How does treatment for acute lymphoblastic leukemia differ between children and adults?
First of all, children with ALL tend to have types of ALL that are more sensitive to chemotherapy. By that, I mean we're able to cure more children the first time around with treatment. Fewer children benefit from a stem cell transplant because the risk of relapse with standard therapy is lower, and children are often able to tolerate chemotherapy more effectively than older adults.
Now, as I said in children in general, we're starting off with either 3 or 4 drugs as part of induction therapy, followed by blocks of treatment such as consolidation and maintenance, in order to ensure that the person is able to achieve the deepest possible remission and to maintain that, and adults and younger adults in particular. We often are using some of the same principles that we've learned from the treatment of children.
A number of years ago, a colleague of mine, Wendy Stark, who is at the University of Chicago, published a landmark analysis comparing patients treated by pediatric versus adult oncologists in the United States and a number of groups from around the world did the same on the same time. And we determined that, in general, using a pediatric treatment approach, that about 15% more patients were able to achieve long term survival.
A pediatric approach consists of using intensified and more extended treatment with drugs that are less blood count suppressive such as vincristine, steroids, and asparaginase. Whereas more conventional adult regimens use treatment paradigms that more and more blood count suppress. Using higher doses of class of drugs like cytarabine and anthracycline, for example.
Now, all of these things are important tools in the treatment of adults with ALL. And a so-called pediatric regimen is not right for everyone, but for adults up to the age of 50 or 60 years old, depending on the particular regimen. We're often able to incorporate at least some elements of those pediatric inspired regimens.
For patients that have Philadelphia chromosome negative ALL either B or T cell ALL that lacks the the Philadelphia chromosome. The goal of treatment in children and adults with ALL is cure, but the way that we get there might be a little bit different. In adults who are older, like, let's say, for example, adults who are over 60 with Philadelphia chromosome negative acute lymphoblastic leukemia. Oftentimes will use dose reduced chemotherapy regimens.
And we've been trying to leverage some of the strengths of these immunotherapies, including inotuzumab, the antibody drug conjugate, blinatumomab, the bispecific T-cell engager for example. In order to enhance the activity of these regimens without adding toxicity from intense blood count suppression. For this group of patients.
As patients get older, there's also a higher risk of having Philadelphia chromosome positive acute lymphoblastic leukemia. And for patients who are older with Ph-positive ALL in particular, we try to avoid the addition of intensive chemotherapy because these patients are able to do very well quite often with either just steroids in combination with a targeted therapy or with immune therapy such as blinatumomab in combination with their oral targeted therapies.
In fact, those approaches that are sparing chemotherapy in Philadelphia chromosome positive ALL are becoming so effective that we're even starting to use them in some younger adults as well.
However, broadly, as patients are older, we do need to deintensify their chemotherapy, in order to reduce the risks to them, both of infections as well as organ toxicities. And one goal in the field is to try to decrease the intensity, of a therapy without decreasing the effectiveness of the regimen. And that includes both using some of these novel immunotherapies that we have available now, as well as investigating a number of other targeted treatments or immunotherapy treatments, to help these patients further to have better outcomes.