[skissane]

There is active research on doing gene therapy without requiring chemotherapy (or radiation) first. It has been shown to work in mice, and they may eventually get it working in humans too. It would likely require a significant modification to these gene therapies though, since one approach is to alter the method of growing the stem cells to produce a significantly higher number, and then transplant that, with the hope that the transplanted edited cells outnumber and outnumber the original unedited ones. So very likely the FDA would treat that as a new therapy requiring a new approval process.

https://med.stanford.edu/news/all-news/2019/05/radiation-fre...

There is also ongoing research into immunotherapy for killing stem cells, as an alternative to the existing methods of chemotherapy and radiation. Potentially, immunotherapy could have significantly reduced secondary cancer risk.

https://jhoonline.biomedcentral.com/articles/10.1186/s13045-...