Needs more editing –
The safety results are promising, the cancer outcomes less so.
Sequencing of the DNA from engineered cells showed that there were some off-target edits, but the rates varied among the genes. This suggests there’s some work left to do in terms of designing the gene-editing constructs. There were also some large chromosomal rearrangements in response to the editing. The most common was a single deletion that took out both T cell receptors, which was fine for the purposes of this work. Other large rearrangements were present, but they tended to drop out of the population of engineered cells over time, possibly do to detrimental effects on their growth.
With that level of off-target effects considered an acceptable risk, the researchers then infused the engineered cells into three of the patients .
Still, from the perspective of the goal of this trial — basic safety — the trial was a success and will likely lead to Further safety tests on a larger population. These will likely be able to leverage advances in gene editing that have occurred since the first trial was designed and involve enough patients that we’re likely to be able to detect a broader spectrum of responses to the therapy. It’s possible that larger trials could identify a sub-population of patients where this therapy works better or provide hints of how to combine it with additional therapies that improve its effectiveness.
Science, . DOI: . 1866 / science.aba (
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