Allogeneic hematopoietic cell transplantation following conditioning with 90Y-ibritumomab-tiuxetan

Results of a Phase II Trial of Allogeneic Hematopoietic Stem Cell Transplantation Using 90Y-Ibritumomab Tiuxetan (Zevalin) in Combination With Fludarabine and Melphalan in Patients With High-Risk B-Cell Non-Hodgkin's Lymphoma

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (alloHCT) is potentially curative for relapsed/refractory (r/r) B-cell non-Hodgkin's lymphoma (B-cell NHL). However, relapse remains a major cause of treatment failure, especially in patients with either positron emission tomography (PET)-positive and/or chemoresistant disease prior to alloHCT. 90Y-ibritumomab tiuxetan (Zevalin) is a radiolabeled anti-CD20 antibody which is a safe and effective therapy in multiple histologic subtypes of B-cell NHL and has also been incorporated in both autologous HCT (autoHCT) and alloHCT conditioning regimens.

OBJECTIVES

The purpose of this study was to evaluate the efficacy and confirm the safety of the radiolabeled anti-CD20 antibody ibritumomab tiuxetan (Zevalin) combined with the reduced intensity conditioning (RIC) regimen of fludarabine and melphalan (Flu/Mel) in patients with high-risk B-cell NHL.

STUDY DESIGN

We conducted a phase II trial (NCT00577278) of Zevalin with Flu/Mel in patients with high-risk B-cell NHL. We enrolled 41 patients from October 2007 to April 2014, all of whom had either a fully matched sibling or 8/8 or 7/8 matched unrelated donor (MUD). Patients received 111In-Zevalin (5.0 mCi) on day -21 pre-HCT, followed by 90Y-Zevalin (0.4 mCi/kg) on day -14. Fludarabine (25 mg/m2 daily) was given from days -9 to -5 and melphalan (140 mg/m2) was administered on day -4. All patients received rituximab 250 mg/m2 on day +8 and an additional dose on either day +1 or -21 depending on the baseline rituximab level. Patients with a low rituximab level were given rituximab on days -21 and -15. All patients received tacrolimus/sirolimus (T/S) with or without methotrexate (MTX) for graft-versus-host disease (GVHD) prophylaxis starting on day -3, and stem cells were infused on day 0.

RESULTS

The 2-year overall survival (OS) and progression-free survival (PFS) for all patients were 63% and 61%, respectively. The incidence of relapse at 2 years was 20%. Nonrelapse mortality (NRM) at day +100 and 1 year were 5% and 12%, respectively. The overall cumulative incidence of grade II-IV and III-IV acute GVHD (aGVHD) were 44% and 15%, respectively. Extensive chronic GVHD (cGVHD) occurred in 44% of patients. On univariate analysis, histology (diffuse large B cell lymphoma (DLBCL) vs. others) was negatively predictive for OS (P = .0013) and PFS (P = .0004), while histology (DLBCL vs. others, P = .0128) predicted for relapse. PET positivity pre-HCT did not correlate with any of the efficacy endpoints.

CONCLUSION

Addition of Zevalin to Flu/Mel is safe and effective in high-risk NHL and met the prespecific endpoint. Results were suboptimal in patients with DLBCL.

90Y-ibritumomab tiuxetan, fludarabine, busulfan and antithymocyte globulin reduced-intensity allogeneic transplant conditioning for patients with advanced and high-risk B-cell lymphomas

BACKGROUND

Patients with advanced B-cell non-Hodgkin's lymphoma (NHL) refractory to initial chemotherapy or relapsing after autologous stem-cell transplantation have a poor prognosis. Allogeneic stem-cell transplantation after reduced-intensity conditioning (RIC) regimen can be a therapeutic option. However, the high incidence of relapse remains a challenging issue. We speculated that the incorporation of (90)Y-Ibritumomab tiuxetan into a fludarabine-based RIC regimen would improve the lymphoma control without overwhelming toxicity. Our aim was to evaluate the safety of (90)Y-Ibritumomab tiuxetan in association with such a regimen in a prospective multicenter phase II trial.

PATIENTS AND METHODS

Thirty-one patients with advanced lymphoma from five distinct institutions were included between February 2008 and October 2010. Thirty patients in complete or partial response after failure of a median of 3 (range, 2-4) previous chemotherapy regimens including autologous transplant in 29 were evaluable for nonrelapse mortality (NRM) at day 100 post-transplant that was the primary end point.

RESULTS

With a median follow-up of 32 months (range, 29-60 months), the 2-year event-free and overall survivals of the whole study group were both 80% [95 confidence interval (CI) 60.8% to 90.5%). The 100-day and 2-year post-transplant cumulative incidences of NRM were 3.3% (95% CI 0.2% to 14.9%) and 13.3% (95% CI 5.4% to 33.2%), respectively. The 2-year cumulative incidence of relapse was 6.7% (95% CI 1.7% to 25.4%). The cumulative incidences of grade II-IV and extensive chronic graft-versus-host disease were 27% and 14%, respectively.

CONCLUSIONS

For chemosensitive advanced high-risk B-cell lymphoma, the addition of (90)Y-Ibritumomab tiuxetan to a RIC regimen based on fludarabine, busulfan and antithymocyte globulin followed by allogeneic transplant is safe and highly effective. clinicaltrials.gov: NCT00607854.

Dosimetric considerations in radioimmunotherapy and systemic radionuclide therapies: a review

Radiopharmaceutical therapy, once touted as the “magic bullet” in radiation oncology, is increasingly being used in the treatment of a variety of malignancies; albeit in later disease stages. With ever-increasing public and medical awareness of radiation effects, radiation dosimetry is becoming more important. Dosimetry allows administration of the maximum tolerated radiation dose to the tumor/organ to be treated but limiting radiation to critical organs. Traditional tumor dosimetry involved acquiring pretherapy planar scans and plasma estimates with a diagnostic dose of intended radiopharmaceuticals. New advancements in single photon emission computed tomography and positron emission tomography systems allow semi-quantitative measurements of radiation dosimetry thus allowing treatments tailored to each individual patient.

Superior long-term outcome of patients with early transformation of non-Hodgkin lymphoma undergoing stem cell transplantation

In this study, we discuss the results of patients with transformed lymphoma (TL) undergoing stem cell transplantation (SCT). Because of the paucity of literature on the treatment of TL, deciding on the optimal evidence-based treatment is a challenge. Herein, our results indicate that patients with early transformation may benefit the most from SCT.

BACKGROUND

Transformed non-Hodgkin's lymphoma arising from follicular lymphoma (TL) carries a poor prognosis with a median survival time after transformation reported to be approximately 1 year.

PATIENTS AND METHODS

Fifty-one consecutive patients with TL received SCT between January 2000 and December 2010 (autologous SCT, n = 44, allogeneic SCT, n = 7).

RESULTS

Thirty-six (70.5%) patients had an early transformation, defined as histologic evidence of transformation at the time of initial diagnosis or transformation within 1 year of follicular lymphoma. Fifteen patients had early stage disease (29%) and 36 (71%) had advanced stage disease on presentation. At the time of analysis, 37 patients were alive with an estimated 5-year overall survival (OS) and event free survival (EFS) of 61.8% and 45%, respectively. OS and EFS were not significantly different between types of transplant procedure. The major cause of transplant failure was disease recurrence, with estimated 2-year relapse rate of 37.4%. Importantly, early transformation was independently associated with improved OS (hazard ratio [HR] 3.29; P = .028) and EFS (HR 2.49; P = .029).

CONCLUSION

Our results indicate that an aggressive transplant approach should be considered first in patients with TL and emphasize the need to incorporate novel strategies (eg, immunomodulation) early post-SCT to prevent relapses as disease recurrence remains the major cause of failure in heavily pretreated patients.

Treatment options for transformed lymphoma: incorporating allogeneic stem cell transplantation in a multimodality approach

Transformed non-Hodgkin lymphoma (TL) arising from follicular lymphoma carries a poor prognosis, and the median survival time after transformation is approximately 10 to 12 months. Standard chemotherapy and radioimmunotherapy have offered promising responses; however, the duration of response does not appear to last long. Several studies evaluating the role of autologous stem cell transplantation (auto-SCT) as a salvage regimen have been reported, and a subset of patients benefit from this modality of treatment. With an improvement in supportive care, outcome after allogeneic stem cell transplantation (allo-SCT) has been improved significantly over past decades; however, very limited data are available for TL. In the era of emerging novel therapies, the actual timing, optimal conditioning regimens, and long-term impact of the type of stem cell transplantation (auto-SCT vs allo-SCT) is unclear. This review addresses the approaches to the management of patients with TL.

(90)Y-ibritumomab tiuxetan followed by reduced-intensity conditioning and allo-SCT in patients with advanced follicular lymphoma

RIC HSCT is a potentially curative therapeutic option for patients with advanced FL but disease relapse remains the most common cause of failure. Radioimmunoconjugates administered prior to RIC allogeneic HSCT may enhance cytoreduction and allow more time for graft versus lymphoma effect to develop without the associated toxicity of a myeloablative HSCT. We performed a retrospective study to describe the outcomes of patients with relapsed, refractory or transformed FL who received ⁹⁰Y ibritumomab tiuxetan followed by fludarabine and low-dose busulfan RIC allogeneic HSCT at the Dana-Farber Cancer Institute between 2006 and 2009, inclusively. Twelve patients were identified with a median age of 55 (40–66) years and a median number of lines of therapy of 5 (2–10). Two patients (17%) had transformed to a more aggressive histology and 5 (42%) had chemorefractory FL. Cumulative incidences of grade II–IV acute GVHD at 100 days were 17% (± 11%) and chronic GVHD at 12 months were 63% (±19%). Two-year non-relapse mortality was 18% (± 12%). Two-year OS and progression-free survival (PFS) were 83% (± 11%) and 74% (± 13%), respectively. This treatment is associated with favorable outcomes including acceptable rates of GVHD and relapse in advanced FL patients and warrants prospective studies.

Radioimmunotherapy for the treatment of non-Hodgkin lymphoma: current status and future applications

Radioimmunotherapy (RIT) has proved to be a safe and effective treatment for patients with relapsed or refractory indolent non-Hodgkin lymphoma (NHL) including rituximab-refractory follicular lymphoma. Further, FDA approval was recently granted for use in newly diagnosed follicular lymphoma as consolidative therapy immediately following induction chemotherapy. We detail herein the scope of clinical studies performed in relapsed/refractory and newly diagnosed indolent lymphoma and summarize the associated safety data. In addition, we discuss new applications of RIT that have been investigated in a variety of clinical scenarios (e.g. single-agent and sequential therapy in aggressive NHLs and as a component of stem cell transplant conditioning). The wide array of RIT-based studies have yielded encouraging data, although randomized controlled trials will be needed to prove superiority over conventional therapy. Novel therapeutic RIT-based strategies that continue to be explored include radiation-enhancing agents combined with RIT, pre-targeting, RIT fractionation, as well as the integration of new humanized antibodies. The field of RIT continues to evolve scientifically and grow clinically. A reappraisal of prior data and examination of recently published and ongoing studies will be important in recognizing the potential benefit of RIT in the treatment of NHL.

Radioimmunotherapy with yttrium-90-ibritumomab tiuxetan as part of a reduced- intensity conditioning regimen for allogeneic hematopoietic cell transplantation in patients with advanced non-Hodgkin lymphoma: results of a phase 2 study

Forty patients were enrolled in this phase 2 study combining radioimmunotherapy (RIT) using yttrium-90-ibritumomab-tiuxetan (15 MBq [0.4 mCi]/kg) with reduced-intensity conditioning (RIC) using fludarabine (90 mg/m2) and 2 Gy total body irradiation followed by allogeneic hematopoietic cell transplantation (HCT) from related (n = 13) or unrelated (n = 27) donors for the treatment of advanced non-Hodgkin lymphoma. Diagnoses were follicular lymphoma (n = 17), chronic lymphocytic leukemia (n = 13), mantle cell lymphoma (n = 8), marginal zone lymphoma (n = 1), and lymphoplasmacytic lymphoma (n = 1). Median age was 55 years (range, 34-68 years). All patients were high risk with refractory disease or relapse after preceding autologous HCT. No additional toxicities attributable to RIT were observed. Engraftment was rapid and sustained. Incidences of acute graft-versus-host disease 2-4 and chronic graft-versus-host disease were 43% and 53%, respectively. Kaplan-Meier–estimated nonrelapse mortality was 45% at 2 years. Twenty-two of 40 patients (55%) are alive, resulting in a Kaplan-Meier–estimated 2-year survival of 51% for all, 67% for follicular lymphoma, 49% for chronic lymphocytic leukemia, and 37% for mantle cell lymphoma patients. The combined use of RIT with RIC is feasible with acceptable toxicity, even in elderly and heavily pretreated patients. This study is registered at www.clinicaltrials.gov as #NCT00302757.

Unresolved issues in diffuse large B-cell lymphomas

For more than 25 years, the combination of cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) was considered the 'gold standard' for the treatment of aggressive lymphomas, 90% of which are diffuse large B-cell lymphomas (DLBCLs). After the demonstration of rituximab's single-agent activity in DLBCL, a pivotal trial in elderly patients demonstrated that combining rituximab with eight applications of CHOP significantly improved complete remission rates, and event-free and overall survival rates compared with CHOP alone. These positive results have meanwhile been confirmed by two additional randomized trials and have been extended to young patients with good-prognosis DLBCL by a fourth trial and rituximab, in combination with CHOP, has become accepted worldwide as the new standard for all DLBCL. Remaining issues concern biology-based approaches and the guidance of therapy by PET, the definition of the optimal dosage and schedule of rituximab for DLBCL, as well as the optimal chemotherapy regimen partner for rituximab. Finally, patients failing after rituximab-containing immunochemotherapy have a dismal prognosis and the treatment of these patients has become a prime challenge in the rituximab era.

Radioimmunotherapy and stem-cell transplantation in the treatment of aggressive B-cell lymphoma

High-dose chemotherapy and autologous stem-cell transplantation (ASCT) have an established therapeutic role in the treatment of chemo-sensitive relapsed aggressive lymphoma, but has limited success in chemo-refractory disease or in heavily pretreated, multiple relapsed patients. Recurrent disease is the major cause of treatment failure in all patient subsets and the majority is not cured. Methods for better eradication of underlying lymphoma are needed to improve outcome. Radioimmunotherapy (RIT) combines radiation delivered by radio-isotopes with the targeting effect of monoclonal antibodies. Two radioimmunoconjugates are currently approved for relapsed/resistant low-grade or transformed lymphoma: iodine-131 tositumomab and yttrium-90 ibritumomab tiuxetan. These agents are also effective in aggressive lymphoma. Radio-labeled antibodies are ideal candidates to combine with high-dose chemotherapy and ASCT. Their major toxicity is myelosuppression, which is easily reversed by ASCT and they can target disease sites with almost no added toxicity to normal tissues. RIT has been used in escalated doses as the sole treatment prior to ASCT or in standard or escalated doses combined with standard high-dose chemotherapy regimens. RIT was also combined with reduced-intensity conditioning and allogeneic SCT. Preliminary results are promising and suggest improved disease control with no added toxicity; however randomized studies are needed to confirm these initial observations.

Radioimmunotherapy-based conditioning regimens for stem cell transplantation

Radioimmunotherapy (RIT) combines the mechanism of action and targeting capability of monoclonal antibodies with the tumoricidal effect of radiation and has shown promising results in the treatment of various hematologic malignancies. Based on RIT's efficacy and safety profile, many investigators have evaluated its use in transplant conditioning regimens with the goal of improving long-term disease control with limited toxicity. In lymphoma, two basic transplant approaches targeting CD20 have emerged: (1) myeloablative doses of RIT with or without chemotherapy, and (2) standard nonmyeloablative doses of RIT combined with high-dose chemotherapy. Myeloablative RIT has been shown to be feasible and efficacious using escalated doses of iodine 131-tositumomab, yttrium 90-ibritumomab tiuxetan, and (131)I-rituximab with or without chemotherapy followed by autologous stem cell transplant (ASCT). The second approach predominantly has used standard doses of (90)Y-ibritumomab tiuxetan or (131)I-tositumomab plus BEAM chemotherapy (carmustine [BCNU], etoposide, cytarabine, melphalan) followed by ASCT. RIT targeting CD45, CD33, and CD66 prior to allogeneic transplantation also has been evaluated for the treatment of acute leukemia. Overall RIT-based transplant conditioning for lymphoma and leukemia has been shown to be safe, effective, and feasible with ongoing randomized trials currently underway to definitively establish its place in the treatment of hematologic malignancies.

Current status and future perspectives for yttrium-90 ((90)Y)-ibritumomab tiuxetan in stem cell transplantation for non-Hodgkin's lymphoma

Haematopoietic SCT is currently considered a therapeutic option mainly in relapsed or refractory non-Hodgkin's lymphoma (NHL) owing to high post-transplantation relapse rates and significant toxicity of conventional myeloablative conditioning for allogeneic SCT. Radiolabelled immunotherapy combines the benefits of monoclonal antibody targeting with therapeutic doses of radiation, and is a promising advance in the treatment of malignant lymphomas. It is now under investigation as a component of conditioning prior to SCT, with the aim of improving outcomes following SCT without increasing the toxicity of high-dose chemotherapy pre-transplant conditioning. An expert panel met at a European workshop in November 2006 to review the latest data on radiolabelled immunotherapy in the transplant setting, and its potential future directions, with a focus on (90)Y-ibritumomab tiuxetan. They reviewed data on the combination of standard/high/escalating dose (90)Y-ibritumomab tiuxetan with high-dose chemotherapy, and high/escalating dose (90)Y-ibritumomab tiuxetan as the sole myeloablative agent, prior to autologous SCT, and also (90)Y-ibritumomab tiuxetan as a component of reduced intensity conditioning prior to allogeneic SCT. The preliminary data are highly promising in terms of conditioning tolerability and patient outcomes following transplant; further phase II studies are now needed to consolidate these data and to investigate specific patient populations and NHL subtypes.

Lymphoid reconstruction and vaccines

Allogeneic HSCT is the most reliable, robust, and effective cell-based biotherapy currently available to pediatric and adult patients with hematologic malignancies. The central role of donor-derived lymphocytes in mediating an effective antitumor effect, preventing and controlling opportunistic infections, and causing GVHD is well documented in animal experiments and human trials. The profound lymphopenia after conditioning regimens coupled with molecular tools to distinguish host versus donor cells provides investigators a window into immune recovery after allogeneic HSCT. Serial analyses of T cell subsets linking immunophenotype with function have revealed the kinetics of donor-derived T cell recovery after allografting and provided insights into ways the immune system can be manipulated to augment the graft-versus-tumor (GVT) effect without inducing GVHD. As this review demonstrates, investigators are not limited to being passive observers of this immune reconstitution; rather, we have an opportunity to shape the allografted T cells repertoire to selectively augment immune function.

Antibody therapy in non-Hodgkin's lymphoma: the role of rituximab, 90Y-ibritumomab tiuxetan, and alemtuzumab

Targeting cancer cells with monoclonal antibodies has become an indispensable part of modern treatment against hematologic malignancies. The excitement of the first successful experimental results could be confirmed by large multicenter trials, thus paving the way for new approaches in first-line, relapse, and maintenance therapy. Three antibodies--rituximab, 90Y-ibritumomab tiuxetan, and alemtuzumab--are in clinical use worldwide and are reviewed in this chapter with a focus on practical information and fundamental principles of antibody-based therapy.