Outcomes of stem cell transplant for patients with acute lymphoblastic leukemia after inotuzumab ozogamicin treatment

This study aimed to investigate the outcomes of allogeneic stem cell transplant (allo-SCT) after treatment with inotuzumab ozogamicin (Besponsa) for patients with relapsed/unresponsive acute lymphoblastic leukemia (ALL). This study concluded that allo-SCT provided optimal long-term survival benefit for these patients.

Relapsed or unresponsive ALL is challenging to treat. Inotuzumab ozogamicin (InO) is a targeted therapy used for the treatment of these patients.  

Allo-SCT is a procedure in which a person receives blood-forming stem cells from a genetically similar, but not identical, donor. This is often a sister or brother but could also be an unrelated donor. Allo-SCT is often offered to patients with relapsed or unresponsive ALL. However, the outcomes of allo-SCT after treatment with InO in these patients are still under investigation. 

This study involved 236 InO treated patients with relapsed or unresponsive ALL. 43% (101) proceeded to allo-SCT and were included in this analysis. 

The average post-transplant overall survival (OS; time from transplant to death from any cause) was 9.2 months. The 2-year survival probability was 41%. Compared to standard treatment, patients who received InO had a lower 2-year risk of relapse (45.7% with standard treatment vs 28.6% with InO).

In first-time allo-SCT patients, the average OS was 11.8 months. The 2-year survival probability was 46%. Some patients relapsed and needed more treatment before SCT. Patients that went directly to first-time HSCT upon remission had a  2-year survival probability of 51%.  

This study concluded that in patients with relapsed or unresponsive ALL, InO followed by allo-HSCT provided optimal long-term survival benefit for those with no previous allo-HSCT who went directly to transplant after remission. 

This study included a small number of participants. Further studies are needed.