2022 SHS Professor Liu Qiqi: Application status and development prospects of hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) has been developed for nearly 70 years, and although new drugs in the field of blood diseases have emerged in recent years, HSCT is still irreplaceable
in the field of blood diseases.
In recent years, the number of HSCTs in China has increased year by year, which means that HSCT still has great room for
development.
At the "2022 Suzhou Hematology Summit and National Continuing Medical Education Class" held in Suzhou on October 7-9, 2022, Professor Liu Qiqi of Nanfang Hospital of Southern Medical University was specially invited to be interviewed to introduce the application status and development prospects
of HSCT.

HSCT has been widely used worldwide, and with the continuous advancement of transplantation technology, the indications for HSCT have been further broadened
.
Can you briefly talk about the current status of HSCT in blood diseases?

HSCT began to be used in clinical practice in the 50s of the last century, and after the 70s of the last century, with the discovery of HLA and the progress of supportive treatment, HSCT has developed
rapidly.
However, the lack of donor sources limits the widespread application of HSCT, and the emergence of haploid HSCT (haplo-HSCT) solves the problem of
limited donor sources.
HSCT is currently not only used in hematological diseases, but also in immunodeficiency-related diseases
.
AIDS is also one of the diseases of high global concern, and studies have shown that AIDS patients with hematological malignancies have achieved long-term AIDS remission
after receiving HSCT.
Although HSCT may have more side effects than cellular immunotherapy (such as CAR-T), so far CAR-T has not been able to completely replace HSCT as a "cure" treatment, and HSCT is still the only "cure" for
hematological diseases and some non-hematological diseases that can be treated with HSCT.

Medical Pulse: Because the heart, liver, kidney, and lung functions of elderly patients are decreasing year by year, it is difficult to tolerate HSCT and postoperative complications
.
With the development of medical technology, the proportion of elderly patients transplanted is increasing
year by year.
Can you please elaborate on the current situation of HSCT in elderly patients in China? What are the main problems and difficulties?

At present, China's HSCT technology is at the forefront of the world, but the proportion of elderly patients receiving HSCT in China is relatively low, and there is still a certain gap
compared with European and American countries.
There are two main reasons for this gap, one of which is the insufficient
understanding of HSCT tolerance in elderly patients in China.
Second, China's overall economic situation is poor compared with European and American countries, and the more complications after HSCT in elderly patients lead to an increase in HSCT-related costs, making the number of elderly patients who choose HSCT small
.
In recent years, the proportion of elderly patients with hematological diseases in China has gradually increased, and HSCT in elderly patients has also progressed
.
At present, judging whether elderly patients can undergo HSCT is not limited to the patient's physiological age, but also evaluates the patient's organ function, and decides whether to perform HSCT
based on the patient's functional age.
In addition, with the development of HSCT, the treatment of HSCT-related complications, the use of low-toxicity drugs in HSCT pretreatment, and the application of reduced-dose pretreatment in elderly patients have developed
.
In the future, the proportion of elderly patients receiving HSCT will increase
year by year.

At present, CAR-T cell therapy is in the ascendant, what are the advantages and disadvantages of acute lymphoblastic leukemia (ALL), allogeneic hematopoietic stem cell transplantation (allo-HSCT) and CAR-T cell therapy?

After nearly 70 years of development, HSCT has become an effective means to
"cure" hematological malignancies.
CAR-T has only been widely used in clinical practice in the past 5 years and has shown good prospects in hematological malignancies, but there is a lack of relevant data to prove that CAR-T can "cure" hematological malignancies
.
It is believed that CAR-T cell therapy will be improved in the future and show better results
in the treatment of hematological malignancies.
At present, it is impossible to distinguish which is superior and inferior, for different groups of people, choose different treatment methods, CAR-T and HSCT have their own advantages
.

Yimaitong: In the field of ALL, the combined application of allo-HSCT and CAR-T cell therapy is still being explored, can you share the latest progress in this regard?

At present, the discussion of allo-HSCT and CAR-T treatment for ALL patients mainly focuses on two aspects
.
Pre-transplant MRD-positive patients have a higher
rate of recurrence after allo-HSCT.
At present, relevant international studies have explored how to improve the efficacy of allo-HSCT in MRD-positive patients before transplantation, and found that sequential allo-HSCT after using CAR-T to clear MRD before transplantation can reduce the recurrence
of allo-HSCT in MRD-positive patients.
On the other hand, CAR-T therapy for patients with relapse after allo-HSCT is better than traditional chemotherapy
in terms of response rate and survival time.
However, most of these patients will eventually relapse, indicating that the long-term efficacy of CAR-T still needs to be improved
.
For patients at high risk of recurrence after transplantation, can CAR-T be used to prevent recurrence after allo-HSCT? Regarding the exploration of this problem, the relevant data at home and abroad are not perfect, which is also one of the future exploration directions of
ALL treatment.

Professor Liu Qiqi

• Dean of the Institute of Hematology and Director of the Institute of Hematology, Southern Medical University

• Director of the Department of Hematology, Professor, Chief Physician and Doctoral Supervisor of Nanfang Hospital

• Member of the Asia-Pacific Society of Hematology

• Vice Chairman of the Hematology Branch of the Chinese Medical Association

• Head of the Infectious Disease Group of the Hematology Branch of the Chinese Medical Association

• Vice President of Hematology Branch of Chinese Geriatrics Association

• Vice Chairman of the Cell Research and Therapy Branch of the Chinese Research Hospital Association

• Member of the Standing Committee of Hematologist Branch of Chinese Medical Doctor Association

• Chairman of the Hematology Branch of Guangdong Medical Association and Vice Chairman of the Society of Cell Therapy

• Chief expert of hematological oncology in Guangdong Province