Bendamustine is safe and effective for lymphodepletion before tisagenlecleucel in patients with refractory or relapsed large B-cell lymphomas.

BACKGROUND: Anti-CD19 chimeric antigen receptor T-cell immunotherapy (CAR-T) is now a standard treatment of relapsed or refractory B-cell non-Hodgkin lymphomas; however, a significant portion of patients do not respond to CAR-T and/or experience toxicities. Lymphodepleting chemotherapy is a critical component of CAR-T that enhances CAR-T-cell engraftment, expansion, cytotoxicity, and persistence. We hypothesized that the lymphodepletion regimen might affect the safety and efficacy of CAR-T. PATIENTS AND METHODS: We compared the safety and efficacy of lymphodepletion using either fludarabine/cyclophosphamide (n = 42) or bendamustine (n = 90) before tisagenlecleucel in two cohorts of patients with relapsed or refractory large B-cell lymphomas treated consecutively at three academic institutions in the United States (University of Pennsylvania, n = 90; Oregon Health & Science University, n = 35) and Europe (University of Vienna, n = 7). Response was assessed using the Lugano 2014 criteria and toxicities were assessed by the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and, when possible, the American Society for Transplantation and Cellular Therapy (ASTCT) consensus grading. RESULTS: Fludarabine/cyclophosphamide led to more profound lymphocytopenia after tisagenlecleucel infusion compared with bendamustine, although the efficacy of tisagenlecleucel was similar between the two groups. We observed significant differences, however, in the frequency and severity of adverse events. In particular, patients treated with bendamustine had lower rates of cytokine release syndrome and neurotoxicity. In addition, higher rates of hematological toxicities were observed in patients receiving fludarabine/cyclophosphamide. Bendamustine-treated patients had higher nadir neutrophil counts, hemoglobin levels, and platelet counts, as well as a shorter time to blood count recovery, and received fewer platelet and red cell transfusions. Fewer episodes of infection, neutropenic fever, and post-infusion hospitalization were observed in the bendamustine cohort compared with patients receiving fludarabine/cyclophosphamide. CONCLUSIONS: Bendamustine for lymphodepletion before tisagenlecleucel has efficacy similar to fludarabine/cyclophosphamide with reduced toxicities, including cytokine release syndrome, neurotoxicity, infectious and hematological toxicities, as well as reduced hospital utilization.

Intensive graft-versus-host disease prophylaxis is required after unrelated-donor nonmyeloablative stem cell transplantation.

Nonmyeloablative stem cell transplantation (NST) harnesses the graft-versus-tumor effect while minimizing regimen-related toxicity, and can result in donor chimerism and remission. Acute graft-versus-host disease (GVHD) and infections are major complications after sibling NST. Toxicity of unrelated-donor (UD) NST and the most appropriate GVHD prophylaxis in this setting remain poorly defined. We describe 25 patients who received UD-NST conditioned with fludarabine and cyclophosphamide. The first six patients received cyclosporine (Cs) and mycophenolate mofetil (MMF) (n=5) or methotrexate (MTX) (n=1) as GVHD prophylaxis (group 1) and all developed grade III-IV acute GVHD. The next 19 patients received the same conditioning regimen with the addition of alemtuzumab, and all received Cs/MTX post-transplant. Engraftment and donor chimerism were achieved in all but one evaluable patient. In all, 15 patients died: five of six deaths in group 1 were attributable to acute GVHD, while deaths in group 2 were due to infection or progressive disease (P=0.05). The combination of Cs/MMF is inadequate GVHD prophylaxis for UD-NST. The use of Cs, MTX, and alemtuzumab eliminated severe acute GVHD; its impact on response merits further study.

Long-term event-free survivors after high-dose therapy and autologous stem-cell transplantation for low-grade follicular lymphoma.

Although follicular lymphoma (FL) is generally responsive to conventional-dose chemotherapy, improved survival in patients with this disease has been difficult to demonstrate. High-dose chemo/radiotherapy followed by autologous stem-cell transplantation (ASCT) can improve response rates, although its effects on survival remain controversial. Between 1990 and 2003, we transplanted 49 patients with low-grade FL at our institution. Twenty-two patients (45%) had undergone histologic transformation at the time of ASCT. In all, 44 patients (90%) had relapsed disease and five patients (10%) were resistant to chemotherapy at the time of transplantation. After ASCT, 30 patients (61%) were in complete remission (CR). The median overall survival (OS) has not been reached, while the median event-free survival (EFS) is 2.4 years. At a median follow-up of 5.5 years (longest 12.4 years), a plateau has been reached with 56% of patients remaining alive, and 35% event-free. ASCT was well tolerated except for two (4%) treatment-related deaths. In multivariable analysis, CR after ASCT and age less than 60 years are the best predictors of EFS and OS. ASCT is thus a safe therapeutic approach in FL, resulting in long-term EFS and OS for some patients, even with transformed disease.

Potential prolongation of PFS in mantle cell lymphoma after R-HyperCVAD: auto-SCT consolidation or rituximab maintenance.

We retrospectively analyzed 44 patients undergoing first-line treatment for mantle cell lymphoma with R-HyperCVAD, with or without rituximab (R) maintenance or auto-SCT. The primary study end point was PFS; secondary end point was overall survival.Median follow up for all patients was 3.3 years. Median age was 54 years, and 95% (n=42) were stage III or IV at diagnosis. In all, 17 patients underwent consolidative auto-SCT and 12 patients received R maintenance. The overall response rate was 95%, with 91% achieving complete response (CR). Median PFS for all patients was 3.5 years. Median PFS was 2.3 years for patients treated with R-HyperCVAD alone vs 3.9 years (P=0.02) with R-HyperCVAD+ R maintenance and 4.5 years (P=0.01) with R-HyperCVAD+ auto-SCT. For patients who did not achieve CR at interim staging, PFS for R-HyperCVAD alone was 1.4 years vs not reached for R-HyperCVAD+ consolidation (either R maintenance or auto-SCT) (P=0.02). PFS for patients with CR at interim staging was 3.3 years vs not reached (P=0.04) after consolidation. Our data suggest potential improvement in PFS when R-HyperCVAD is consolidated with either R maintenance or auto-SCT. This benefit appears particularly significant in those patients who do not achieve CR at interim restaging.

Allogeneic hematopoietic SCT for primary cutaneous T cell lymphomas.

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of non-Hodgkin lymphomas that are considered incurable. The role of allogeneic hematopoietic SCT (HSCT) in the treatment of CTCL is not well defined but may provide potent graft-vs-lymphoma (GVL) activity independent of the conditioning therapy. We present outcomes of 12 extensively-pretreated patients with CTCL who underwent allogeneic HSCT using, most commonly, a reduced intensity conditioning regimen. Median age at diagnosis of CTCL was 49 years, and median time to transplantation from diagnosis was 3.3 years. Transplantation induced and maintained CR in six patients with active disease, supporting the presence of a GVL effect. TRM was low, and 42% of patients were alive and disease-free a median duration of 22 months after transplant. Two patients showed strong and direct evidence of a GVL-effect with a direct response to withdrawal of immunosuppression or to donor leukocyte infusion. Our data show that HSCT can provide long-term disease control in patients with advanced CTCL, which otherwise was refractory to immunotherapy and chemotherapy.

Treatment of PTLD with rituximab or chemotherapy.

Information regarding treatment of post-transplant lymphoproliferative disease (PTLD) beyond reduction in immunosuppression (RI) is limited. We retrospectively evaluated patients receiving rituximab and/or chemotherapy for PTLD for response, time to treatment failure (TTF) and overall survival (OS). Thirty-five patients met inclusion criteria. Twenty-two underwent rituximab treatment, with overall response rate (ORR) 68%. Median TTF was not reached at 19 months and estimated OS was 31 months. In univariable analysis, Epstein-Barr virus (EBV) positivity predicted response and TTF. LDH elevation predicted shorter OS. No patient died of rituximab toxicity and all patients who progressed underwent further treatment with chemotherapy. Twenty-three patients received chemotherapy. ORR was 74%, median TTF was 10.5 months and estimated OS was 42 months. Prognostic factors for response included stage, LDH and allograft involvement by tumor. These factors and lack of complete response (CR) predicted poor survival. Twenty-six percent of the patients receiving chemotherapy died of toxicity. Rituximab and chemotherapy are effective in patients with PTLD who fail or do not tolerate RI. While rituximab is well tolerated, toxicity of chemotherapy is marked. PTLD patients requiring therapy beyond RI should be considered for rituximab, especially with EBV-positive disease. Chemotherapy should be reserved for patients who fail rituximab, have EBV-negative tumors or need a rapid response.