Yttrium-90-Ibritumomab Tiuxetan (Zevalin®) Radioimmunotherapy after Cytoreduction with ESHAP Chemotherapy in Patients with Relapsed Follicular Non-Hodgkin Lymphoma: Final Results of a Phase II Study.

BACKGROUND: Radioimmunotherapy (RIT) is effective in treating relapsed/refractory follicular lymphoma (FL), with durable remissions in first-line consolidation. We hypothesized that RIT with ibritumomab tiuxetan (Zevalin®) would result in durable remissions by eliminating minimal residual disease after cytoreduction. METHODS: Patients with FL received 2 cycles of ESHAP (etoposide, methylprednisolone, cytarabine, cisplatin) every 28 days, followed by Zevalin 4-6 weeks later if there was no disease progression and bone marrow biopsy showed < 25% involvement. RESULTS: Twenty-eight patients were treated, with a median age of 61 years, median of 3 prior therapies, 49% high-risk disease (Follicular Lymphoma International Prognostic Index, FLIPI), and 39% progressive disease. Three patients did not receive Zevalin due to residual bone marrow involvement. The main toxicities were cytopenias, with 11% febrile neutropenia. The overall response rate (ORR) was 72%, with 45% achieving complete response. With a median follow-up of 73 months, 1-year progression-free survival (PFS) was 38%, and median PFS was 10 months, but median overall survival (OS) was not reached. CONCLUSION: The study did not reach its primary endpoint of a 1-year PFS of 67.3%. Reasons for this could include low accrual, high-risk disease, and inadequate debulking provided by 2 cycles of ESHAP. However, this protocol was associated with tolerable toxicity, high ORR, and high OS. Further studies would optimize debulking and focus on high-risk FL patients.

Phase 2 Open-Label Study of Bortezomib, Cladribine, and Rituximab in Advanced, Newly Diagnosed, and Relapsed/Refractory Mantle-Cell and Indolent Lymphomas.

BACKGROUND: Mantle-cell lymphoma (MCL) and indolent non-Hodgkin lymphoma (iNHL) are incurable heterogeneous diseases characterized by relapse. There is a need for newer treatments in MCL and iNHL, especially in the relapsed/refractory (R/R) setting. We therefore investigated the novel combination of bortezomib (Velcade), cladribine, and rituximab (VCR) in front-line and R/R settings in MCL and iNHL (NCT00980395). PATIENTS AND METHODS: Eligible patients included adults with biopsy-proven CD20-positive MCL and iNHL who met the criteria for treatment. Rituximab 375 mg/m2 intravenous (IV) day 1, cladribine 4 mg/m2 IV days 1 to 5, and bortezomib 1.3 mg/m2 IV days 1 and 4 were administered every 28 days for 6 cycles. RESULTS: Twenty-four patients were enrolled onto the study with a median follow-up of 38.5 months. Median age was 66.5 years, and 46% had MCL. The most common adverse events were hematologic, with febrile neutropenia in 3 patients. Neuropathy was noted in 17% of patients, of which 8% was grade 3 or above. The overall response rate was 92%. For the entire cohort, and for MCL patients, the median progression-free survival and the median overall survival were not reached. The 2-year progression-free survival was 82% for the MCL group and 54% for the iNHL group; it was 80% for treatment-naive patients and 57% for R/R patients. CONCLUSION: VCR is effective in MCL and iNHL. Although hematologic toxicity can be an issue, this study demonstrates a high response rate to a novel combination and provides an alternative option in transplant-ineligible R/R MCL and iNHL.

A Phase II Exploratory Study of PXD-101 (Belinostat) Followed by Zevalin in Patients with Relapsed Aggressive High-Risk Lymphoma.

OBJECTIVE: Aggressive lymphomas (aNHL) including diffuse large B-cell lymphoma (DLBCL) have poor outcomes in relapsed refractory patients. Prior studies have demonstrated that loss of major histocompatibility complex class II (MHCII) expression in DLBCL is associated with poor survival. The objective of this single-arm phase II study was to evaluate if PXD-101 would increase MHCII expression, synergize with Zevalin, and improve clinical outcomes. METHODS: This was a single-center open-label phase II trial (NCT01686165) geared toward heavily pretreated patients with CD20-positive aNHL. The primary endpoint was overall response rate (ORR) in aNHL patients treated with 2 cycles of PXD-101 followed by restaging CT and 1 cycle of Zevalin. RESULTS: Five patients were enrolled, and all were heavily pretreated. Therapy was well tolerated, with nausea and vomiting being the most frequent adverse events. All patients progressed after receiving therapy; the study did not achieve the required ORR to proceed to the next stage. CONCLUSION: The pleotropic effects of histone deacetylase inhibition and lack of clinical biomarkers have precluded a priori identification of responding patients. Thus, while we report a negative trial of PXD-101 in combination with Zevalin, this study highlights the importance of a clinically feasible biomarker.