CRISPR-Engineered Blood Stem Cells Open a New Frontier for Precision Cancer Immunotherapy

A clinical study published in Nature Medicine highlights the potential of genome engineering to transform hematologic cancer treatment through the development of CRISPR–Cas9-edited hematopoietic stem and progenitor cells (HSPCs) designed for high-risk acute myeloid leukemia (AML).

Patients with AML and myelodysplastic syndrome (MDS) often relapse after hematopoietic cell transplantation, while many targeted therapies are limited by damage to healthy cells that share the same therapeutic targets as cancer cells.

Trem-cel: Targeted CD33 Deletion

To address this challenge, researchers developed tremtelectogene empogeditemcel (trem-cel), a CRISPR-edited donor HSPC therapy in which the CD33 gene was disrupted. Since CD33 is expressed on both AML cells and normal myeloid cells, CD33 deletion creates a protective advantage for healthy donor-derived cells, allowing CD33-directed therapies to target leukemia while preserving normal blood formation.

In a multicenter Phase 1/2a trial, 30 patients with high-risk AML or MDS received trem-cel transplantation. All patients achieved neutrophil engraftment, with a median recovery time of 10 days, demonstrating rapid and durable hematopoietic reconstitution.

Following transplantation, patients received gemtuzumab ozogamicin (GO), a CD33-targeted therapy. The engineered graft enabled treatment while maintaining hematopoietic function, including long-term development of myeloid, B-cell, and natural killer (NK) cell populations.

Engineering the Immune System Beyond CAR-T

This study introduces a new paradigm in cellular medicine: rather than only engineering immune cells to attack cancer, researchers can also engineer healthy cells to withstand targeted therapies and create a selective advantage against malignant cells.

This approach could pave the way for next generation:

• Engineered hematopoietic stem cell therapies
• Advanced cellular immunotherapies
• Precision treatments for hematologic malignancies

By combining CRISPR genome editing with hematopoietic transplantation, researchers are moving toward a future where cellular therapies can be programmed not only to eliminate cancer, but also to protect healthy tissues during treatment.

Source: Nature Medicine, “CRISPR−Cas9 CD33-deleted allogeneic hematopoietic cell transplantation with gemtuzumab ozogamicin maintenance in AML: a phase 1/2 trial,” May 12, 2026.