In March 2017, an early CRISPR-based clinical study in the United States progressed from preclinical development into a regulated, first-in-human setting. Led by researchers at the University of Pennsylvania, the work explored whether CRISPR‑Cas9 could be used to edit a patient’s own T cells to improve immune recognition of cancer.

Study focus

The study enrolled patients with advanced malignancies, including melanoma, sarcoma, and multiple myeloma. CRISPR‑Cas9 was used to make targeted changes to specific genes in harvested T cells, with the intent of strengthening anti-tumour activity, an approach aligned with established principles of adoptive cell therapy and immunotherapy.

Process (high level)

• T cells were collected from the patient.
• Selected genes were edited ex vivo using CRISPR‑Cas9.
• Edited cells were expanded under controlled laboratory conditions.
• The modified cells were reinfused into the patient.

What the trial was designed to test

As an early-phase investigation, the primary objective was safety and feasibility, whether gene-edited cells could be manufactured reliably, administered as intended, and monitored without unacceptable adverse effects. Subsequent reporting indicated that CRISPR-edited cells could be infused and function in patients, supporting the practical viability of the approach.

Why this mattered

While earlier experimental uses of CRISPR in humans had been reported outside the United States, this study represented a notable milestone for clinical translation within a US regulatory framework. It helped establish a path for gene editing to move from laboratory capability to controlled clinical application.

Broader direction

Since 2017, CRISPR-based therapeutic development has broadened beyond oncology into inherited and haematological conditions, including sickle cell disease, inherited forms of blindness, and other genetic disorders.