When diffuse large B-cell lymphoma does not respond to initial treatment or returns after a period of remission, patients face a challenging situation that requires specialized care and careful treatment planning. Understanding the available options—from intensive chemotherapy to advanced cellular therapies—can help patients and their families navigate this difficult time with greater confidence.

When Lymphoma Stops Responding: Understanding the Challenge

Diffuse large B-cell lymphoma is an aggressive type of cancer that affects the body’s immune system, specifically white blood cells called B-lymphocytes. While many people respond well to initial treatment, approximately 30 to 40 percent of patients will either not respond to the first therapy or experience a return of the disease after achieving remission.^[1][2] This creates a medical situation that requires careful assessment and a different treatment approach than what was used initially.

The terms used to describe this situation have specific meanings that help doctors plan the next steps. Relapsed disease means that the lymphoma has come back after a period where it seemed to be gone or under control, known as remission. This return can happen months or even years after successful initial treatment.^[1] On the other hand, refractory disease describes a situation where the lymphoma never really responded to treatment in the first place, meaning the cancer cells continued to grow despite therapy, or any improvement was very brief.^[1]

The goal of treating relapsed or refractory diffuse large B-cell lymphoma is complex and depends heavily on individual circumstances. For some patients, particularly those who are younger and in good overall health, the aim remains achieving a cure through intensive treatments. For others, the focus shifts toward controlling symptoms, slowing disease progression, and maintaining the best possible quality of life. Medical teams consider many factors when developing a treatment plan, including how soon the disease returned after initial treatment, the patient’s overall physical condition, age, other health problems, and personal preferences about treatment intensity.^[1][2]

The prognosis for patients with relapsed or refractory disease has historically been challenging. A landmark study called SCHOLAR-1 examined outcomes in 636 patients with refractory diffuse large B-cell lymphoma and found that only about 26 percent responded to their next line of treatment, with just 7 percent achieving complete disappearance of detectable disease. The median overall survival was only 6.3 months for these patients.^[2] However, these sobering statistics come from data collected before several important new treatments became available. Recent years have brought significant advances in therapy options, offering renewed hope for patients facing this diagnosis.^[4]

Standard Treatment Approaches for Disease That Returns

When diffuse large B-cell lymphoma relapses or proves refractory, the standard approach for many patients involves intensive chemotherapy followed by stem cell transplantation. Stem cells are immature blood cells that can develop into all types of blood cells the body needs. In most cases, patients receive an autologous transplant, which means doctors collect the patient’s own stem cells before administering very high doses of chemotherapy. After this intensive chemotherapy destroys both cancer cells and the bone marrow’s ability to produce new blood cells, the previously collected stem cells are returned to the patient’s body, where they travel to the bone marrow and begin producing healthy blood cells again.^[1][5]

Less commonly, some patients may undergo an allogeneic transplant, where stem cells come from a donor rather than from the patient. This approach carries different risks and benefits compared to autologous transplantation and is typically reserved for specific situations.^[1]

Before transplantation can occur, patients typically receive what doctors call salvage chemotherapy regimens. These are combinations of chemotherapy drugs designed to shrink the lymphoma and determine whether the disease will respond to treatment. Several different combination regimens are commonly used, and research has not clearly shown one to be superior to others.^[11] The response to this salvage chemotherapy is critically important because it helps predict whether stem cell transplantation will be successful.

Common salvage chemotherapy combinations include ICE, which stands for ifosfamide, carboplatin, and etoposide. Another frequently used regimen is DHAP, consisting of dexamethasone, cisplatin, and cytarabine. Some centers use gemcitabine-based therapies or other combinations.^[1][5] These are powerful medications that work by interfering with cancer cells’ ability to grow and divide. Because they also affect healthy cells, particularly those that divide rapidly, patients experience side effects such as increased risk of infection due to lowered white blood cell counts, fatigue from reduced red blood cells, bleeding risks from decreased platelets, nausea, vomiting, hair loss, and mouth sores.

For patients whose disease responds well to salvage chemotherapy, proceeding to high-dose chemotherapy followed by autologous stem cell transplantation offers the best chance for long-term disease control and potential cure in the relapsed setting. Historically, this approach has cured approximately 20 percent of relapsed patients, though this percentage has improved with newer treatment approaches.^[4]

However, more than 80 percent of relapsed or refractory patients historically either did not respond sufficiently to salvage chemotherapy or were not healthy enough to undergo the intensive transplant procedure. This left a large group of patients with very limited options and poor outcomes.^[4] Recognition of this unmet need has driven the development of multiple new treatment approaches in recent years.

Newer Approved Medications for Relapsed or Refractory Disease

Beyond traditional salvage chemotherapy, several newer drugs have been approved for treating relapsed or refractory diffuse large B-cell lymphoma. These medications work through different mechanisms than standard chemotherapy and offer options for patients who cannot undergo transplantation or whose disease has not responded to other treatments.

One category of newer treatments includes combinations of targeted antibodies with chemotherapy. The combination of bendamustine and rituximab represents one such approach. Bendamustine is a chemotherapy drug with a unique chemical structure that combines properties of different drug classes, while rituximab is a monoclonal antibody that specifically targets a protein called CD20 found on the surface of B-lymphocytes, including lymphoma cells.^[1][5] When rituximab attaches to CD20, it marks the cancer cells for destruction by the immune system.

Another combination pairs lenalidomide with rituximab. Lenalidomide is an immunomodulatory agent, meaning it modifies how the immune system functions, helping it recognize and attack cancer cells more effectively while also directly affecting the cancer cells’ ability to survive and grow.^[1][5] This combination has shown activity in relapsed or refractory patients, particularly those who are not candidates for intensive transplant procedures.

Several individual targeted agents have also received approval for this setting. Polatuzumab vedotin-piiq, marketed as Polivy, represents an antibody-drug conjugate. This innovative approach combines an antibody that targets CD79b, another protein found on B-cells, with a chemotherapy drug attached to it. The antibody acts like a guided missile, delivering the chemotherapy directly to lymphoma cells while sparing more normal cells from exposure.^[1][5] When combined with bendamustine and rituximab, polatuzumab vedotin has shown improved outcomes compared to bendamustine and rituximab alone.

Selinexor, sold under the brand name Xpovio, works through a completely different mechanism. This oral medication blocks a protein called exportin 1, which normally helps move certain other proteins out of the cell nucleus. By blocking this export process, selinexor causes tumor suppressor proteins to accumulate in the nucleus where they can trigger cancer cell death.^[1][5] Common side effects include nausea, fatigue, decreased appetite, weight loss, and low blood cell counts.

Tafasitamab-cxix, marketed as Monjuvi, is another monoclonal antibody that targets CD19, a different protein on B-cells. It is used in combination with lenalidomide for patients who are not candidates for stem cell transplantation.^[1][5] This combination works by both directly killing lymphoma cells and enhancing the immune system’s natural ability to recognize and eliminate cancer cells.

For patients with a specific subtype of diffuse large B-cell lymphoma called primary mediastinal large B-cell lymphoma, pembrolizumab (Keytruda) offers another option. This drug is a checkpoint inhibitor, a type of immunotherapy that works by releasing brakes on the immune system. Normally, cancer cells can hide from immune attack by expressing proteins that tell immune cells to leave them alone. Pembrolizumab blocks these “don’t attack me” signals, allowing immune cells to recognize and destroy the lymphoma.^[1][5]

Advanced Immunotherapy: CAR T-Cell Therapy

One of the most significant advances in treating relapsed or refractory diffuse large B-cell lymphoma has been the development and approval of chimeric antigen receptor T-cell therapy, commonly called CAR T-cell therapy. This approach represents a fundamentally different way of fighting cancer compared to traditional treatments. Instead of using drugs or radiation from outside the body to kill cancer cells, CAR T-cell therapy engineers the patient’s own immune cells to become powerful cancer fighters.^[1][5]

The process begins with collecting T-cells, a type of white blood cell that normally helps fight infections, from the patient’s blood through a procedure similar to blood donation called apheresis. These cells are then sent to a specialized laboratory where scientists genetically modify them to express a chimeric antigen receptor on their surface. This artificial receptor is designed to recognize and bind to CD19, a protein abundantly present on B-cell lymphomas. Once the cells have been modified and multiplied to large numbers in the laboratory, they are frozen and shipped back to the treatment center.^[4]

Before receiving the modified cells back, patients typically undergo a brief course of chemotherapy to reduce the number of normal lymphocytes in their body, creating space and a favorable environment for the CAR T-cells to expand. The CAR T-cells are then infused back into the patient through a vein, similar to a blood transfusion. Once in the body, these engineered cells can recognize lymphoma cells through the CD19 protein, attach to them, and release substances that kill the cancer cells. Additionally, the CAR T-cells multiply inside the patient’s body, creating an army of cancer fighters.^[4]

Three CAR T-cell products have received approval for treating relapsed or refractory diffuse large B-cell lymphoma: axicabtagene ciloleucel (Yescarta), lisocabtagene maraleucel (Breyanzi), and tisagenlecleucel (Kymriah).^[1][5] Initial approval came in 2017 for use in patients who had already failed at least two prior lines of therapy. Clinical trials demonstrated impressive response rates, with about 82 percent of patients showing some response and 58 percent achieving complete disappearance of detectable disease with axicabtagene ciloleucel. Importantly, five-year follow-up data showed that more than 40 percent of patients remained alive, demonstrating the potential for long-term disease control and possible cure even in heavily pretreated patients.^[4]

More recently, in 2021, the FDA approved CAR T-cell therapy with either axicabtagene ciloleucel or lisocabtagene maraleucel for use earlier in the disease course, specifically for patients with primary refractory disease or disease that relapses within 12 months of initial treatment. Two major phase III clinical trials, called ZUMA-7 and TRANSFORM, demonstrated that CAR T-cell therapy was superior to standard salvage chemotherapy followed by stem cell transplantation in this high-risk group.^[4][6] This represents a major shift in how doctors approach treatment for patients whose lymphoma either never responded well initially or came back quickly.

CAR T-cell therapy is not without risks and side effects. The most concerning complications are cytokine release syndrome and neurological toxicities. Cytokine release syndrome occurs when the activated CAR T-cells release large amounts of immune signaling molecules called cytokines, causing symptoms ranging from fever and low blood pressure to, in severe cases, organ dysfunction requiring intensive care. Neurological side effects can include confusion, difficulty speaking, seizures, or altered consciousness. Most of these complications occur within the first few weeks after infusion and are typically reversible, though they require close monitoring and sometimes treatment with medications that dampen the immune response. Patients receiving CAR T-cell therapy are monitored closely in specialized centers with experience managing these complications.

Bispecific Antibodies: A Newer Form of Immunotherapy

The most recent additions to the treatment landscape for relapsed or refractory diffuse large B-cell lymphoma are bispecific antibodies. These innovative medications represent another form of immunotherapy that works by bringing T-cells into close contact with lymphoma cells. Unlike CAR T-cell therapy, which requires collecting cells from the patient and manufacturing a personalized product, bispecific antibodies are “off-the-shelf” medications that can be administered without delay.^[4]

Bispecific antibodies work through their unique structure: one end of the molecule binds to CD3, a protein found on T-cells, while the other end binds to CD20 or CD19 on lymphoma cells. By physically linking T-cells to cancer cells, these medications activate the T-cells to kill the lymphoma cells. This creates a temporary but powerful immune attack against the cancer.

Two bispecific antibodies have been approved for relapsed or refractory diffuse large B-cell lymphoma: epcoritamab-bysp (Epkinly) and glofitamab-gxbm (Columvi).^[1][5] These medications are typically given by injection under the skin or infusion into a vein on a regular schedule. Like CAR T-cell therapy, they can cause cytokine release syndrome, particularly with the first few doses, so patients are monitored closely during initial treatments. However, the risk of severe side effects generally decreases with subsequent doses as the tumor burden decreases.

Early results with bispecific antibodies have shown promising response rates in heavily pretreated patients, including some who had previously received CAR T-cell therapy. These medications provide an important option for patients whose disease has progressed through multiple other therapies or who are not candidates for CAR T-cell therapy.

Most common treatment methods

• Stem Cell Transplantation
  • High-dose chemotherapy followed by autologous stem cell transplant uses the patient’s own stem cells collected before intensive treatment
  • Allogeneic transplant uses donor stem cells and is less commonly performed
  • Typically preceded by salvage chemotherapy to reduce disease burden
  • Offers potential for cure in patients whose disease responds to salvage therapy
• Salvage Chemotherapy Combinations
  • ICE regimen: ifosfamide, carboplatin, and etoposide
  • DHAP regimen: dexamethasone, cisplatin, and cytarabine
  • Gemcitabine-based combinations
  • Bendamustine plus rituximab
  • Used to shrink disease before transplant or as treatment for transplant-ineligible patients
• CAR T-Cell Therapy
  • Axicabtagene ciloleucel (Yescarta): approved for relapsed/refractory disease and early relapse
  • Lisocabtagene maraleucel (Breyanzi): approved for relapsed/refractory disease and early relapse
  • Tisagenlecleucel (Kymriah): approved for relapsed/refractory disease
  • Genetically engineers patient’s T-cells to recognize and kill lymphoma cells
  • Has shown potential for long-term remission even in heavily pretreated patients
• Targeted Antibody Therapies
  • Polatuzumab vedotin-piiq (Polivy): antibody-drug conjugate targeting CD79b
  • Tafasitamab-cxix (Monjuvi): monoclonal antibody targeting CD19, used with lenalidomide
  • Epcoritamab-bysp (Epkinly): bispecific antibody linking T-cells to lymphoma cells
  • Glofitamab-gxbm (Columvi): bispecific antibody with similar mechanism
  • Work by directing immune attack against cancer cells or delivering chemotherapy directly to them
• Immunomodulatory and Targeted Agents
  • Lenalidomide (Revlimid) plus rituximab: modifies immune function and directly affects cancer cells
  • Selinexor (Xpovio): blocks protein export from cell nucleus
  • Pembrolizumab (Keytruda): checkpoint inhibitor for primary mediastinal large B-cell lymphoma subtype
  • Offer alternatives for patients not eligible for intensive therapy

Factors That Influence Treatment Decisions

Choosing the right treatment for relapsed or refractory diffuse large B-cell lymphoma involves considering multiple factors beyond just the disease itself. One of the most important considerations is timing: when did the disease relapse? Patients whose lymphoma relapses within 12 months of initial treatment or who never achieved a good response to first-line therapy have a particularly poor prognosis with standard salvage approaches and are now generally recommended to receive CAR T-cell therapy as their next treatment rather than salvage chemotherapy followed by stem cell transplantation.^[4][6]

For patients who relapse more than 12 months after completing initial treatment, the approach may be more individualized. These patients have historically had better outcomes with salvage chemotherapy and stem cell transplantation compared to those who relapse early. Current practice often involves starting with salvage chemotherapy to assess disease responsiveness. Patients who achieve a good response may proceed to stem cell transplantation, while those whose disease proves resistant to salvage therapy would be considered for CAR T-cell therapy or other novel approaches.^[4]

A patient’s overall fitness and health status profoundly influence treatment options. Intensive chemotherapy followed by stem cell transplantation or CAR T-cell therapy requires patients to be in reasonably good physical condition to tolerate the treatments and their side effects. Doctors assess what they call “fitness for intensive therapy” by considering factors such as age, other medical conditions (heart disease, lung problems, kidney function), ability to perform daily activities, and nutritional status. Patients who are not fit enough for these intensive approaches may be better served by less toxic targeted therapies or immunomodulatory agents that can provide disease control with more manageable side effects.^[4]

The biological characteristics of the lymphoma also matter. Some subtypes of diffuse large B-cell lymphoma may respond differently to various treatments. For example, primary mediastinal large B-cell lymphoma, which typically occurs in younger patients and involves the chest, may respond particularly well to pembrolizumab.^[1] Advanced testing of tumor samples can sometimes identify specific genetic or molecular features that might make certain therapies more or less likely to work.

Geographic location and access to specialized centers also play a practical role. CAR T-cell therapy is only available at designated centers with specific expertise and infrastructure to manage the therapy and its complications. Similarly, some clinical trials testing the newest therapies may only be available at certain academic medical centers. Patients and their families often need to travel for treatment and plan for extended stays near the treatment center for monitoring.

Emerging Therapies and Clinical Trial Opportunities

Beyond the treatments already approved, numerous promising therapies are being tested in clinical trials for patients with relapsed or refractory diffuse large B-cell lymphoma. These studies represent hope for patients whose disease has not responded to available treatments or who experience relapse after multiple therapies. Participation in well-designed clinical trials not only provides access to potentially effective new treatments but also contributes to advancing medical knowledge that will benefit future patients.

Clinical trials progress through defined phases that help researchers understand whether new treatments are safe and effective. Phase I trials primarily focus on determining the correct dose of a new medication and identifying side effects. These studies typically enroll small numbers of patients and involve careful dose escalation, starting with low doses and gradually increasing until the optimal balance between effectiveness and tolerability is found.

Phase II trials test whether a treatment shows enough promise of working against the cancer to warrant further study. These trials enroll more patients than Phase I studies and focus on measuring response rates—what percentage of patients experience shrinkage or disappearance of their lymphoma. Phase II trials also continue to monitor side effects and refine understanding of the dose and schedule.

Phase III trials represent the final step before a treatment can be approved by regulatory agencies. These large studies randomly assign patients to receive either the new treatment or the current standard treatment, allowing direct comparison to determine if the new approach is superior. The ZUMA-7 and TRANSFORM trials that led to expanded approval of CAR T-cell therapy were Phase III studies.^[4]

Several categories of experimental treatments are currently being investigated. Newer generations of CAR T-cell therapy are being developed to potentially work better or cause fewer side effects than current products. Some experimental CAR T-cells target different proteins on lymphoma cells besides CD19, which might help overcome resistance that can develop when lymphoma cells stop expressing CD19.

Additional bispecific antibodies with different designs or targeting different combinations of proteins are in testing. Some of these may have improved efficacy or reduced toxicity compared to currently approved bispecific antibodies. Researchers are also studying whether combining bispecific antibodies with other treatments might produce better results than either therapy alone.

A class of drugs called checkpoint inhibitors, which have revolutionized treatment of several other cancers, continues to be studied in diffuse large B-cell lymphoma. While pembrolizumab is approved for the primary mediastinal subtype, researchers are testing whether other checkpoint inhibitors or combinations might benefit broader groups of patients with relapsed disease.

Novel antibody-drug conjugates beyond polatuzumab vedotin are in development, linking antibodies that target different proteins on lymphoma cells with various chemotherapy or toxin payloads. The goal is to deliver cancer-killing substances directly to malignant cells while sparing normal tissues.

Small molecule drugs that interfere with specific pathways lymphoma cells need to survive are another active area of investigation. These include inhibitors of proteins involved in cell survival signaling, cell cycle regulation, and other processes that cancer cells depend on more heavily than normal cells.

Clinical trials are being conducted at cancer centers throughout the United States, Europe, and other regions. Eligibility criteria vary by study but typically consider factors such as how many prior treatments the patient has received, current overall health status, organ function, and specific characteristics of the lymphoma. Patients interested in clinical trial participation should discuss this with their oncology team, who can help identify appropriate studies. Many patients also find information through resources provided by patient advocacy organizations and through clinical trial databases.

Managing Treatment Side Effects and Quality of Life

All treatments for relapsed or refractory diffuse large B-cell lymphoma carry the potential for side effects, though the specific problems vary depending on the type of therapy. Understanding potential side effects and having plans to manage them helps patients maintain the best possible quality of life during treatment.

Traditional chemotherapy regimens affect rapidly dividing cells throughout the body, not just cancer cells. This leads to common side effects including reduced blood cell counts (increasing infection risk, causing fatigue, and affecting clotting), hair loss, nausea and vomiting, mouth sores, and fatigue. Modern supportive care medications can prevent or reduce many of these problems. Growth factors can help the bone marrow recover more quickly, reducing the duration of dangerously low blood counts. Anti-nausea medications have improved dramatically and can control nausea for most patients. Patients are educated about when to seek immediate medical attention, particularly for fever while blood counts are low, as infections can become serious quickly.

CAR T-cell therapy brings unique challenges related to immune system activation. Cytokine release syndrome can range from mild flu-like symptoms to severe organ dysfunction. Most cases occur within the first week after CAR T-cell infusion and respond to supportive care and, when needed, medications that dampen immune activation such as tocilizumab. Neurological side effects including confusion, tremors, difficulty speaking, or altered consciousness typically appear within the first few weeks and are usually reversible, though they require close monitoring. Because of these potential complications, patients receiving CAR T-cell therapy remain near the treatment center for several weeks after infusion for monitoring.

Bispecific antibodies can cause similar immune-related side effects, particularly cytokine release syndrome with initial doses. Treatment centers have developed strategies to reduce these risks, including giving the first dose or doses in an inpatient setting where patients can be closely monitored, using lower “step-up” doses initially, and premedicated patients with medications to blunt excessive immune activation.

Targeted therapies and immunomodulatory agents each have their own side effect profiles. Lenalidomide commonly causes low blood counts, fatigue, rash, and carries a risk of blood clots, so patients often take blood thinners preventatively. Selinexor frequently causes nausea, fatigue, and decreased appetite, which can be managed with anti-nausea medications and careful attention to nutrition. Checkpoint inhibitors can occasionally cause the immune system to attack normal organs, leading to inflammation of the lungs, intestines, liver, or other organs, though these effects are less common in lymphoma than in some other cancers where checkpoint inhibitors are used more widely.

Beyond physical side effects, dealing with relapsed or refractory cancer takes an emotional toll. Many patients experience anxiety, depression, fear about the future, and stress related to ongoing treatment and its impact on family and work life. Comprehensive cancer centers offer psychological support services including individual counseling, support groups, and sometimes psychiatric medication when appropriate. Some patients find benefit in complementary approaches such as meditation, yoga, acupuncture, or art therapy as adjuncts to medical treatment, though these should not replace proven cancer therapies.

Maintaining good nutrition becomes increasingly important but often more challenging during treatment for relapsed disease. Working with a dietitian who has expertise in oncology can help patients meet nutritional needs despite poor appetite or treatment side effects. Staying as physically active as possible, within the limits of safety given blood counts and energy levels, helps maintain strength and can improve mood and overall well-being.