Faculty Bibliography

BACKGROUND:Non-Hodgkin's lymphoma and multiple myeloma are often incurable and respond to a limited set of treatment options. The selective expression of CD74, the invariant chain of the MHC class II molecule, in these malignancies provides an attractive target for antibody-based therapy. OBJECTIVE:This review evaluates the preclinical data for milatuzumab, a humanized antibody targeting CD74, as a treatment for non-Hodgkin's lymphomas and multiple myeloma. METHODS:A review of the literature was carried out using PubMed. Current Phase I protocols using milatuzumab are summarized. RESULTS/CONCLUSION/CONCLUSIONS:Milatuzumab is cytotoxic to lymphoma and multiple myeloma cell lines and mouse-human xenografts. The efficacy dramatically increases when milatuzumab is attached to a toxin or a radioactive agent. Phase I trials of milatuzumab are now underway in human subjects with lymphoma and multiple myeloma.

Angiogenesis, the growth of new blood vessels, requires dynamic expansion, assembly and stabilization of vascular endothelial cells in response to proangiogenic stimuli. Antiangiogenic strategies have become an important therapeutic modality for solid tumors. While many aspects of postnatal pathological angiogenesis have been extensively studied in the context of nonhematopoietic neoplasms, the precise role of these processes in lymphoma pathogenesis is under active investigation. Lymphoma growth and progression is potentiated by at least two distinct angiogenic mechanisms: autocrine stimulation of tumor cells via expression of vascular endothelial growth factor (VEGF) and VEGF receptors by lymphoma cells, as well as paracrine influences of proangiogenic tumor microenvironment on both local neovascular transformation and recruitment of circulating bone marrow-derived progenitors. Lymphoma-associated infiltrating host cells including hematopoietic monocytes, T cells and mesenchymal pericytes have increasingly been associated with the pathogenesis and prognosis of lymphoma, in part providing perivascular guidance and support to neoangiogenesis. Collectively, these distinct angiogenic mechanisms appear to be important therapeutic targets in selected non-Hodgkin's lymphoma (NHL) subtypes. Understanding these pathways has led to the introduction of antiangiogenic treatment strategies into the clinic where they are currently under assessment in several ongoing studies of NHL patients.

PURPOSE/OBJECTIVE:This is a multicenter phase I/II dose-finding study in relapsed/refractory B-cell non-Hodgkin's lymphoma (NHL) evaluating veltuzumab, a humanized anti-CD20 antibody with structure-function differences from chimeric rituximab. PATIENTS AND METHODS/METHODS:Eighty-two patients (median age, 64 years; 79% stage III/IV, one to nine prior treatments) received four once-weekly doses of 80 to 750 mg/m(2) of veltuzumab and were assessed for safety, efficacy, pharmacodynamics, pharmacokinetics, and immunogenicity. RESULTS:Veltuzumab was well tolerated, with no grade 3 to 4 drug-related adverse events despite short infusion times (typically 2 hours initially, 1 hour subsequently at doses < 375 mg/m(2)). In follicular lymphoma, 24 (44%) of 55 patients had objective responses (OR), with 15 (27%) complete responses (CRs) or CRs unconfirmed (CRus) by International Working Group criteria, and with some responses occurring despite two to five prior rituximab-containing regimens, less favorable prognosis (elevated lactate dehydrogenase, tumors > 5 cm, and Follicular Lymphoma International Prognostic Index > or = 2), and at all dose levels. The CRs/CRus were durable (median duration, 19.7 months), with five patients still ongoing (15.9 to 37.6 months duration). In marginal zone lymphoma, five (83%) of six patients had ORs, with two CRs/CRus (33%), and in diffuse large B-cell lymphoma, three (43%) of seven patients achieved partial responses. At all dose levels studied, B cells were depleted after the first infusion, veltuzumab serum half-lives were similar after the fourth infusion, and mean antibody serum levels exceeded values considered important for anti-CD20 therapy (ie, 25 microg/mL). CONCLUSION/CONCLUSIONS:Veltuzumab appeared safe and active at all tested doses, encouraging further study, including dose levels less than those typically used with rituximab.

The infiltration of nonmalignant cells surrounding the Reed-Sternberg cells within the tumors of Hodgkin lymphoma (HL) might be central to the pathophysiology of the disease. Severe sepsis results in a flood of cytokines that activate the immune system and is associated with generalized lymphocyte apoptosis. We report on 2 patients with HIV infection and HL who achieved durable complete remissions following only one cycle of chemotherapy that was complicated by neutropenic sepsis. An understanding of the pathophysiology of sepsis and immunologic activation that appear to have led to these long-term remissions might lead to novel therapeutic approaches for patients with HL.

Mantle cell lymphoma (MCL) is a distinct subtype of non-Hodgkin lymphoma that remains incurable, and is associated with a median survival of approximately 5 years. Management of patients with relapsed or refractory disease is challenging. The major therapeutic goal in MCL management is to improve survival and quality of life whenever possible. Progress has been made in MCL therapy in the past decade based on clinical experimentation with novel agents and combinations. There is a growing list of conventional and novel agents in our armamentarium, consisting of not only additional chemotherapy combinations including high-dose approaches, but also biologically targeted reagents such as the monoclonal antibody rituximab, the proteasome inhibitor bortezomib, the mTOR inhibitor temsirolimus, immunomodulatory and antiangiogenic agents including thalidomide and lenalidomide, and cyclin-dependent kinase inhibitors, as well as a renewed interest in older compounds such as bendamustine and metronomic regimens. Efficacy evaluations for individual agents and rational combinations are in various stages of development, while treatment selection based on molecular and clinical prognostic scores is yet to be tested. In the absence of evidence demonstrating relative survival advantages of various second-line options, management of relapsed and refractory disease should be individualized. Involvement of a lymphoma center participating in clinical trials of novel MCL treatments is encouraged.

Mantle cell lymphoma (MCL) exhibits considerable molecular heterogeneity and complexity, and is regarded as one of the most challenging lymphomas to treat. With increased understanding of the pathobiology of MCL, it is proposed that MCL is the result of 3 major converging factors, namely, deregulated cell cycle pathways, defects in DNA damage responses, and dysregulation of cell survival pathways. In the present era of targeted therapies, these biologic insights have resulted in the identification of several novel rational targets for therapeutic intervention in MCL that are undergoing active clinical testing. To date, there is no standard of care in MCL. Several approaches including conventional anthracycline-based therapies and intensive high-dose strategies with and without stem cell transplantation have failed to produce durable remissions for most patients. Moreover, considering the heterogeneity of MCL, it is increasingly being recognized that risk-adapted therapy might be a relevant therapeutic approach in this disease. At the first and second Global Workshops on Mantle Cell Lymphoma, questions addressing advances in the pathobiology of MCL, optimization of existing therapies, assessment of current data with novel therapeutic strategies, and the identification of molecular or phenotypic risk factors for utilization in risk-adapted therapies were discussed and will be summarized herein.

This study investigated responses to retreatment with rituximab in chronic immune thrombocytopenic purpura (ITP) patients. Treatment with rituximab in chronic ITP patients induces long-lasting responses in approximately 30% of patients but even these patients may relapse. Twenty patients who had achieved a response to rituximab and relapsed were retreated with rituximab (375 mg/m(2)x 4); this data was analyzed retrospectively. Subsequently, 16 patients were prospectively randomized to receive rituximab with cyclophosphamide, vincristine and prednisone (R-CVP) or double dose rituximab (DDR). Retreatment with standard dose rituximab demonstrated responses similar to initial rituximab treatment in 15 of 20 patients. Neither of the two more intensive regimens (R-CVP, DDR) induced responses in any patient who had previously failed to respond to rituximab nor induced substantially longer-lasting responses among previous responders. No additional toxicity was noted with the DDR regimen, whereas R-CVP was not well tolerated. These results suggest that retreatment with standard dose rituximab induces similar responses in 75% of previously responding patients and is well tolerated. Neither combining rituximab with CVP nor doubling the dose of rituximab increased the response rate.

Burkitt lymphoma (BL) is a highly aggressive B-cell malignancy that occurs with increased frequency among patients infected with HIV. Until recently, the immunocompromised state of patients with HIV and BL was generally deemed to preclude the use of the intensive chemotherapeutic regimens used to treat HIV-negative patients due to toxicity issues. However, the advent of highly active antiretroviral therapy (HAART) and the mounting evidence that less intensive lymphoma regimens are ineffective in BL have led investigators to treat HIV-positive patients with the same chemotherapy now established as the standard of care for immunocompetent patients. Data suggest that these current approaches, along with supportive care, may result in improved patient outcomes. In contrast, the role of adjunctive immunotherapy with rituximab in HIV-BL remains undefined. Further studies, including randomized clinical trials, are needed to better delineate the optimal treatment for patients with this devastating disease.

This trial determined the safety and efficacy of the combination regimen clarithromycin (Biaxin), lenalidomide (Revlimid), and dexamethasone (BiRD) as first-line therapy for multiple myeloma. Patients received BiRD in 28-day cycles. Dexamethasone (40 mg) was given orally once weekly, clarithromycin (500 mg) was given orally twice daily, and lenalidomide (25 mg) was given orally daily on days 1 to 21. Objective response was defined by standard criteria (ie, decrease in serum monoclonal protein [M-protein] by at least 50%, and a decrease in urine M-protein by at least 90%). Of the 72 patients enrolled, 65 had an objective response (90.3%). A combined stringent and conventional complete response rate of 38.9% was achieved, and 73.6% of the patients achieved at least a 90% decrease in M-protein levels. This regimen did not interfere with hematopoietic stem-cell harvest. Fifty-two patients who did not go on to receive transplants received continued therapy (complete response, 37%; very good partial response, 33%). The major adverse events were thromboembolic events, corticosteroid-related morbidity, and cytopenias. BiRD is an effective regimen with manageable side effects in the treatment of symptomatic, newly diagnosed multiple myeloma. This trial was registered at www.clinicaltrials.gov as #NCT00151203.

A total of 28 treatment-naïve patients with stage II or III multiple myeloma (MM) were treated with the combination of clarithromycin, lenalidomide, and dexamethasone (BiRD). Stem cells were collected following granulocyte-colony stimulating factor (G-CSF) or cyclophosphamide (Cy) plus G-CSF mobilization at maximum response. Sufficient stem cells for 2 autologous stem cell transplants were collected from all patients mobilized with Cy plus G-CSF, versus 33% mobilized with G-CSF alone (P < .0001). The duration of prior lenalidomide therapy did not correlate with success of stem cell harvests (P = .91). In conclusion, Cy can be added to G-CSF for stem cell mobilization to successfully overcome the suppressive effect of prior treatment with lenalidomide.