Development of CRISPR_SCD001, an Autologous Hematopoietic Stem Cell Gene Therapy for Sickle Cell Disease after CRISPR-Cas9 Mediated Correction.

Publication Year:

2026

Authors:

Mark DeWitt, Beatriz Campo-Fernandez, Sohini Roy, Alissa L W Kleinhenz, Alejandra Davila, Mallory Lennon, Jonnathan T Vu, Netravathi Krishnappa, Suzanne Said, Chin-Hong Tseng, So Hyun Park, Gang Bao, Wendy Magis, David I K Martin, Dario Boffelli, Stacia K Wyman, Donald B Kohn, Mark C Walters, Zulema Romero

PubMed ID:

42760781

Funding Grants:

Public Summary:

We developed CRISPR_SCD001, an autologous cellular therapy in which the pathogenic HBB sickle allele is corrected by CRISPR/Cas9-mediated homology-directed repair using a single-stranded oligodeoxyribonucleotide as DNA donor template. The Drug Product (DP) from Plerixafor-mobilized peripheral-blood CD34⁺ cells from sickle and healthy donors were used for: 1) pharmacodynamic assessments to interrogate therapeutic potential; 2) evaluation of genotoxicity; and 3) in vivo characterization by a non-GLP toxicology study in NBSGW mice. Large-scale DP lots yielded 89 ± 5 % CD34⁺ purity with 84 ± 6 % viability. Mean gene correction at HBB was 22 ± 4 % of alleles, with 51 ± 6 % of allelic disruption. Edited erythroid cultures produced 39 ± 5 % adult hemoglobin and 40 ± 6 % fetal hemoglobin, reducing sickle hemoglobin from 89% to 22 ± 6 %. In NBSGW mice, CRISPR_SCD001 engrafted robustly (59 ± 25%), maintained editing frequencies comparable to injected cells (~20% gene correction), showed polyclonal distribution of the edited cells, and no noteworthy treatment-related toxicity or pathologic evident were found by a blinded histopathology assessment. Our protocol generates a clinical-grade, cryopreserved CD34⁺ cell product that corrects the sickle mutation, restores anti-sickling hemoglobins, and meets pre-clinical safety criteria. These data support initiation of a first-in-human phase I trial of CRISPR_SCD001 for sickle patients presenting with severe pathology.

Scientific Abstract:

We developed CRISPR_SCD001, an autologous cellular therapy in which the pathogenic HBB sickle allele is corrected by CRISPR-Cas9-mediated homology-directed repair using a single-stranded oligodeoxyribonucleotide as DNA donor template. The Drug Product (DP) from Plerixafor-mobilized peripheral-blood CD34(+) cells from sickle and healthy donors were used for: 1) pharmacodynamic assessments to interrogate therapeutic potential; 2) evaluation of genotoxicity; and 3) in vivo characterization by a non-GLP toxicology study in NBSGW mice. Large-scale DP lots yielded 89 +/- 5 % CD34(+) purity with 84 +/- 6 % viability. Mean gene correction at HBB was 22 +/- 4 % of alleles, with 51 +/- 6 % of allelic disruption. Edited erythroid cultures produced 39 +/- 5 % adult hemoglobin and 40 +/- 6 % fetal hemoglobin, reducing sickle hemoglobin from 89% to 22 +/- 6 %. In NBSGW mice, CRISPR_SCD001 engrafted robustly (59 +/- 25%), maintained editing frequencies comparable to injected cells ( approximately 20% gene correction), showed polyclonal distribution of the edited cells, and no noteworthy treatment-related toxicity or pathologic evident were found by a blinded histopathology assessment. Our protocol generates a clinical-grade, cryopreserved CD34(+) cell product that corrects the sickle mutation, restores anti-sickling hemoglobins, and meets pre-clinical safety criteria, establishing a reproducible manufacturing process suitable for clinical translation. These data support initiation of a first-in-human phase I trial of CRISPR_SCD001 for sickle patients presenting with severe pathology.