Clinical Trial

Disease: Relapsed of Refractory Acute Myeloid Leukaemia, AML, (NCT05662904)

Disease info:

Leukaemia is cancer of the white blood cells which are responsible for fighting infection. In leukaemia, the bone marrow produces abnormal levels of white blood cells. Acute myeloid leukaemia (AML) starts in the bone marrow but often quickly spreads into the bloodstream. AML sometimes spreads to other parts of the body such as the lymph nodes, liver, central nervous system and testicles. 

Commonly, AML develops from cells other than lymphocytes that would normally develop into white blood cells. The World Health Organization (WHO) divides AML into several subtypes based off genetic association. AML is also known as acute myelocytic leukaemia, acute myelogenous leukaemia, acute granulocytic leukaemia, and acute non-lymphocytic leukaemia.

Relapsed refers to when a patient has received active treatment, went off treatment and then the disease came back, whereas refractory refers to disease that is progressing despite active treatment.

The American Cancer Society estimates approximately 20,380 cases of AML will be diagnosed in the U.S. in 2023, and approximately 11,310 deaths. AML is predominantly found in adults and is one of the most common types of leukaemia in adults.
Official title:
Genetic Ablation of CD33 in Hematopoietic Stem Cells to Broaden the Therapeutic Index of CD33-directed Immunotherapy in Patients With Acute Myeloid Leukemia (AML)


Name: Tim Sauer, Dr. med.

Phone Number: +49 6221 56 38010




German Cancer Research Center


University Hospital Heidelberg

University Hospital Dresden


Dresden, Germany
University Hospital Dresden, Department of Medicine I, Dresden, Germany, 01307

Heidelberg, Germany
University Hospital Heidelberg, Internal Medicine V, Heidelberg, Germany, 69120

Study start:
Dec. 1, 2022
12 participants
Gene editing method:
Type of edit:
Gene knock-out
Delivery method:
Not disclosed - Ex-vivo
IND Enabling Pre-clinical
Phase I Safety
Phase II Safety and Dosing
Phase III Safety and Efficacy

Status: Not yet recruiting


CRISPR/Cas9-mediated inactivation of CD33 in hematopoietic stem cells (HSC) may broaden the therapeutic index of CD33-directed immunotherapy for patients with AML by rendering healthy hematopoietic stem and progenitor cells (HSPC) resistant to escalating doses and/or shorter dosing intervals of the CD33-specific antibody-drug conjugate (ADC) Gemtuzumab-ozogamicin (GO).

In this proof of concept trial, we will develop a platform for genome editing of CD34+ HSC and demonstrate the feasibility, safety and efficacy of this approach for targeted therapy of AML.

Upon implementation, the platform shall be used for innovative clinical trials in diverse types of cancer. Outside of leukemias, autologous HSC could be used to ease the procedure.

Patients with relapsed AML after allogeneic hematopoietic stem cell transplantation will be transplanted with CD33-deleted CD34+ HSC derived from the initially matched family donor.

Upon HSC engraftment, patients will be treated with escalating doses of the anti-CD33 antibodydrug conjugate Gemtuzumab-Ozogamicin (GO). A conditioning regimen containing GO (d-14, d-11, d-8),Fludarabine 30 mg/m2 (d-6 to d-3) and Melphalan 140mg/m2 (d-2) is used prior to transplantation.

The clinical trial will be conducted at two trial sites in the University Hospitals in Heidelberg and Dresden.

25 patients will be assessed for eligibility and 12 patients will be allocated into the trial.

Last updated: Dec. 30, 2023
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