Jae Werndli

Bortezomib-resistant nuclear factor-kappaB activity in multiple myeloma cells.

Bortezomib (Velcade/PS341), a proteasome inhibitor used in the treatment of multiple myeloma (MM), can inhibit activation of nuclear factor-κB (NF-κB), a family of transcription factors often deregulated and constitutively activated in primary MM cells. NF-κB can be activated via several distinct mechanisms, including the proteasome inhibitor–resistant (PIR) pathway. It remains unknown what fraction of primary MM cells harbor constitutive NF-κB activity maintained by proteasome-dependent mechanisms. Here, we report an unexpected finding that constitutive NF-κB activity in 10 of 14 primary MM samples analyzed is refractory to inhibition by bortezomib. Moreover, when MM cells were cocultured with MM patient-derived bone marrow stromal cells (BMSC), microenvironment components critical for MM growth and survival, further increases in NF-κB activity were observed that were also refractory to bortezomib. Similarly, MM-BMSCs caused PIR NF-κB activation in the RPMI8226 MM cell line, leading to increased NF-κB–dependent transcription and resistance to bortezomib-induced apoptosis. Our findings show that primary MM cells frequently harbor PIR NF-κB activity that is further enhanced by the presence of patient-derived BMSCs. They also suggest that this activity is likely relevant to the drug resistance development in some patients. Further elucidation of the mechanism of PIR NF-κB regulation could lead to the identification of novel diagnostic biomarkers and/or therapeutic targets for MM treatment. (Mol Cancer Res 2008;6(8):1356–64)

Bortezomib-Resistant Nuclear Factor-κB Activity in Multiple Myeloma Cells

Bortezomib (Velcade/PS341), a proteasome inhibitor used in the treatment of multiple myeloma (MM), can inhibit activation of nuclear factor-κB (NF-κB), a family of transcription factors often deregulated and constitutively activated in primary MM cells. NF-κB can be activated via several distinct mechanisms, including the proteasome inhibitor–resistant (PIR) pathway. It remains unknown what fraction of primary MM cells harbor constitutive NF-κB activity maintained by proteasome-dependent mechanisms. Here, we report an unexpected finding that constitutive NF-κB activity in 10 of 14 primary MM samples analyzed is refractory to inhibition by bortezomib. Moreover, when MM cells were cocultured with MM patient-derived bone marrow stromal cells (BMSC), microenvironment components critical for MM growth and survival, further increases in NF-κB activity were observed that were also refractory to bortezomib. Similarly, MM-BMSCs caused PIR NF-κB activation in the RPMI8226 MM cell line, leading to increased NF-κB–dependent transcription and resistance to bortezomib-induced apoptosis. Our findings show that primary MM cells frequently harbor PIR NF-κB activity that is further enhanced by the presence of patient-derived BMSCs. They also suggest that this activity is likely relevant to the drug resistance development in some patients. Further elucidation of the mechanism of PIR NF-κB regulation could lead to the identification of novel diagnostic biomarkers and/or therapeutic targets for MM treatment. (Mol Cancer Res 2008;6(8):1356–64)

VcR-CVAD induction chemotherapy followed by maintenance rituximab in mantle cell lymphoma: a Wisconsin Oncology Network study.

Intensive chemotherapy regimens are not feasible in many adults with mantle cell lymphoma (MCL). We sought to build upon our previous experience with a non‐intensive regimen, modified R‐hyperCVAD chemotherapy (rituximab, cyclophosphamide, vincristine, doxorubicin, dexamethasone) with maintenance rituximab (MR), by the incorporation of bortezomib (VcR‐CVAD) and the extension of MR beyond 2 years. Patients with previously untreated MCL received VcR‐CVAD chemotherapy every 21 d for six cycles. Patients achieving at least a partial response to induction chemotherapy received rituximab consolidation (375 mg/m2 × 4 weekly doses) and MR (375 mg/m2 every 12 weeks × 20 doses). The primary end points were overall and complete response (CR), and secondary endpoints were progression‐free (PFS) and overall survival (OS). Thirty patients were enrolled, with a median age of 61 years. All patients had advanced stage disease, and 60% had medium/high MCL International Prognostic Index risk factors. A CR or unconfirmed CR was achieved in 77% of patients. After a median follow‐up of 42 months, the 3‐year PFS and OS were 63% and 86%, respectively. The observed 3‐year PFS and OS with VcR‐CVAD in MCL were comparable to reported outcomes with more intensive regimens. A cooperative group trial (E1405) is attempting to replicate these promising results.

Maintenance rituximab following induction chemo-immunotherapy for mantle cell lymphoma: long-term follow-up of a pilot study from the Wisconsin Oncology Network.

Mantle cell lymphoma (MCL) is challenging to manage, with a median survival of 3–5 years. While intensive strategies are often appropriate for younger patients, these approaches are often not appropriate for older patients. In 2006, we reported our initial results using modified R-hyperCVAD (rituximab with hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone) with maintenance rituximab. The complete response rate was 64%, and median progression-free survival (PFS) 37 months. Herein, we update our results, now with a median follow-up of 62 months. The median PFS is unchanged and the median overall survival (OS) is 70 months. The proportion of patients surviving at 5 years is 62%, comparable to studies using intensive strategies in similar patient populations. No late toxicities were noted in our cohort. These long-term results suggest that the modified R-hyperCVAD regimen with maintenance rituximab is an excellent option for older patients with newly diagnosed mantle cell lymphoma.

Phase II study of arsenic trioxide and ascorbic acid for relapsed or refractory lymphoid malignancies: a Wisconsin Oncology Network study†

Arsenic trioxide (As2O3) has established clinical activity in acute promyelocytic leukaemia and has pre‐clinical data suggesting activity in lymphoid malignancies. Cell death from As2O3 may be the result of oxidative stress. Agents which deplete intracellular glutathione, such as ascorbic acid (AA), may potentiate arsenic‐mediated apoptosis. This multi‐institution phase II study investigated a novel dosing schedule of As2O3 and AA in patients with relapsed or refractory lymphoid malignancies. Patients received As2O3 0.25 mg/kg IV and AA 1000 mg IV for five consecutive days during the first week of each cycle followed by twice weekly infusions during weeks 2–6. Cycles were repeated every 8 weeks. The primary end point was objective response. In a subset of patients, sequential levels of intracellular glutathione and measures of Bcl‐2 and Bax gene expression were evaluated in peripheral blood mononuclear cells during treatment. Seventeen patients were enrolled between March 2002 and February 2004. The median age was 71, and the majority of enrolled patients had non‐Hodgkins lymphoma (12/17). Sixteen patients were evaluable, and one patient with mantle cell lymphoma achieved an unconfirmed complete response after five cycles of therapy for an overall response rate of 6%. The trial, which had been designed as a two‐stage study, was closed after the first stage analysis due to lack of activity. Haematologic toxicities were the most commonly reported events in this heavily pre‐treated population, and comprised the majority of grade 3 and 4 toxicities. Intracellular depletion of glutathione was not consistently observed during treatment. As2O3 and AA in this novel dosing strategy was generally well tolerated but had limited activity in patients with relapsed and refractory lymphoid malignancies. Copyright

Phase II Study of Weekly Low-Dose Paclitaxel for Relapsed and Refractory Non-Hodgkin's Lymphoma: A Wisconsin Oncology Network Study

This study was performed to determine the clinical activity and safety of weekly low-dose paclitaxel (90 mg/m2) given as a 1-hour infusion in patients with relapsed and refractory non-Hodgkins lymphoma (NHL). Thirty patients were treated on a phase II protocol conducted at the University of Wisconsin Comprehensive Cancer Center and within the Wisconsin Oncology Network (WON). A cycle of therapy was defined as paclitaxel at 90 mg/m2 weekly for 6 consecutive weeks followed by a 2-week rest period. Cycles were repeated as long as there was no disease progression or unacceptable toxicity. In general, the patients were heavily pretreated with a median of 4 prior therapies (range 2–11), and 73% were refractory to the most recent systemic therapy. The median age was 70 (range 44–97). All NHL histological subtypes were eligible. Of the 30 eligible patients enrolled, 26 were evaluable for response and 28 for toxicity. The overall response rate was 23% (95% confidence interval (CI) 9.0–43.7%). One patient had a complete response, and 5 patients had partial responses. The median response duration was 3.2 months (range 1.4–11.8 months). The median event-free survival was 1.9 months. The major toxicity was neuropathy. Despite the limited marrow reserve in this patient population, myelosuppression was minimal. Paclitaxel given in this dose and schedule has modest activity in previously treated non-Hodgkins lymphoma. The response rate appears similar to other reports using different doses and schedules. Myelosuppression appears less with this schedule than with other schedules.

Bortezomib-Resistant Nuclear Factor- B Activity in Multiple Myeloma Cells

Bortezomib (Velcade/PS341), a proteasome inhibitor used in the treatment of multiple myeloma (MM), can inhibit activation of nuclear factor-κB (NF-κB), a family of transcription factors often deregulated and constitutively activated in primary MM cells. NF-κB can be activated via several distinct mechanisms, including the proteasome inhibitor–resistant (PIR) pathway. It remains unknown what fraction of primary MM cells harbor constitutive NF-κB activity maintained by proteasome-dependent mechanisms. Here, we report an unexpected finding that constitutive NF-κB activity in 10 of 14 primary MM samples analyzed is refractory to inhibition by bortezomib. Moreover, when MM cells were cocultured with MM patient-derived bone marrow stromal cells (BMSC), microenvironment components critical for MM growth and survival, further increases in NF-κB activity were observed that were also refractory to bortezomib. Similarly, MM-BMSCs caused PIR NF-κB activation in the RPMI8226 MM cell line, leading to increased NF-κB–dependent transcription and resistance to bortezomib-induced apoptosis. Our findings show that primary MM cells frequently harbor PIR NF-κB activity that is further enhanced by the presence of patient-derived BMSCs. They also suggest that this activity is likely relevant to the drug resistance development in some patients. Further elucidation of the mechanism of PIR NF-κB regulation could lead to the identification of novel diagnostic biomarkers and/or therapeutic targets for MM treatment. (Mol Cancer Res 2008;6(8):1356–64)

Bendamustine + rituximab chemoimmunotherapy and maintenance lenalidomide in relapsed, refractory chronic lymphocytic leukaemia and small lymphocytic lymphoma: A Wisconsin Oncology Network Study

Bendamustine + rituximab (BR) has demonstrated high response rates in relapsed/refractory (R/R) chronic lymphocytic leukaemia (CLL) and small lymphocytic lymphoma (SLL). However, progression‐free survival (PFS) after BR is <18 months. This study was designed to determine if maintenance lenalidomide after BR induction could improve PFS in R/R CLL/SLL. Thirty‐four patients with R/R CLL/SLL who had received 1–5 prior chemotherapy regimens were treated with 6 cycles of BR induction. Patients achieving at least a minor response received twelve 28‐d cycles of lenalidomide 5–10 mg/d. The primary endpoint was PFS. The median age was 67 years, with a median of 2 prior therapies. Eleven patients had confirmed presence of 17p and/or 11q deletions. Twenty‐five (74%) completed 6 cycles of induction BR (response rate 56%). Nineteen (56%) patients received maintenance lenalidomide; only 6 patients completed the intended 12 cycles, highlighting the limited feasibility of lenalidomide in this setting, primarily due to haematological and infectious toxicities. The observed median PFS of 18·3 months is not significantly different from that of BR induction in R/R CLL/SLL without maintenance therapy (15·2 months). It is possible that lenalidomide maintenance may be more feasible and effective in the front‐line setting, which is being tested in an ongoing trial (NCT01754857).

Rituximab and CHOP Chemotherapy Plus GM-CSF for Previously Untreated Diffuse Large B-Cell Lymphoma in the Elderly: A Wisconsin Oncology Network Study

PURPOSE Human recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) may potentiate rituximab activity by upregulating CD20 expression and activating effector cells necessary for antibody-dependent cellular cytotoxicity. GM-CSF was combined with standard rituximab + CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone) chemotherapy (R-CHOP) in the treatment of elderly patients with de novo diffuse large B-cell lymphoma (DLBCL). PATIENTS AND METHODS Thirty-eight patients over the age of 60 years with newly diagnosed DLBCL were treated with R-CHOP every 21 days for 6-8 cycles and GM-CSF 250 µg/m2 per day on days 3-10. Patients were evaluated for response after cycles 4, 6, and 8. The primary endpoint was the rate of complete response, and secondary endpoints were progression-free survival (PFS), event-free survival, and overall survival (OS). RESULTS Thirty-eight patients were enrolled, with a median age of 72 years, and 29% of patients having high-risk disease (International Prognostic Index [IPI] score ≥ 4). A complete or unconfirmed complete response (CR) was achieved in 53% of patients. After a median follow-up of 51.1 months, the 3-year PFS and OS were 78% and 84%. Twenty-one percent of patients discontinued protocol treatment because of chemotherapy-related toxicity and 16% because of GM-CSF toxicity. Dose intensity for planned chemotherapy cycles was 81.1%. CONCLUSION These data suggest that survival outcomes may be modestly improved when GM-CSF is combined with R-CHOP in the treatment of elderly DLBCL. GM-CSF had toxicity precluding planned administration in 16% of patients, which may limit usefulness of this agent. Further investigation of GM-CSF in combination with rituximab-containing chemotherapy is warranted.

VcR-CVAD Induction Chemotherapy Followed by Maintenance Rituximab Produces Durable Remissions in Mantle Cell Lymphoma: A Wisconsin Oncology Network Study

Introduction VcR‐CVAD was developed as an intermediate‐intensity induction regimen with maintenance rituximab (MR) to improve remission durations after first‐line therapy for mantle cell lymphoma (MCL) in older and younger patients with MCL. Patients and Methods Patients with previously untreated MCL received VcR‐CVAD induction chemotherapy for 6 cycles (21‐day cycles). Patients achieving at least a partial response received rituximab consolidation (375 mg/m2 × 4 weekly doses) and MR (375 mg/m2 every 12 weeks × 20 doses). The primary endpoints were overall and complete response (CR), and the secondary endpoints were progression‐free survival (PFS) and overall survival (OS). Thirty patients were enrolled, with a median age of 61 years. There was an even distribution of patients < 60 years and ≥ 60 years. Mantle cell lymphoma international prognostic index medium‐ or high‐risk disease was present in 60%. The overall response rate observed was 90% (77% CR/unconfirmed CR). After a median follow‐up of 7.8 years, the 6‐year PFS and OS were 53% and 70%, respectively. There was no difference in 6‐year PFS or OS between the younger (age < 60 years) and older (age ≥ 60 years) subgroups. In a univariate analysis, lactate dehydrogenase, when analyzed for interaction with age, had a significant effect on PFS outcomes at 6 years. There were no pretreatment variables determined to have a significant effect on OS outcomes at 6 years. Conclusions Long‐term outcomes with VcR‐CVAD are comparable with more intensive inductions and consolidation approaches. MCL is biologically heterogeneous, and durable remission can be achieved with intermediate intensity therapy. MR appears to contribute to these excellent outcomes. Micro‐Abstract VcR‐CVAD with maintenance rituximab is an intermediate‐intensity regimen for older and younger patients with mantle cell lymphoma (MCL). Thirty patients were treated, with a primary endpoint of response and secondary endpoints of progression‐free and overall survival. After a median follow‐up of 7.8 years, no relapses were observed beyond 6 years. VcR‐CVAD has long‐term outcomes comparable with more intensive chemotherapy regimens.