BioTech IP Review

• Journal: Cell
• Publication Date: October 12, 2023 (online early release dates around October 3, 2023)
• Volume & Issue: Volume 186, Issue 21 (Oct 12, 2023)
• DOI: 10.1016/j.cell.2023.08.041
• Authors: Connor A. Tsuchida, Nadav Brandes, Raymund Bueno, Marena Trinidad, Thomas Mazumder, Bingfei Yu, Byungjin Hwang, Christopher Chang, Jamin Liu, Yang Sun, Caitlin R. Hopkins, et al., including Carl H. June and Jennifer Doudna among others

What it Covers

This Cell study uncovered a previously under‑recognized safety concern in CRISPR‑Cas9 genome editing as applied to human T cell therapies, a leading class of engineered immunotherapies for cancer and other diseases:

• Chromosome loss: The researchers found that CRISPR‑Cas9 editing in primary human T cells can cause unintended loss of the entire targeted chromosome or large chromosome segments, a form of genomic instability that could pose safety issues for clinical use. This loss was shown to occur across multiple target sites in the genome, not just at a single locus, and was measurable weeks after editing in culture.
• Clinical relevance: Such chromosome loss was also detectable in preclinical CAR‑T cells (T cells engineered to express chimeric antigen receptors), meaning the phenomenon is relevant to therapies that are already being tested or used clinically.
• Mitigation strategy: Importantly, the authors demonstrated that modifying the order and conditions of the CRISPR editing protocol — specifically altering the timing of cell activation relative to Cas9 delivery — substantially reduced the incidence of chromosome loss while preserving editing efficiency. They also noted that higher expression of the DNA damage response protein p53 correlated with protection from chromosome loss, suggesting mechanistic insight.

Why It’s Important

• Clinical gene editing safety: As CRISPR‑based therapies (including CAR‑T, TCR‑engineered cells, and other modified cell types) move rapidly into clinical use, understanding and mitigating unintended genomic consequences is critical for safety and regulatory approval.
• Real‑world impact: This work directly informs manufacturing practices for cell‑based gene therapies, offering actionable strategies to improve genome integrity in engineered T cells destined for patients.
• Translational relevance: It bridges basic CRISPR biology with clinical process optimization, moving beyond proof‑of‑principle editing to address barriers to safe therapeutic application.

In short: This Cell paper was a major contribution to biotechnology and therapeutic genome editing, revealing a genome‑wide safety challenge in CRISPR‑engineered T cells and proposing a practical way to mitigate it — a crucial insight for advancing next‑generation cell therapies.