Philadelphia chromosome negative B-cell acute lymphoblastic leukemia in older adults: Current treatment and novel therapies

Older adults with Philadelphia chromosome negative (Ph-),-B-cell acute lymphoblastic leukemia (ALL) have the highest rates of treatment failure and treatment complications with current therapy, and, thus, there is no standard treatment for these patients. Approximately 16 percent of patients with newly diagnosed Ph- B-cell ALL are aged 60 years or older [1]. The five-year overall survival for this older cohort of patients is approximately 20 percent, and there has been no improvement in their survival in decades [2]. The challenge in managing older patients with ALL is achieving balance between efficacy of treatment and the toxicity of multi-agent chemotherapy. The latter approach is highly effective in younger adults, but greatly limited by toxicity in older adults. New classes of agents, bi-specific T-cell engager (BiTE) monoclonal antibody and antibody drug conjugates (ADC) have been introduced into the treatment of ALL, and these agents have achieved therapeutic responses and manageable toxicity in patients of all ages with relapsed refractory ALL. These newer immunotherapy agents may improve the treatment of older adults. This review focuses on the new approaches to treatment of Ph- B-cell ALL in older patients. Other reviews in this special edition of ALL will focus on Philadelphia chromosome positive ALL, Philadelphia-like ALL, and allogeneic stem cell transplant as related to older adults.