"Custom" in that this therapy was designed AFTER a specific patient showed a need, and then given to _that_ patient. In most every other context a particular class of disease is known, a drug designed, and then patients sought that have that disease that matches the purpose of the drug.
What's intriguing is not the 'custom' part, but the speed part (which permits it to be custom). Part of what makes CRISPR so powerful is that it can easily be 'adjusted' to work on different sequences based on a quick (DNA) string change - a day or two. Prior custom protein engineering would take minimum of months at full speed to 'adjust'.
That ease of manipulating DNA strings to enable rapid turnaround is similar to the difference between old-school protein based vaccines and the mRNA based vaccines. When you're manipulating 'source code' nucleic acid sequences you can move very quickly compared to manipulating the 'compiled' protein.
What's intriguing is not the 'custom' part, but the speed part (which permits it to be custom). Part of what makes CRISPR so powerful is that it can easily be 'adjusted' to work on different sequences based on a quick (DNA) string change - a day or two. Prior custom protein engineering would take minimum of months at full speed to 'adjust'.
That ease of manipulating DNA strings to enable rapid turnaround is similar to the difference between old-school protein based vaccines and the mRNA based vaccines. When you're manipulating 'source code' nucleic acid sequences you can move very quickly compared to manipulating the 'compiled' protein.