Ranjit Banwait

Weekly bortezomib in combination with temsirolimus in relapsed or relapsed and refractory multiple myeloma: a multicentre, phase 1/2, open-label, dose-escalation study.

BACKGROUND Multiple myeloma is the second most prevalent haematological malignancy and is incurable. Our aim was to assess the response and safety of the combination of temsirolimus (an mTOR inhibitor) and bortezomib in patients with relapsed or refractory multiple myeloma. METHODS We did an open-label, dose-escalation study in three centres in the USA. Patients were enrolled from June, 2007, to December, 2009. Eligible patients were aged 18 years or older with relapsed or relapsed and refractory multiple myeloma after one or more treatment (including lenalidomide, bortezomib, or thalidomide), with an Eastern Cooperative Oncology Group performance status of 0-2. Patients were assigned a dose level in the order of their entry into the study. Phase 1 was to assess the safety and establish the maximum tolerated dose (MTD) of the combination and phase 2 was to assess overall response rate at the MTD. Intravenous temsirolimus was given at 15 or 25 mg and intravenous bortezomib at 1·3 or 1·6 mg/m(2) once a week, with dose escalation until dose-limiting adverse events were recorded in two of the three people in the dose cohort. Use of steroids were not permitted. The primary endpoint was the proportion of patients with a partial response or better. Analyses were done on an intention-to-treat basis, with all patients who had been enrolled included. The study is registered with ClinicalTrials.gov, number NCT00483262. FINDINGS 20 patients were enrolled into the phase 1 study and 43 into phase 2. All patients were heavily pretreated (median five lines in the phase 1 cohort, and four lines in the phase 2 cohort). The MTD was determined to be 1·6 mg/m(2) bortezomib on days 1, 8, 15, and 22 in combination with 25 mg temsirolimus on days 1, 8, 15, 22, and 29, for a cycle of 35 days. In the phase 2 study, the proportion of patients with a partial response or better was 33% (14 of 43; 90% CI 21-47). Long-term follow-up of patients is ongoing. There were three deaths during treatment in the phase 1 and 2 studies: one patient died of septic shock in the phase 1 study; one patient died with H1N1 influenza infection and one died with cardiac amyloid and ventricular arrhythmia unrelated to treatment in the phase 2 study. In the phase 1 study, the most common treatment-related grade 3-4 adverse events were thrombocytopenia (13 patients), lymphopenia (ten), neutropenia (nine), leucopenia (seven), and anaemia (five). In the phase 2 study, the most common treatment-related grade 3-4 adverse events were thrombocytopenia (25 patients), lymphopenia (24), neutropenia (17), leucopenia (ten), anaemia (seven), and diarrhoea (five). Four patients in the phase 1 study had sensory peripheral neuropathy (grade 2 or less); in the phase 2 study, 11 had sensory peripheral neuropathy (all grade 2 or less) and seven motor peripheral neuropathy (one grade 3, six grade 2 or less). INTERPRETATION mTOR inhibitors could have a role in combination with weekly bortezomib for the treatment of patients with relapsed and refractory multiple myeloma without the addition of steroids. FUNDING Millennium Inc, Pfizer Inc, Multiple Myeloma Research Foundation, and the Leukemia and Lymphoma Society.

Results of a phase 2 trial of the single-agent histone deacetylase inhibitor panobinostat in patients with relapsed/refractory Waldenström macroglobulinemia

The present study aimed to determine the safety and activity of the histone deacetylase inhibitor panobinostat in patients with relapsed/refractory Waldenström macroglobulinemia (WM). Eligibility criteria included patients with relapsed/refractory WM with any number of prior therapies. Patients received panobinostat at 30 mg 3 times a week; 12 of 36 (33%) patients were enrolled at 25 mg dose. A total of 36 patients received therapy. The median age was 62 years (range, 47-80) and the median number of prior therapies was 3 (range, 1-8). All of the patients had received prior rituximab. Minimal response (MR) or better was achieved in 47% of patients (90% confidence interval [CI], 33-62), with 22% partial remissions and 25% MR. In addition, 18 (50%) patients achieved stable disease and none showed progression while on therapy. The median time to first response was 1.8 months (range, 1.7-3.2). The median progression-free survival was 6.6 months(90% CI, 5.5-14.8). Grade 3 and 4 toxicities included thrombocytopenia (67%), neutropenia (36%), anemia (28%), leukopenia (22%), and fatigue (11%). We conclude that panobinostat is an active therapeutic agent in patients with relapsed/ refractory WM. This study (www.clinicaltrials.gov identifier: NCT00936611) establishes a role for histone deacetylase inhibitors as an active class of therapeutic agents in WM.

The Role of Serum Immunoglobulin Free Light Chain in Response and Progression in Waldenstrom Macroglobulinemia

Introduction: The serum free light chain (sFLC) has been widely used in the assessment of response in patients with multiple myeloma and other plasma cell dyscrasias. However, its use in Waldenstrom macroglobulinemia (WM) has not been previously assessed. We sought to examine the role of sFLC in response and progression of patients with WM. Methods: This study was conducted in a cohort of 48 patients with a diagnosis of WM, untreated (n = 20) or relapsed/refractory (n = 28), prospectively treated on a bortezomib and rituximab trial. Results: Involved FLC (iFLC) response occurred in 79% patients versus 60% by M-spike protocol criteria. The median time to response was shorter with iFLC than per protocol (2.1 and 3.7 months; P = 0.05). Progression defined using iFLC also correlated well to progression in the protocol (κ = 0.63). However, the median time to progression (TTP) was more rapid by iFLC than per protocol (13.7 and 18.9 months). We also confirmed that a flare in iFLC in post–rituximab therapy did not correlate with lack of response or shorter TTP. Conclusion: Involved sFLC may be a useful marker of tumor measurement, showing earlier response and progression compared with IgM or M-spike measurements. Clin Cancer Res; 17(9); 3013–8. ©2011 AACR.

Phase I/II trial of everolimus in combination with bortezomib and rituximab (RVR) in relapsed/refractory Waldenstrom macroglobulinemia

We examined the combination of the mammalian target of rapamycin inhibitor everolimus with bortezomib and rituximab in patients with relapsed/refractory Waldenstrom macroglobulinemia (WM) in a phase I/II study. All patients received six cycles of the combination of everolimus/rituximab or everolimus/bortezomib/rituximab followed by maintenance with everolimus until progression. Forty-six patients were treated; 98% received prior rituximab and 57% received prior bortezomib. No dose-limiting toxicities were observed in the phase I. The most common treatment-related toxicities of all grades were fatigue (63%), anemia (54%), leucopenia (52%), neutropenia (48%) and diarrhea (43%). Thirty-six (78%) of the 46 patients received full dose therapy (FDT) of the three drugs. Of these 36, 2 (6%) had complete response (90% confidence interval (CI): 1–16). In all, 32/36 (89%) of patients experienced at least a minimal response (90% CI: 76–96%). The observed partial response or better response rate was 19/36 (53, 90 CI: 38–67%). For the 36 FDT patients, the median progression-free survival was 21 months (95% CI: 12–not estimable). In summary, this study demonstrates that the combination of everolimus, bortezomib and rituximab is well tolerated and achieved 89% response rate even in patients previously treated, making it a possible model of non-chemotherapeutic-based combination therapy in WM.

The role of 18F‐FDG PET/CT imaging in Waldenstrom macroglobulinemia

Disease assessment in WM is dependent on the quantification of the IgM monoclonal protein and percent involvement of the bone marrow. There is a need for imaging studies that objectively measure tumor load in these patients. In this study, we sought to examine the role of combined FDG‐PET/CT imaging in the detection of tumor load and in the assessment of response to therapy. Thirty‐five patients were enrolled on a prospective study using bortezomib and rituximab therapy and were included in this study because they completed a pre‐ and post‐treatment FDG‐PET/CT imaging at one facility (12 newly diagnosed and 23 relapsed/refractory). The use of combined FDG‐PET/CT imaging showed positive findings in 83% of patients with WM, unlike prior studies using conventional imaging that indicate that only 20% of patients have lymphadenopathy or hepatosplenomegaly. Moreover, 43% of patients had abnormal bone marrow uptake on FDG‐PET imaging that can potentially help in the assessment of their tumor load, especially with heterogenous sampling of the bone marrow. There was no statistical correlation between EORTC response criteria for FDG‐PET/CT and response by monoclonal protein. This is the first study to examine the role of FDG‐PET/CT imaging in WM. Future studies should examine the role of FDG‐PET/CT in conjunction with monoclonal protein response in the assessment of progression‐free survival in patients with WM. Am. J. Hematol., 2011.

Extramedullary Waldenström macroglobulinemia.

Disease assessment in Waldenstrom Macroglobulinemia (WM) is dependent on the percent involvement of B‐cell neoplasm in the bone marrow and IgM paraprotein in the serum. A subset of patients also demonstrates extramedullary involvement, which is infrequently examined. The role of extramedullary involvement in the diagnosis and prognosis of WM is poorly understood. The purpose of this study is to report the characteristics of WM patients with extramedullary disease (EMD). Nine hundred and eight‐five patients with WM were evaluated at one academic center and the presence of EMD was assessed in these patients. Forty‐three (4.4%) patients were identified to have EMD. Nine (21%) patients presented with involvement at WM diagnosis, while 34 (79%) developed EMD post‐therapy for WM. Most frequent EMD sites involved were pulmonary (30%), soft tissue (21%), cerebrospinal fluid (23%), renal (8%), and bone (9%). The median overall survival at 10 years was 79% (95% CI: 57–90%). This is the first study to describe the clinical characteristics, response and overall survival in patients with extramedullary WM. Further studies to define the molecular characteristics of this entity and mechanisms of its development are warranted. Am. J. Hematol. 90:100–104, 2015.

Mechanisms of Activity of the TORC1 Inhibitor Everolimus in Waldenstrom Macroglobulinemia

Purpose: The TORC1 inhibitor everolimus has previously shown significant activity as a single agent in hematologic malignancies, with reported responses of 30% to 70% in Waldenstrom macroglobulinemia. However, the specific mechanisms by which this class of mTOR inhibitors exerts anti–Waldenstrom macroglobulinemia activity have not been fully investigated. We therefore sought to dissect the mechanisms of everolimus-dependent modulation of Waldenstrom macroglobulinemia cell survival. Experimental Design: We confirmed that everolimus targets mTOR in patients treated with everolimus and responding to therapy. We evaluated the effect of everolimus on proliferation and survival of primary Waldenstrom macroglobulinemia cells, as well as of other IgM-secreting lymphoma cell lines. Everolimus-dependent mechanisms of induced apoptosis and its effect on Waldenstrom macroglobulinemia cells in the context of bone marrow microenvironment have been also evaluated. miRNA-155 loss-of-function studies were conducted. Moreover, the combinatory effect of bortezomib and rituximab has been tested. Results: We showed that everolimus targeted mTOR downstream signaling pathways, ex vivo, in patients responding to everolimus treatment. Everolimus induced toxicity in primary Waldenstrom macroglobulinemia cells, as well as in other IgM-secreting lymphoma cells, supported by cell-cycle arrest and caspase-dependent and -independent induction of apoptosis. Importantly, everolimus targeted Waldenstrom macroglobulinemia cells even in the context of bone marrow milieu, where it affected migration, adhesion, and angiogenesis. Everolimus-dependent anti–Waldenstrom macroglobulinemia activity was partially driven by miRNA-155. Moreover, everolimus synergized with bortezomib and rituximab in targeting Waldenstrom macroglobulinemia cells, as shown by synergistic inhibition of p65/ and p50/NF-κB activities. Conclusions: These findings provide a better understanding of the mechanisms that are responsible for everolimus-induced anti–Waldenstrom macroglobulinemia activity. Clin Cancer Res; 18(24); 6609–22. ©2012 AACR.