Blinatumomab or inotuzumab ozogamicin as a bridge to stem cell transplant in relapsed/refractory B-cell acute lymphoblastic leukemia

This study aimed to evaluate the use of blinatumomab Blincyto; B) or inotuzumab ozogamicin (Besponsa; IO) as a bridge to stem cell transplant for patients with relapsed or refractory (unresponsive) B-cell acute lymphocytic leukemia (B-ALL). 

This study concluded that both treatments are safe and effective as a bridge-to-transplantation in these patients. 

Blinatumomab (B) and inotuzumab ozogamicin (IO) are both immunotherapies used as a salvage treatment for relapsed/refractory (r/r) ALL. A salvage treatment is one which is given after the cancer does not respond to standard treatment or comes back. It was unknown if B and IO are safe and effective as a bridge to stem cell transplantation (SCT) in patients with r/r ALL.  

This study involved 34 patients with B-ALL who had received B (18 patietns) or IO (16 patients) treatment. In the B group, 13 patients had r/r disease and 5 were MRD-positive. MRD is when there is a small amount of cancer cells left after treatment. MRD negative means there are no cancer cells left. In the IO group, all patients were treated for r/r disease.

69% of patients who received B for r/r ALL achieved complete remission (CR). 78% of patients who achieved CR reached minimal residual disease (MRD) negativity. All patients who were MRD positive achieved MRD negativity after B treatment. The 1-year overall survival (OS) rate of patients receiving B for r/r B-ALL was 54%. The 1-year OS rate for patients receiving B for MRD positivity was 80%. 

The rate of CR for patients treated with IO was 94%. 67% of these patients reached MRD negativity. The 1-year OS rate after treatment of IO was 46%.  

79% of the patients treated with B proceeded to SCT. Of the patients using IO, 80% proceeded to SCT.   

The most frequent side effects for B treatment were cytokine release syndrome (CRS) and nerve damage. CRS is when there is a release of inflammatory cells called cytokins into the blood. CRS involves fever, nausea, headache, rapid hert rate, low blood pressure and trouble breathing. The most common side effect for IO treatment was a blockage in the blood vessels of the liver.

This study concluded that both blinatumomab and inotuzumab ozogamicin are effective salvage regimens in r/r B-ALL before SCT. 

This study included a very small number of participants. Also, the two drugs were not compared in terms of effectiveness. Therefore, which drug is more effective remains unclear.