Development of gene therapy and genome editing strategies to treat adenosine deaminase 2 deficiency

Project Information

DADA2GT

Grant agreement ID: 841780

DOI

10.3030/841780

Project closed

EC signature date 11 April 2019

Start date 1 June 2019

End date 31 May 2021

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 183 473,28

EU contribution

€ 183 473,28

Coordinated by

OSPEDALE SAN RAFFAELE SRL
Italy

Periodic Reporting for period 1 - DADA2GT (Development of gene therapy and genome editing strategies to treat adenosine deaminase 2 deficiency)

Reporting period: 2019-06-01 to 2021-05-31

Summary of the context and overall objectives of the project

Adenosine deaminase 2 deficiency (DADA2) is a rare inherited disorder caused by autosomal recessive mutations in the ADA2 gene. Clinical manifestations include early-onset lacunar strokes, vasculitis/vasculopathy, systemic inflammation, immunodeficiency, and hematologic defects. Conventional therapies do not offer a definitive treatment modality and often carry a high burden on social costs and quality of life. Anti-TNF therapy reduces strokes and systemic inflammation but does not correct hematopoietic alterations. Allogeneic hematopoietic stem-progenitor cell (HSPC) transplantation can ameliorate most disease manifestations, but patients are at risk for severe complications, including graft versus host disease, veno-occlusive disease, organ toxicity, and infections. Therefore, the development of targeted therapeutical approaches for DADA2 is urgently needed. Being DADA2 a recessive monogenic disease, we envisioned a gene transfer approach mediated by lentiviral vectors (LV) in patients’ HSPCs as a curative option for the future. The overall objective of the DADA2GT project was to develop an LV-mediated HSPC-based gene therapy approach for DADA2. Our results support the implementation of HSPC gene therapy for DADA2.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We generated a lentiviral vector (LV) encoding human ADA2 to genetically correct HSPCs and evaluated the feasibility, efficacy, and toxicity of HSPC gene therapy for DADA2. Lentiviral transduction allowed efficient delivery of the functional ADA2 enzyme into HSPCs of healthy donors. Supranormal ADA2 expression in human and mouse HSPCs did not affect their multipotency and engraftment potential in vivo. Moreover, LV-ADA2 induced stable ADA2 expression and corrected the enzymatic defect in HSPCs derived from DADA2 patients. Patients’ HSPCs re-expressing ADA2 retained their ability to differentiate into erythroid and myeloid cells. Patients’ macrophages exhibited a skewed differentiation toward the M1 pro-inflammatory phenotype characterized by increased IL-6 and TNF secretion than healthy donors’ M1 macrophages. LV-mediated correction of ADA2 in patients’ macrophages led to a complete rescue of the excessive inflammatory cytokine production. ADA2 enzymatic activity was required for correction of the amplified M1 macrophage response. The successful completion of the project showed the feasibility and efficacy of the HSPC gene therapy to treat patients affected by DADA2, which is instrumental in bringing the advanced therapy medicinal product forward to clinical development. In terms of exploitation, the main results achieved through the DADA2GT project include the new orphan drug designation for DADA2, which will facilitate alliance with industry and EU market approval. DADA2GT discoveries were shared with scientists worldwide via presentations in international scientific conferences (e.g. ESGCT, ASGCT, ESID, and DADA2 Conference) and a publication in an international peer-reviewed journal.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The DADA2GT project has progressed beyond the state of the art as it was possible to achieve important new discoveries. In relation to the project, we demonstrated, for the first time, that:
- LV-ADA2 able to correct the enzymatic defect in HSPCs and macrophages of patients with DADA2;
- ADA2 over-expression did not impact the engraftment and multilineage potential of in healthy donors’ HSPCs;
- ADA2 reconstitution in patients’ macrophages prevents excessive inflammation.
These new findings supported the application for the new orphan drug designation for DADA2, which received approval by EMA in July 2021. The orphan drug designation for DADA2 is essential because it will stimulate research and development in the sector of orphan drugs and facilitate the clinical development of gene therapy for DADA2. The incentives assured by the EU authorities will be instrumental in attracting health and biotechnology industries to speed up future clinical studies.
The DADA2GT project also contributed to raise the overall awareness of DADA2 in many typologies of subjects, including academic researchers, clinicians, students, patients’ associations, no-profit organizations, and the general public in order to support early and accurate diagnosis.

Summary Image