Announcer: One of the most significant developments in cancer treatment today is the use of targeted therapies. It has now become important in the treatment of non-Hodgkin's lymphoma.
Stephanie Ann Gregory, MD: A targeted agent is something that actually goes in and hits a cancer cell and preserves the normal cells.
Leo I. Gordon, MD: Rituxan is the major targeted therapy for non-Hodgkin's lymhoma. It targets the CD20 antigen on the surface of B-cells.
Announcer: In targeting malignant lymphoma cells, Rituxan is a non-radioactive antibody. It's used alone or combination with the standard of care for lymphoma-chemotherapy.
Leo I. Gordon, MD: There are some immediate side effects with Rituxan. People can get fevers. They can get a tickling sensation in their throat. They can get short of breath. So you need to infuse it fairly slowly.
Announcer: But the newest targeted therapy, radioimmunotherapy, provides the added benefit of radiation.
Robert O. Dillman, MD, FACP: Radioimmunotherapy at the present time consists of monoclonal antibodies that have radioisotopes attached to them so that you can target the radiation to whatever the antibody binds to.
Announcer: There are two drugs currently used in radioimmunotherapy, Zevalin and Bexxar. Each uses different radioisotopes with unique characteristics.
Leo I. Gordon, MD: Zevalin utilizes radioactive yttrium and has a very short half-life. It's short half life mean that it can be given as an outpatient. There's lots of studies now showing that it's fairly safe to give, safe for the patient and especially also safe for family members and health care workers. Bexxar utilizes I-131. The advantage of I-131 linked to antibody is that you can get a pretty good sense of where the radioactivity is going just from one dose. The downside of I-131 is that it's got a fairly long half-life so that patients, at least in many states around the country still need to be hospitalized.
Announcer: Many doctors today are considering how to choose between the different targeted therapies, and where to position them within a treatment regimen.
Robert O. Dillman, MD, FACP: Is it best to use Rituxan by itself? Is it best to use it in combination with chemotherapy? Is it best to use Rituxan first, then chemotherapy? Chemotherapy first, then Rituxan? And we don't really have clear answers on that. In terms of Rituxan vs. the radioimmunotherapy, I think at the present time you definitely would always want to pick Rituxan first. The reason for that is its safety profile seems to be superb. It's a very well tolerated agent and some patients get remarkably good responses with it that last for years and years.
Announcer: In selecting a treatment, particularly radioimmunotherapy, doctors must consider which patients are most appropriate.
Robert O. Dillman, MD, FACP: If somebody fails Rituxan, radioimmunotherapy is an option. The ideal patient, however is someone who previously has responded to Rituxan and the response has gone away rather than somebody who just got Rituxan.
Stephanie Ann Gregory, MD: The criteria for delivering radioimmunotherapy is essentially that you must not have a bone marrow that has involvement with lymphoma of more than 25 percent of the bone marrow.
Leo I. Gordon, MD: When the radioactivity gets into the marrow in large amounts, as it would when you have the marrow extensively involved with lymphoma, then the toxicity is going to be greater.
Stephanie Ann Gregory, MD: Patients are also not candidates for radioimmunotherapy if they have had a stem-cell transplant.
Announcer: For those who have used radioimmunotherapy, doctors have found improved response rates.
Stephanie Ann Gregory, MD: The response to Rituximab the naked antibody has been about 50 percent in patients who have relapsed non-Hodgkin's lymphoma of the low-grade variety. Of those patients, very few of them are what we refer to as complete remissions. Radioimmunotherapy has an overall response in general of about 70 percent compared to the 50 percent with Rituximab and the complete remissions are about 30 percent compared to very low numbers with the naked antibody.
Announcer: Chemotherapy remains a standard of treatment for many types of lymphomas. But radioimmunotherapy can offer several advantages.
Stephanie Ann Gregory, MD: Chemotherapy essentially hits all cells especially the rapidly dividing cells, so you do get toxicities with regular chemotherapy that you don't get with targeted therapy.
Russell Schilder, MD: Patients don't lose their hair, first of all, in radioimmunotherapy. There's much less nausea and vomiting, though that obviously varies with the type of chemotherapy. Even though the counts can go low with both forms of treatment, there's no stomatitis with radioimmunotherapy, no sore mouth. The risk of fever and neutropenic fever is much lower because we're not being invaded by the bacteria of the gut.
Announcer: Though few, there are some side effects with radioimmunotherapy.
Leo I. Gordon, MD: The immediate side effects are predominantly a drop in blood counts. We usually see the major drop in count not occurring for four, five even six weeks after treatment, and on average I think the data would show that the counts are low for a period or two, maybe even three weeks, and then they return to normal. I think radioimmunotherapy has a distinct advantage over traditional therapies in that it's given basically one time. The treatment course takes two weeks. On week 1, day 1 patients receive the tracer dose so that so that you can determine if the radioactivity is going to normal organs. One week later they receive the treatment dose, and that's the end of the treatment.
Announcer: There are still many questions about the possible range of uses for radioimmunotherapy.
Robert O. Dillman, MD, FACP: One of the first question many medical oncologists ask is, "Can you even give other treatment after somebody has had radioimmunotherapy because of the concern about what it might do to the bone marrow cells, especially?" And it looks like from the results so far that yes, you can. A lot of patients have gotten other treatment after having had radioimmunotherapy.
Russell Schilder, MD: It's not a straightforward issue of whether or not you can give radioimmunotherapy in combination with other therapies.
Robert O. Dillman, MD, FACP: You can give successive targeted therapies but we don't have enough information right now to guide us on exactly how frequently repeated radioimmunotherapy should be given.
Announcer: As doctors continue to study and utilize targeted therapies, there is growing enthusiasm over the variety of options that will soon become available for lymphoma treatment.
Russell Schilder, MD: This is an exciting time for lymphoma treatment. We're going to probably soon have cocktails of antibodies. Vaccines are an active area of research. And how to combine all of that with each other and chemotherapy gives patients a lot of options.
Robert O. Dillman, MD, FACP: It wouldn't surprise me if within about a decade that we primarily are using unlabeled antibodies and antibody targeted treatments-and much, much less use of the nonspecific chemotherapy that we currently use.
Stephanie Ann Gregory, MD: A targeted agent is something that actually goes in and hits a cancer cell and preserves the normal cells.
Leo I. Gordon, MD: Rituxan is the major targeted therapy for non-Hodgkin's lymhoma. It targets the CD20 antigen on the surface of B-cells.
Announcer: In targeting malignant lymphoma cells, Rituxan is a non-radioactive antibody. It's used alone or combination with the standard of care for lymphoma-chemotherapy.
Leo I. Gordon, MD: There are some immediate side effects with Rituxan. People can get fevers. They can get a tickling sensation in their throat. They can get short of breath. So you need to infuse it fairly slowly.
Announcer: But the newest targeted therapy, radioimmunotherapy, provides the added benefit of radiation.
Robert O. Dillman, MD, FACP: Radioimmunotherapy at the present time consists of monoclonal antibodies that have radioisotopes attached to them so that you can target the radiation to whatever the antibody binds to.
Announcer: There are two drugs currently used in radioimmunotherapy, Zevalin and Bexxar. Each uses different radioisotopes with unique characteristics.
Leo I. Gordon, MD: Zevalin utilizes radioactive yttrium and has a very short half-life. It's short half life mean that it can be given as an outpatient. There's lots of studies now showing that it's fairly safe to give, safe for the patient and especially also safe for family members and health care workers. Bexxar utilizes I-131. The advantage of I-131 linked to antibody is that you can get a pretty good sense of where the radioactivity is going just from one dose. The downside of I-131 is that it's got a fairly long half-life so that patients, at least in many states around the country still need to be hospitalized.
Announcer: Many doctors today are considering how to choose between the different targeted therapies, and where to position them within a treatment regimen.
Robert O. Dillman, MD, FACP: Is it best to use Rituxan by itself? Is it best to use it in combination with chemotherapy? Is it best to use Rituxan first, then chemotherapy? Chemotherapy first, then Rituxan? And we don't really have clear answers on that. In terms of Rituxan vs. the radioimmunotherapy, I think at the present time you definitely would always want to pick Rituxan first. The reason for that is its safety profile seems to be superb. It's a very well tolerated agent and some patients get remarkably good responses with it that last for years and years.
Announcer: In selecting a treatment, particularly radioimmunotherapy, doctors must consider which patients are most appropriate.
Robert O. Dillman, MD, FACP: If somebody fails Rituxan, radioimmunotherapy is an option. The ideal patient, however is someone who previously has responded to Rituxan and the response has gone away rather than somebody who just got Rituxan.
Stephanie Ann Gregory, MD: The criteria for delivering radioimmunotherapy is essentially that you must not have a bone marrow that has involvement with lymphoma of more than 25 percent of the bone marrow.
Leo I. Gordon, MD: When the radioactivity gets into the marrow in large amounts, as it would when you have the marrow extensively involved with lymphoma, then the toxicity is going to be greater.
Stephanie Ann Gregory, MD: Patients are also not candidates for radioimmunotherapy if they have had a stem-cell transplant.
Announcer: For those who have used radioimmunotherapy, doctors have found improved response rates.
Stephanie Ann Gregory, MD: The response to Rituximab the naked antibody has been about 50 percent in patients who have relapsed non-Hodgkin's lymphoma of the low-grade variety. Of those patients, very few of them are what we refer to as complete remissions. Radioimmunotherapy has an overall response in general of about 70 percent compared to the 50 percent with Rituximab and the complete remissions are about 30 percent compared to very low numbers with the naked antibody.
Announcer: Chemotherapy remains a standard of treatment for many types of lymphomas. But radioimmunotherapy can offer several advantages.
Stephanie Ann Gregory, MD: Chemotherapy essentially hits all cells especially the rapidly dividing cells, so you do get toxicities with regular chemotherapy that you don't get with targeted therapy.
Russell Schilder, MD: Patients don't lose their hair, first of all, in radioimmunotherapy. There's much less nausea and vomiting, though that obviously varies with the type of chemotherapy. Even though the counts can go low with both forms of treatment, there's no stomatitis with radioimmunotherapy, no sore mouth. The risk of fever and neutropenic fever is much lower because we're not being invaded by the bacteria of the gut.
Announcer: Though few, there are some side effects with radioimmunotherapy.
Leo I. Gordon, MD: The immediate side effects are predominantly a drop in blood counts. We usually see the major drop in count not occurring for four, five even six weeks after treatment, and on average I think the data would show that the counts are low for a period or two, maybe even three weeks, and then they return to normal. I think radioimmunotherapy has a distinct advantage over traditional therapies in that it's given basically one time. The treatment course takes two weeks. On week 1, day 1 patients receive the tracer dose so that so that you can determine if the radioactivity is going to normal organs. One week later they receive the treatment dose, and that's the end of the treatment.
Announcer: There are still many questions about the possible range of uses for radioimmunotherapy.
Robert O. Dillman, MD, FACP: One of the first question many medical oncologists ask is, "Can you even give other treatment after somebody has had radioimmunotherapy because of the concern about what it might do to the bone marrow cells, especially?" And it looks like from the results so far that yes, you can. A lot of patients have gotten other treatment after having had radioimmunotherapy.
Russell Schilder, MD: It's not a straightforward issue of whether or not you can give radioimmunotherapy in combination with other therapies.
Robert O. Dillman, MD, FACP: You can give successive targeted therapies but we don't have enough information right now to guide us on exactly how frequently repeated radioimmunotherapy should be given.
Announcer: As doctors continue to study and utilize targeted therapies, there is growing enthusiasm over the variety of options that will soon become available for lymphoma treatment.
Russell Schilder, MD: This is an exciting time for lymphoma treatment. We're going to probably soon have cocktails of antibodies. Vaccines are an active area of research. And how to combine all of that with each other and chemotherapy gives patients a lot of options.
Robert O. Dillman, MD, FACP: It wouldn't surprise me if within about a decade that we primarily are using unlabeled antibodies and antibody targeted treatments-and much, much less use of the nonspecific chemotherapy that we currently use.