I took blinatumomab in 2015 (in my late 20s). It literally saved my life. However, the risks of blinatumomab were seen as much riskier than chemotherapy. Most notably, blinatumomab has a significant risk of triggering a cytokine storm[0], a frequently-fatal immune reaction cascade. When starting a cycle of blinatumomab, the hospital required that I be inpatient for 7 days and they checked my vitals at least once every two hours. (This was _miserable_ for my sleep schedule, which is already a mess when in the hospital.) My regimen was 7 days in the hospital, then 21 days at home constantly connected to the pump, then 7 days of recovery time before starting another cycle.

At the time I took blinatumomab, I had already had unsuccessful treatments with two different chemo regimens. At the hospital system I was at, at least one failed chemo regimen was a pre-requisite for blinatumomab, as it was only indicated for "refractory" or "recurrent" cancers. I assume this is more related to the chance of acute death and (at the time) relative newness of blinatumomab compared to established chemotherapy regimens. (B-cell ALL is sadly very common in children, but this fortunately means that there is a LOT of funding research into the disease.)

After going through 3 one-month cycles of blinatumomab, it was becoming less effective, but I was able to line up a allogenic stem cell transplant which has (knock on a thousand woods) kept me clean for the 8 years since.

[0] https://en.wikipedia.org/wiki/Cytokine_storm