In this podcast, Cancer.Net Associate Editor Dr. Michael Williams will discuss some of the new research in lymphoma that was presented at the 2019 American Society of Hematology Annual Meeting, held December seventh through tenth in Orlando, Florida.
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In this podcast, Cancer.Net Associate Editor Dr. Michael Williams will discuss some of the new research in lymphoma that was presented at the 2019 American Society of Hematology Annual Meeting, held December seventh through tenth in Orlando, Florida. Dr. Williams is the Chief of the Hematology/Oncology Division and Director of the Hematologic Malignancies Program at the UVA Cancer Center. He is also the Byrd S. Leavell Professor of Medicine and Professor of Pathology at the University of Virginia School of Medicine. View Dr. Williams’ disclosures at Cancer.Net.
ASCO would like to thank Dr. Williams for discussing this research.
Dr. Williams: Hello, and thanks for joining us for this podcast. My name is Michael Williams. I'm Professor and Chief of Hematology/Oncology at the University of Virginia in Charlottesville. And I'm pleased to discuss some exciting advances in lymphoma that were presented at the American Society of Hematology meeting held in Orlando in December 2019. My disclosures are that my research group here at the university, through the university, has received research support from pharmaceutical companies AbbVie, Pharmacyclics, and Janssen, and I have received honoraria for speaking at conferences from Xian-Janssen in China. So what I'm going to talk about today are 2 reports about the management of localized diffuse large B-cell lymphoma, an update on a novel therapeutic approach for relapsed mantle cell lymphoma. And then, I'll finish with a brief introduction of an agent that is showing promise for treating highly resistant relapsed lymphoma that was presented in the plenary session during the ASH meeting.
So let's start with localized diffuse large B-cell lymphoma. So DLBCL is the most common subtype among the many forms of non-Hodgkin lymphoma. Usually, people present with advanced stage disease. But as many as 25 to 30 percent may have a disease that's localized to just 1 site or a very localized area of lymph nodes, so these would be stage I or stage ll patients. And the first report that I'll comment upon was presented by Dr. Laurie Sehn at the BC Cancer Agency in Vancouver, British Columbia. So they did a retrospective review looking at 319 patients treated in British Columbia over the past 15 years. So these were patients who had a nonbulky mass, they were localized disease. And the treatment currently for this disease is that people get either 6 cycles of a regimen such as rituximab and CHOP chemotherapy or more limited chemotherapy. Typically, 3 cycles of R-CHOP followed by radiation therapy. The importance of this study is that it is exploring a mechanism to de-escalate therapy, if you will, by avoiding the use of the radiation therapy. So what they did, is patients with localized disease received 3 cycles of rituximab plus CHOP therapy and then underwent a PET scan.
So PET scans, unlike CT scans, are nuclear-medicine imaging that shows the functional uptake of radioactive glucose by the sites involved by lymphoma. So if you become PET negative after the three cycles of rituximab, CHOP therapy, then it seems likely that you've got a very highly responsive disease, and you may be able to avoid radiation therapy. So they did the PET scan after 3 cycles, and for those who were PET negative, then those patients received 1 additional cycle of rituximab CHOP, and that was the end of their therapy. If they were still PET positive, then they moved on to radiation therapy to the involved area.
So what they found was quite interesting that of the 319 patients, 254 were negative after their PET scan. And so went on, virtually all of them, to just getting 1 more cycle of rituximab CHOP as planned. The outcomes for those patients were that very few of them relapsed over the next several years. They followed patients now, for about four years or more, in most cases, and they found that the overall, 5-year progression-free survival was 88% for those who were PET negative. For the subset of patients who were still PET positive, and got the radiation therapy, their outcome was somewhat worse, in that there was only 74% who were still progression free. The overall survival for these patients was 90%, at 5 years, for those who were PET negative and 77% for PET positive.
So what this study shows us, is that a PET scan after 3 cycles, can inform us about patients who are 90% likely to have good control of their disease, with just 4 treatments, and you can avoid the exposure to radiation therapy. Those who were still PET positive still did well: 3 out of 4 were still in remission beyond 5 years but not quite as good an outcome. So these are patients who may be candidates for an alternative approach to try to do better with their long-term cure rates. So that leads us to the second presentation that I want to discuss.
This was presented by Dr. Daniel Persky on behalf of the Southwest Oncology Group, which is part of the National Clinical Trials Network, in the United States. So they had a very similar approach. They studied patients with localized Stage 1 or 11, nonbulky diffuse large B-cell lymphoma, and they got standard rituximab CHOP therapy, and then a PET scan after the third cycle. Just as in the paper I discussed from British Columbia. Those who had negative PET scans got one additional cycle of rituximab CHOP. Those who were still PET positive got involved-field radiation therapy and treatment with a radio-labeled monoclonal antibody. Essentially, a radioactive form of rituximab, which has given us a single dose about a month after they'd finished their involved-field radiation therapy and then they got a follow-up PET scan, thereafter.
So this study went on for several years, at multiple sites around the country. They enrolled 132 patients, and of those patients, 110 were PET negative after their third cycle. So only 18 needed to go on to this additional radiation therapy and the systemic treatment with the radio immuno therapeutic called Ibritumomab tiuxetan. They followed these patients now for 4 and a half years, and only 5 patients have progressed, and only 2 have died of their lymphoma. So of those who progressed, 3 of them had gotten just the R-CHOP alone. There was another patient who was PET positive but declined getting the radiation therapy who progressed. And then, another patient who had only 1 treatment was rituximab CHOP but then went off treatment due to toxicity. So similar, and in fact, almost identical to the British Columbia report. Five-year freedom from progression of their disease was 87%, and the overall survival was 90%. So these patients can do quite well, since many times, the location for localized DLBCL is in the head neck. There can be significant late effects of radiation therapy. So I think these studies reassure us that patients with localized disease can have very durable outcomes and cure rates. It's important to note that there's a higher rate of late relapse beyond three years in patients with localized DLBCL compared to more diffuse extensive disease suggesting that there may be some differences in the biology of a localized disease. So very important data, and data that gives us the opportunity to de-escalate treatment in localized large cell lymphoma.
So let's switch gears and talk about mantle cell lymphoma. There's been a lot of progress in this disease over the past decade. Much of it related to the use of nonchemotherapy targeted agents such as Bruton’s tyrosine kinase inhibitors including ibrutinib and the Bcl-2 inhibitor, venetoclax. There was a study reported last year by an Australian group led by Dr. Constantine Tam. This study was updated at the ASH meeting with a longer follow up. So these were patients with Relapsed/Refractory disease, heavily pretreated. Many of them, previously, having had intensive chemotherapy and a stem cell transplant. And half of them had mutations in a gene called TP53, which is correlated with frequent chemotherapy resistance and high relapse rate. And what they found by combining the targeted agents ibrutinib and venetoclax, that they got very high response rates. The majority of patients responded although, there were a few who were primarily resistant, and about a third of patients, actually, got very deep remissions. PET negative and negative for minimal residual disease detection. If you look at the subset, of the highest risk patients, with the TP53 mutation, half of them achieved a complete response rate, and some of these patients have had durable responses. There have been a few patients who've had deep responses, who've been able to come off treatment. And overall, the duration of response at 2 and a half years is 74%.
But what this study shows us, is yet again, that these novel targeted drugs that are typically better tolerated than cytotoxic chemotherapy can have very good and indeed dramatic responses, and so is showing a lot of promise. It reminds us that in mantle cell, whether it's newly diagnosed or relapsed, that talking to your oncologist about clinical trial opportunities can often avail you of some of the most promising new approaches. And indeed, that's true for all forms of lymphoma, that clinical trial options should be part of the discussion with treatment planning.
I'm going to finish by just mentioning another novel agent that is being applied to patients with highly resistant relapsed disease. This is a molecule called mosunetuzumab, and this is a bispecific antibody. So there are a number of these now that are in clinical development, and some are FDA approved for treating leukemias and certain lymphomas. This one is designed to basically connect a body's immune system, the T cells, with the B-cell lymphomas by using an antibody that can recognize each of those and bring them physically together. So this was presented by Dr. Steven Schuster; it was a multinational study of this bispecific antibody in patients with very aggressive relapsed/refractory lymphomas including, diffuse large B-cell and transformed follicular lymphoma. And what they found in this study, is that response rates were 64%, with 42% of patients achieving a complete remission. So it's still early, but quite promising because these are patients who had failed CAR T-cell therapy. They may have failed transplant, or they were patients who needed a treatment to bridge them over to get to a CAR T or another treatment such as an allogeneic stem cell transplant.
The toxicities were generally manageable and similar to those seen with other bispecific antibodies. So it's early, but across subtypes of patients with aggressive and relapsed lymphoma, I think this is another promising molecule, that may well provide good therapeutic options via a clinical trial for patients who have very limited other options to manage their disease.
So thanks again for joining this podcast. There was a lot of other exciting data that we didn't have time to go through, so I encourage you to continue learning about what's new in the field, discussing with your oncologist, or with a consulting specialist in lymphoma, to make sure you can avail yourself of the best in current diagnostics and therapeutics. Thanks very much.
ASCO: Thank you, Dr. Williams. Learn more about lymphoma at www.cancer.net. And if this podcast was useful, please take a minute to subscribe, rate, and review the show on Apple Podcasts or Google Play.
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