ALL-318: Real-World Outcomes of Adults with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia Who Did Not Receive Allogeneic Stem Cell Transplant at the University of Michigan

Context: The current standard of care for Ph+ ALL is concurrent chemotherapy or corticosteroids with a TKI, followed by an allogeneic transplant for those who are eligible and have attained complete morphologic remission. However, recent studies have suggested that transplant may not be necessary for all patients with Ph+ ALL, especially those who achieve CMR after induction. Objective: Our objective is to analyze the outcomes and characteristics of patients with Ph+ ALL treated within our institution who did not undergo allogeneic stem cell transplant. Design: We conducted a retrospective cohort study of patients with Ph+ ALL who did not undergo allogeneic stem cell transplant treated at the University of Michigan between 2007 and 2019. Main Outcome Measures: The primary outcome measurements of our study were overall survival (OS) and event-free survival (EFS). Results: 31 patients were identified in our database and met eligibility criteria. 30/31 patients received an upfront TKI (20 received dasatinib, 9 received imatinib, and 1 received ponatinib). 11 patients had molecular testing, and 4 had an IKZF1 mutation. The median OS was 388 days, with a median EFS of 247 days. 7 patients were deemed medically eligible for transplant but did not undergo transplant for reasons including patient preference and lack of an adequately matched donor. The median OS was 372 days for these 7 patients. 10/31 patients achieved CMR, with a median time to CMR of 148.5 days. The median OS in patients who achieved CMR was 551 days. The median OS for those who survived at least 50 days after diagnosis was 494 days. Cox regression analysis found an HR of.129 [0.020–0.841] for initial induction with hyperCVAD + TKI and an HR of 10.177 [1.209–85.677] with dexamethasone, vincristine, and TKI. No significant difference in OS was observed based on the choice of TKI. All patients who achieved CR experienced relapse or death during follow-up. Conclusions: Our results reveal poor outcomes in non-transplanted patients with Ph+ ALL and support the current standard of care utilizing concomitant chemotherapy and TKI with allogeneic transplant in those who are medically eligible.