Update from ASH 2011: Rituximab improves survival in patients with mantle cell lymphoma

By Peter Martin, MD

Until recently, the role of rituximab in treatment of mantle cell lymphoma (MCL) was unclear. Prior randomized trials demonstrated improved response rates to chemotherapy when combined with rituximab, but unlike other lymphomas, it had failed to demonstrate an improvement in survival. Two abstracts presented at the recent American Society of Hematology (ASH) meeting provided encouraging evidence regarding this most-important outcome.

Dr. Simon Rule presented the results of the recent UK National Cancer Research Institute trial comparing fludarabine/cyclophosphamide (FC) to FC plus rituximab (FCR) in patients of all ages with newly diagnosed MCL. The trial enrolled 370 patients with mostly intermediate and high-risk MCL and followed them for an average of 39 months. The addition of rituximab to FC improved response rate, complete response rate, time to progression, and overall survival. Combined with recent evidence from data registry studies and the data that has accumulated from prior trials, it is clear that standard of care first-line treatment of MCL should include rituximab.

Updated results from a European Mantle Cell Lymphoma Network trial (also presented at the meeting in Lugano last summer and discussed by Dr. Rebecca Elstrom in this blog) confirmed that rituximab maintenance administered to patients over 60 years of age after R-CHOP chemotherapy provided a significant survival benefit. Although longer follow-up and confirmatory trials are needed, rituximab maintenance may be considered standard of care for older patients not receiving more aggressive induction/consolidation regimens. The upcoming Intergroup trial for patients over 60 years of age will feature randomization between rituximab maintenance and maintenance with lenalidomide plus rituximab.

ASH Conference: Radioimmunotherapy as Part of First Line Therapy for Low Grade Lymphoma

By Rebecca Elstrom, MD

Update: this study is closed to enrollment. 

Radioimmunotherapy (RIT), or radiation targeted to lymphoma cells through conjugation to a monoclonal antibody, has long been known to be effective therapy in patients with relapsed indolent non-Hodgkin’s lymphomas.  Its use as first line therapy has been limited, however. This weekend at the American Society of Hematology (ASH) meeting, several studies exploring the use of RIT in initial therapy of low grade lymphomas, either alone or following chemotherapy, were reported.

Two studies explored the use of 90Y-ibritumomab tiuxetan (Zevalin) alone;  one presented by Dr. Pica of Genova on behalf of an Italian cooperative group exploring a single dose, and one presented by Dr. Illidge from the University of Manchester with fractionated dosing (multiple doses of the RIT, in this case 2). Both studies showed high response rates with this brief and simple strategy, and durations of remission comparable to front line chemotherapy with no excessive toxicity.

Two other studies explored the use of RIT as consolidation following initial chemotherapy. The first, presented by Dr. Press of the University of Washington, was a large multicenter study comparing Rituximab plus CHOP chemotherapy (R-CHOP) to CHOP followed by 131I-tositumomab (Bexxar). There was no difference between the two groups in response rate or duration of response. A caveat to this study is the fact that, at the time it was designed, there was concern that giving the anti-CD20 antibody rituximab prior to RIT would inhibit radiation dose delivery, as 131I-tositumomab also requires binding to CD20 in order to deliver the radiation dose to lymphoma cells. This concern does have support in laboratory studies, but it has become clear in the years since this study was designed that anti-CD20 antibody therapy with rituximab is a critical contributor to response and survival in follicular lymphoma. The second study of chemotherapy followed by RIT was presented by Dr. Fowler of MD Anderson Cancer Center. This group evaluated an induction chemotherapy regimen containing rituximab, fludarabine, mitoxantrone and dexamethasone (R-FND) followed by 90Y-ibritumomab tiuxetan. This study showed high response rates and long time to progression, but toxicity of the regimen was of some concern, possibly due to the fact that fludarabine has significant bone marrow suppressive effects, which is also the main side effect of RIT.

Overall, these presentations confirmed the impressive activity of RIT in low grade lymphoma, and extended the experience using RIT as part of first line therapy, demonstrating feasibility, safety and efficacy of this simple and very well tolerated therapeutic approach.

At Weill Cornell Medical College we are exploring radioimmunotherapy as first treatment of follicular lymphoma using a combined strategy of non-radiation tagged antibody to CD20 in combination with radio-labeled antibody against an alternative protein, CD22. This study is designed to maximize the benefit of anti-CD20 directed therapy in addition to radiation dose delivery by targeting the radio-labeled antibody to an alternative target. Click here to read more about this study.

Weill Cornell Researcher: A Personalized Approach for Targeting Cancer Tumors

Through a collaboration between researchers at Weill Cornell Medical College, Memorial Sloan-Kettering, and the National Cancer Institute, researchers have reported that a tumor-targeting compound called PU-H71 can reveal with great accuracy the set of altered pathways that contribute to malignancy, thus allowing physicians to “fish-out” entire networks of abnormal proteins in tumor cells.

One major obstacle in the fight against cancer is that anticancer drugs often affect normal cells in addition to tumor cells, resulting in significant side effects. Yet research into development of less harmful treatments geared toward the targeting of specific cancer-causing mechanisms is hampered by lack of knowledge of the molecular pathways that drive cancers in individual patients.

“A major goal of cancer research is to replace chemotherapy with drugs that correct specific molecular pathways disrupted by cancer,” said Weill Cornell’s  Dr. Ari Melnick, one of the study’s lead investigator. The research was published in Nature Chemical Biology.

The researchers have uncovered that PU-H71 can reveal, with great accuracy, the set of altered pathways contributing to malignancy, thus allowing physicians to “fish-out” entire networks of abnormal proteins in tumor cells. PU-H71 binds to these abnormal protein complexes which are part of protein networks supporting cancer cell growth, division and survival. This knowledge could lead to more targeted, effective and individualized therapies for the personalized treatment of cancer – a disease in which no two tumors are alike – while producing fewer side effects and ultimately sparing patients from undergoing chemotherapy.

Based on these findings Dr. Melnick and colleagues have received a multi-investigator collaborative grant from the National Cancer Institute in support of clinical trials for the treatment of cancer. Currently, patients are being recruited for the first clinical trial to test the safety of PU-H71 as a drug used for the treatment of a variety of tumors. Subsequent trials will include patients with cancers such as breast, lymphomas, and chemotherapy-resistant leukemia.