of the therapeutic strategy. Such an agent is introduced with the explicit aim of augmenting response. The aim may be converting partial response to complete remission. The aim may be eliminating MRD. The aim may be achieving deeper disease control. The treatment plan transitions to a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003eFor example, in acute lymphoblastic leukemia (ALL), a patient treated with multi-agent chemotherapy who achieves morphological remission but remains MRD-positive is considered to have initiated a new line of therapy. This is because the patient subsequently receives blinatumomab with the intent of eradicating MRD. The introduction of a bispecific T-cell engager represents a change in therapeutic class and reflects a new therapeutic strategy rather than continuation of the initial regimen.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRule 5: The modification of dose, schedule, or timing does not change the line of therapy.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eAdjustments to dosage, administration schedule, or treatment timing do not constitute a new line of therapy. This includes delays, interruptions, or spacing of cycles, whether performed for toxicity management, organ dysfunction, intolerance, patient frailty, or intercurrent illness.\u003c\/p\u003e\n\n\u003cp\u003eSimilarly, partial omission or early discontinuation of specific components of a regimen remains within the same line of therapy. This applies provided that the overall therapeutic intent and fundamental regimen structure are preserved. Such modifications are recognized components of routine clinical practice aimed at optimizing safety, tolerability, and feasibility without altering the underlying therapeutic strategy.\u003c\/p\u003e\n\n\u003cp\u003eFor example, in Hodgkin lymphoma, a patient is treated with ABVD. An interim PET scan after two cycles (PET2) demonstrates complete metabolic response in the patient. Bleomycin may be omitted from subsequent cycles. The patient continues with AVD. This planned omission to reduce toxicity while preserving the original therapeutic intent does not constitute a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRule 6: The substitution of an agent with an agent of a different spectrum constitutes a new line of therapy.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eIf a therapeutic agent is discontinued and replaced by another agent with a different pharmacological spectrum or mechanism of action, this change represents a substantive modification of the therapeutic strategy. Therefore, it defines the initiation of a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003eThis applies regardless of whether the substitution is prompted by toxicity, intolerance, or lack of efficacy. The key factor is that the change reflects a shift in the dominant treatment approach rather than a modification of dose or schedule within the same regimen.\u003c\/p\u003e\n\n\u003cp\u003eFor example, a patient with Philadelphia chromosome-positive ALL receiving dasatinib may develop a clinically significant pleural effusion, necessitating discontinuation of the drug. Therapy is subsequently switched to ponatinib, a third-generation tyrosine kinase inhibitor (TKI) with a broader inhibitory spectrum and activity against resistant disease-associated ABL mutations. This substitution constitutes a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003eIn multiple myeloma, a patient develops severe hepatitis on an anti-B-cell maturation antigen (BCMA) bispecific antibody. The patient then switches to an alternative anti-GPRC5D bispecific antibody. This constitutes a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRule 7: Holding and bridging therapy before cellular therapy remains within the same line of therapy.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eBridging therapy administered prior to lymphodepletion and infusion of cellular therapy (such as CAR-T cells) does not constitute a new therapeutic episode. Bridging therapy does not alter the dominant therapeutic intent, which remains focused on proceeding to definitive cellular therapy.\u003c\/p\u003e\n\n\u003cp\u003eBridging treatment is therefore considered a functional component of the same line of therapy during short intervals. These intervals are required for CAR-T manufacturing, recovery from toxicity, completion of eligibility assessments, or optimization of organ function.\u003c\/p\u003e\n\n\u003cp\u003eIn this framework, the entire sequence of eventual holding and bridging therapy followed by CAR-T infusion constitutes a single line of therapy. This applies even though multiple agents or regimens may be used within that interval. The line of therapy is defined by the overarching therapeutic strategy (delivery of cellular therapy), not by the number of interim regimens administered.\u003c\/p\u003e\n\n\u003cp\u003eWhile bridging therapy and CAR-T together comprise a single line of therapy, the line number assigned to CAR-T reflects the number of prior completed lines of therapy. Thus, CAR-T may be described as being administered after two prior lines of therapy, while still constituting the current line of therapy together with any associated bridging therapy.\u003c\/p\u003e\n\n\u003ch2 id=\"examples\"\u003eDisease-Specific Examples\u003c\/h2\u003e\n\n\u003cp\u003eThe framework provides detailed examples for each disease type to illustrate how the rules apply in practice.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAcute Myeloid Leukemia (AML) — One Line of Therapy:\u003c\/strong\u003e A patient receives intensive chemotherapy for induction, achieves complete remission, receives consolidation chemotherapy for up to four cycles, undergoes allogeneic stem cell transplant, and then receives maintenance therapy. All of these phases are considered a single line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAcute Myeloid Leukemia (AML) — Two Lines of Therapy:\u003c\/strong\u003e A patient receives intensive chemotherapy for induction, achieves complete remission, receives consolidation for up to four cycles, undergoes stem cell transplant, and receives hypomethylating agent (HMA) maintenance. The patient then relapses and receives salvage therapy with HMA plus venetoclax or targeted therapy. The salvage treatment constitutes a second line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAcute Lymphoblastic Leukemia (ALL) — Two Lines of Therapy:\u003c\/strong\u003e A patient receives a tyrosine kinase inhibitor (TKI) plus steroids for induction, achieves complete remission, receives consolidation with low-intensity chemotherapy, and receives maintenance TKI. The patient then relapses and receives an alternative TKI plus blinatumomab or immunotherapy plus intrathecal therapy. The treatment after relapse constitutes a second line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePhiladelphia Chromosome-Positive ALL — TKI Toxicity:\u003c\/strong\u003e A patient receives TKI plus steroids for induction, develops TKI-related toxicity, and is switched to an alternative TKI plus chemotherapy for consolidation, followed by maintenance plus intrathecal therapy. The switch to an alternative TKI constitutes a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDiffuse Large B-Cell Lymphoma (DLBCL) — Two Lines of Therapy:\u003c\/strong\u003e A patient receives R-CHOP for induction. PET imaging after two cycles is positive, so the patient receives two additional cycles. PET imaging after four cycles remains positive, so the patient receives salvage R-DHAP, achieves complete or partial response, and undergoes autologous stem cell transplant. The salvage treatment constitutes a second line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDiffuse Large B-Cell Lymphoma — CAR-T as Second Line:\u003c\/strong\u003e A patient receives R-CHOP, achieves complete remission, then relapses. The patient receives bridging therapy, followed by lymphodepletion and CAR-T infusion. Both the bridging therapy and CAR-T infusion are considered part of the same second line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHodgkin Lymphoma — One Line of Therapy (Escalation):\u003c\/strong\u003e A patient receives ABVD for induction. PET imaging after two cycles is positive, so treatment is escalated to BEACOPP or BrECADD. Residual disease is treated with radiotherapy. All of these treatments are considered one line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHodgkin Lymphoma — One Line of Therapy (De-escalation):\u003c\/strong\u003e A patient receives ABVD for induction. PET imaging after two cycles shows complete metabolic response, so treatment continues with AVD (bleomycin omitted). Alternatively, a patient receives BEACOPP for induction, achieves complete metabolic response on PET2, and continues with ABVD. Both scenarios represent one line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMultiple Myeloma — Two Lines of Therapy:\u003c\/strong\u003e A patient receives daratumumab plus RVd for induction, undergoes autologous stem cell transplant with high-dose melphalan, receives daratumumab plus lenalidomide maintenance, then relapses and receives KCd salvage therapy. The salvage treatment constitutes a second line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMultiple Myeloma — Treatment Toxicity:\u003c\/strong\u003e A patient receives teclistamab for induction but develops toxicity, so treatment is switched to talquetamab. This substitution constitutes a new line of therapy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMultiple Myeloma — Holding and Bridging Before CAR-T:\u003c\/strong\u003e A patient relapses and receives KDd (carfilzomib, daratumumab, and dexamethasone) as the next line of therapy. Following lymphocyte collection, the patient receives talquetamab as bridging therapy prior to conditioning and cilta-cel infusion. The talquetamab does not constitute a new line of therapy.\u003c\/p\u003e\n\n\u003ch2 id=\"implications\"\u003eWhat This Means for Patients\u003c\/h2\u003e\n\n\u003cp\u003eThis framework has several important implications for patients with blood cancers.\u003c\/p\u003e\n\n\u003cp\u003eFirst, consistent definitions mean that clinical trials will be easier to compare. When every study uses the same rules for counting lines of therapy, researchers can more accurately determine which treatments work best and for whom.\u003c\/p\u003e\n\n\u003cp\u003eSecond, registry data will become more reliable. Transplant and cellular therapy registries collect information from many centers. Standardized definitions ensure that this information is consistent and meaningful.\u003c\/p\u003e\n\n\u003cp\u003eThird, patients may benefit from clearer communication about their treatment history. When your care team describes how many lines of therapy you have received, that number will have a consistent meaning across different hospitals and health systems.\u003c\/p\u003e\n\n\u003cp\u003eFourth, eligibility for clinical trials often depends on the number of prior lines of therapy. Standardized definitions help ensure that patients are appropriately classified for trial participation.\u003c\/p\u003e\n\n\u003cp\u003eThe framework also clarifies several situations that commonly cause confusion:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eAdding a new drug to an existing regimen does not always mean starting a new line of therapy, if that drug was part of the original plan.\u003c\/li\u003e\n\u003cli\u003eSwitching from one drug to another within the same class may or may not constitute a new line, depending on the reason for the switch.\u003c\/li\u003e\n\u003cli\u003eBridging therapy before CAR-T or transplant is not counted as a separate line of therapy.\u003c\/li\u003e\n\u003cli\u003eDose reductions or schedule changes for side effect management do not create a new line of therapy.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"limitations\"\u003eLimitations of the Framework\u003c\/h2\u003e\n\n\u003cp\u003eThis framework represents expert consensus rather than validation through prospective clinical studies. The recommendations were developed based on clinical experience, literature review, and analysis of registry data, but they have not yet been tested in a prospective manner.\u003c\/p\u003e\n\n\u003cp\u003eThe framework was developed specifically for acute leukemias, lymphomas, and multiple myeloma. Additional harmonization efforts are warranted to validate this framework across a broader range of blood diseases.\u003c\/p\u003e\n\n\u003cp\u003eThe authors acknowledge that prospective evaluation within the EBMT registry will be needed. This evaluation will support assessment of data quality, consistency, standardization, and real-world applicability.\u003c\/p\u003e\n\n\u003cp\u003eAs new therapies continue to emerge, the framework may require updates. The authors note that the therapeutic landscape continues to evolve rapidly, and definitions may need refinement over time.\u003c\/p\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations and Next Steps\u003c\/h2\u003e\n\n\u003cp\u003eThe EBMT plans several steps to implement this framework and improve the quality of its registry.\u003c\/p\u003e\n\n\u003col\u003e\n\u003cli\u003eA fully updated data collection manual will be distributed to centers. This manual will reflect the revised definitions and procedures for reporting treatment lines.\u003c\/li\u003e\n\u003cli\u003eEducational webinars for clinicians and data managers will be delivered. These webinars will help ensure consistent application of the new definitions.\u003c\/li\u003e\n\u003cli\u003eProspective evaluation within the EBMT registry will assess data quality, consistency, standardization, and real-world applicability.\u003c\/li\u003e\n\u003cli\u003eAdditional harmonization efforts will validate the framework across a broader range of blood diseases.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003eThe authors believe that the framework proposed in this article could represent a useful step toward future harmonization of line of therapy reporting across transplant and cell therapy registries.\u003c\/p\u003e\n\n\u003cp\u003eFor patients, the key takeaway is that the medical community is working to make treatment reporting more consistent and reliable. This should ultimately support better research and better evidence-based decision-making in precision hematology.\u003c\/p\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eWhat is a 'line of therapy' for blood cancers?\u003c\/h3\u003e\n\u003cp\u003eA line of therapy is one coherent treatment episode aimed at controlling the disease. It can include several phases, such as induction, consolidation, and maintenance. A new line begins only when the disease progresses, relapses, or fails to respond, or when a drug from a completely different therapeutic class is added to deepen the response.\u003c\/p\u003e\n\u003ch3\u003eWhy does the number of prior lines of therapy matter for clinical trial eligibility?\u003c\/h3\u003e\n\u003cp\u003eEligibility for clinical trials often depends on the number of prior lines of therapy. Standardized definitions help ensure that patients are appropriately classified for trial participation. When every study uses the same rules for counting lines of therapy, researchers can more accurately determine which treatments work and for whom.\u003c\/p\u003e\n\u003ch3\u003eIf I switch drugs because of side effects, does that count as a new line of therapy?\u003c\/h3\u003e\n\u003cp\u003eIt depends on the reason for the switch. Dose reductions or schedule changes for side effect management do not create a new line of therapy. However, substituting an agent with one that has a different pharmacological spectrum or mechanism of action does constitute a new line of therapy, even if the switch is prompted by toxicity or intolerance.\u003c\/p\u003e\n\u003ch3\u003eDoes bridging therapy before CAR-T count as a separate line of therapy?\u003c\/h3\u003e\n\u003cp\u003eNo. Bridging therapy administered before lymphodepletion and infusion of cellular therapy, such as CAR-T cells, does not constitute a new therapeutic episode. The entire sequence of holding and bridging therapy followed by CAR-T infusion is considered a single line of therapy, even though multiple agents or regimens may be used within that interval.\u003c\/p\u003e\n\u003ch3\u003eWhat does it mean if my disease is primary refractory?\u003c\/h3\u003e\n\u003cp\u003ePrimary refractory disease means the continued presence of detectable disease following a planned therapy, indicating that the treatment did not achieve adequate disease control or eradication. In such cases, the new treatment initiated is defined as salvage therapy and marks the beginning of a new line of therapy.\u003c\/p\u003e\n\u003ch3\u003eHow will this framework affect my care and communication with my treatment team?\u003c\/h3\u003e\n\u003cp\u003ePatients may benefit from clearer communication about their treatment history. When your care team describes how many lines of therapy you have received, that number will have a consistent meaning across different hospitals and health systems. Registry data will also become more reliable, as standardized definitions ensure that information collected from many centers is consistent and meaningful.\u003c\/p\u003e\n\u003ch3\u003eIs this framework validated and will it be updated?\u003c\/h3\u003e\n\u003cp\u003eThis framework represents expert consensus rather than validation through prospective clinical studies. It was developed specifically for acute leukemias, lymphomas, and multiple myeloma. Prospective evaluation within a registry will be needed to assess data quality, consistency, standardization, and real-world applicability. As new therapies continue to emerge, the framework may require updates.\u003c\/p\u003e\n\u003ch3\u003eWhen should a patient with a blood cancer seek a second opinion about how many lines of therapy they have received?\u003c\/h3\u003e\n\u003cp\u003eA second opinion is worth considering when the number of prior lines of therapy affects your options, such as eligibility for a clinical trial or cellular therapy. Counting can be unclear: adding a drug that was part of the original plan, dose or schedule changes for side effects, and holding or bridging therapy before CAR-T all stay within the same line, while progression, relapse, primary refractory disease, or substituting an agent with a different spectrum starts a new one. An independent review can confirm how your treatment history is classified. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eOriginal article title:\u003c\/strong\u003e Defining lines of therapy in haematological malignancies: a proposed systematic and comprehensive framework from the EBMT Practice Harmonisation and Guidelines Committee.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Criscimanna A, Galimard JE, Sánchez-Ortega I, Hayden PJ, Garderet L, Sureda A, Ciceri F, McLornan DP, Kałwak K, Risitano AM, Onida F, Yakoub-Agha I, Bazarbachi A, Ruggeri A.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublication:\u003c\/strong\u003e Bone Marrow Transplantation (2026) 61:977–982\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDOI:\u003c\/strong\u003e https:\/\/doi.org\/10.1038\/s41409-026-02914-0\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublished online:\u003c\/strong\u003e 3 June 2026\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e This patient-friendly article is based on peer-reviewed research. The original article was published as an open-access perspective in Bone Marrow Transplantation. No generative AI tools were used in the preparation of the original manuscript.\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47828053262492,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/diagnosticdetectives.com\/da\/products\/new-expert-framework-defines-lines-of-therapy-for-blood-cancers","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}