Published on January 14, 2020
- MRD, or minimal residual disease, is a testing technique that recognizes very small amounts of CLL.
- With certain drugs like ibrutinib, CLL can still be present but inactive.
- The importance of MRD testing depends largely on the therapies used.
Leading chronic lymphocytic leukemia expert Dr. Jeff Sharman, from The US Oncology Network, joined Patient Power at a town meeting in Portland to discuss minimal residual disease (MRD) testing and how it helps determine the effectiveness of certain therapies. Watch as Dr. Sharman discusses commonly utilized tests for assessing CLL treatment response, capabilities and use of MRD testing, and how the results relate to the goals of treatment.
This town meeting is sponsored by Pharmacyclics LLC and Janssen Biotech, Inc. It is produced by Patient Power in partnership with The CLL Global Research Foundation, The US Oncology Network, Compass Oncology, Willamette Valley Cancer Institute and Research Center, and The Leukemia & Lymphoma Society (LLS).
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Transcript | Chronic Lymphocytic Leukemia Treatment Response: MRD Tests
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There’s something on the screen, MRD, which I’ve been schooled that it can mean two different things, minimal residual disease at like the micro, micro level or measurable residual disease.
Jeff Sharman, where does that come into play to understand—let’s say if somebody’s been previously treated, did we knock it back or is it rearing its head even at the micro level now and might we at some point need to do something again?
Right. So, at the technical level, MRD, minimal residual disease, is a testing technique that we can do that establishes very, very small amounts of CLL. The most commonly utilized test currently is this thing called flow cytometry and for the most part with good flow cytometry, you can determine if a patient has a threshold where out of 10,000 cells from their peripheral blood if one of them is CLL. So, it’s 10 to the minus fourth or 0.1 percent of their cells.
If you actually think about 0.1 percent, when somebody’s going to get treated and they’re coming in to get treated, we would normally expect their lymphocyte count to be maybe somewhere between somewhere between 70 percent to 95 percent of their cells in the peripheral blood or CLL. So, now, we’re talking about doing some sort of intervention and getting it to ideally less than 0.1 percent. So, you can see that we can get rid of a whole lot of CLL.
MRD is historically used kind of mostly in research studies, therapeutic studies where we’re trying to establish how effective a therapy is and we’ll say this regimen gives MRD negativity at a rate of 20 percent or this one gets it in 40 percent or 60 percent. So, it’s kind of a barometer within the field where we can sort of start to compare the effectiveness of different treatment regimens.
With a lot of the new drugs, ibrutinib (Imbruvica) in particular, this whole concept kind of got thrown out because with ibrutinib, you can oftentimes see the CLL for a long amount of time, yet the CLL is inactive. So, we were getting really into MRD with all the chemotherapy drugs. Ibrutinib came along and we said, “MRD doesn’t matter.”
Now, along comes venetoclax—I’m sure we’ll spend more time about it—which once again gets very good levels of MRD negativity. So, it’s something in the field that has waxed and waned with regards to how important it is. I find patients oftentimes may ask the Alices of the world, who are what I call web positive, might ask whether MRD is important. I would say it’s very context-dependent.