Huidong Wang
Analyst · Barclays
And congrats on the -- all the program progress. So I have two questions regarding the UCART22, alemtuzumab cohort. So the first question is more the biology question for André. So just wondering what is your view on the immune system? How much residue immune system we need to maintain in order to have a good balance of, say, toxicity and the persistence of a foreign CAR-T cells? And the second question is regarding the alemtuzumab cohort. Why this additional cohort? And why now? Just wondering do you see Allogene's data? Will you use the lower dose?
André Choulika: Well, thank you very much, Gena, for these excellent questions, by the way. So to answer your first question, it's extremely difficult to know exactly what is the ideal window for a better duration for a CAR-T treatment today. It's very interesting because there are like a series of different way to tackle this. And within 2020, we'll have plenty of data that will be coming, either from us or a partner, Servier, or Allogene, but also from other companies, such as Precision Biosciences or others, using, for example, an approach where [indiscernible] beta-2 microglobulin, et cetera. So there are like series of way to do this, and all these data are going to flow in. What we can look at today is essentially the data that has been published, either by autologous CAR-Ts and that shows that there is like clearly no correlation between the duration of the therapy and the persistence of the CAR itself. So there is no clear correlation between the two. What is the best outcome, most of the time, is the deepness and of the activity of the CAR itself in a short period of time or more like the killing potential and the expansion potential of the CAR that is injected, that would be directly correlated to the duration of the therapy itself more than the persistence of the CAR for a long period of time. Nevertheless, also, it's something that we'd like to investigate. We've seen the data of -- that has been obtained with UCART19 that we started, but has been pursued by Servier and Allogene currently, that are using alemtuzumab, was very interesting data, and we think that this approach that we created is very interesting. We decided to have a very deep comparative study in there and our plan during this year is trying to tune up our way to administer this type of therapy to the patient in the best way in order to confirm the way to administer this during the expansion phase that would happen next year. And of course, the window of lymphodepletion, we believe, should be around like over 20 days and should be around a month. But if you want to implement, for example, a re-dosing strategy, it could be interesting eventually to expand this maybe to a couple of weeks more. And we're excited about that. On the other hand, maintaining also the lymphodepletion during this period could be done essentially by, of course, like classical cyclo/fluda, but also potentially by administering other type of drugs or maybe also modifying the CAR itself. And answering totally, this question is not totally very easy. It depends on the targets. So 22, for example, or 19, just hit B cells, 123, go after myeloid progenitors. So could expand the time of the window larger than we expected because the myeloid progenitors won't be able to rebuild, for example, an immune response. CS1 is present on T-cells, B-cells, NK cells, et cetera. So they might deepen the lymphodepletion while expanding. So all these questions we need to answer, and we're still in the first like cohort for 22, and it's currently like we would like to move forward with this. And as we would like to move forward with this, we decided to file this amendment right now, but it should take place probably second half this year in order to be able to make a comparative study that could give us more insights on the way to precondition the patient, the best way to do it on the safety and efficacy side. So there is a leveling behind this that should be done. And as we have all the potential to do this because we, like CD22 is -- like UCART22 is CD52-enabled, so it's like resistant to alemtuzumab. This study -- parallel study is between like a cohort with or cohort without would give us very, very insightful data and would allow us to move forward with probably the best dosing strategy for the expansion.