Antibody-Drug Conjugate Clears Residual Cancer in 70% of Leukemia Patients

Researchers at The University of Texas MD Anderson Cancer Center were able to eradicate measurable residual disease (MRD) in B-cell acute lymphoblastic leukemia (ALL) patients, a critical step in improving long-term survival outcomes, by treating with the antibody-drug conjugate (ADC) inotuzumab ozogamicin. 

Results from the Phase 2 study were published in Blood Cancer Journal. Among 37 patients treated, 70% achieved MRD negativity, including strong responses in both Philadelphia chromosome-positive and -negative disease. Patients who were treated earlier had the most favorable outcomes. Relapse-free survival was 40 months, and median survival was 61 months.

“Our results show that inotuzumab is highly effective at clearing residual disease in patients already in remission, with durable responses and encouraging survival,” said principal investigator Elias Jabbour, M.D., professor of Leukemia. “This approach has the potential to deepen remissions and change how we manage patients at high risk of relapse.” 

What do the trial results mean for patients with B-cell ALL? 

These results suggest this ADC treatment may offer patients a strong chance of clearing remaining disease, even after they have been treated with other therapies. Clearing MRD is a strong predictor of whether a patient will relapse. When MRD is cleared and becomes undetectable, patients generally have an increased chance of staying in remission. In addition, this treatment can potentially help patients reach the point of becoming eligible for stem cell transplant or chimeric antigen receptor (CAR) T cell therapy in a safer, lower-disease state. 

The treatment was well tolerated, and side effects were manageable. 

These findings highlight inotuzumab as a promising strategy to deepen remissions and potentially improve long-term outcomes by eradicating residual leukemia.