From November 14th to 17th, 2024, the Cellular Therapy and Immunotherapy Conference (CTI) was grandly held in Hangzhou, China, gathering top experts, scholars, and industry leaders in the field of global cell therapy and immune therapy. The conference served not only as an international platform for academic exchange but also as an important window to showcase the latest scientific research and promote the development of the field. During the conference, "Hematology Frontier" specially invited Dr. Leo Luznik from Baylor College of Medicine,USA to share the latest progress of Bone Marrow Infiltrating T Cells (MITs) in the treatment of relapse after Allogeneic Hematopoietic Stem Cell Transplantation (HSCT). He revealed the potential and challenges of MITs in treating relapse after HSCT and looked forward to the future development direction of the field.

Hematology Frontier：What is the role of marrow infiltrating T cells in the treatment of relapse after allogeneic hematopoietic stem cell transplantation (HSCT)?

Dr. Leo Luznik：This is the early data or phase one/two study of a new cellular therapy trying to treat relapse post transplantation, which is a very challenging and difficult medical problem. So this is an innovative strategy. What we try to conduct , based on previous biological to understand can we use these cells to prevent relapse. And why do they work, or why did they fail, and how we can use them in a better way in the future.

Hematology Frontier：what unique advantages have marrow infiltrating T cells demonstrated compared to other therapies in treating relapse after HSCT?

Dr. Leo Luznik：One of the main challenges, despite the many good things of new cell therapies, are the cost. Did they acquire extensive gene modulation and growth, which carries substantial burden to the payers or the patients. While our idea was to develop something that is relatively inexpensive, allowing quick turnaround without much cost and without much regulatory oversight, because it does not require gene editing or gene therapy. We can provide it quicker to the patients, which, ultimately, if it ever works, can help patients outside of the more advanced or rich countries and payer systems.

Hematology Frontier：Are there differences in the effectiveness of marrow infiltrating T cells treatment among patients with different types of HSCT relapse? If so, what are the main aspects of these differences?

Dr. Leo Luznik：We usually divide relapses into early relapse and late relapse. Unfortunately, early relapse has the worst outcome because if you relapse early after transplant, just because of the biology and new technologies, we tested these only in patients who have a late relapse, meaning more than six months or a year post-transplant. versus there is a whole other question: can we use these cells to the early relapse? And can we also prevent relapse? I think these are interesting biological questions that we want to look next. This is the difference in what we have done in this study—we have focused on late relapse.

The first thing we are trying still to complete biological studies, because it’s always important when you do something, when you do it in a patient to understanding how it works biologically.The next question is how we can grow these cells better so we can achieve better product. And then it might even come to the question: do we need to do some additional modifications, even genetic modification, to make them as a more potent or more sustainable therapy? But this was just a very early phase I/II data to test some new concepts and learn about the biology in patients who are relapsing after hematopoietic transplantation.