Lineage switch (LS), defined as the immunophenotypic transformation of acute leukemia, has emerged as a mechanism of relapse after antigen-targeted immunotherapy, which is associated with dismal outcomes. Through an international collaborative effort, we identified cases of LS after a host of antigen-targeted therapies (eg, CD19, CD22, CD38, and CD7), described how LS was diagnosed, reviewed treatment approaches, and analyzed overall outcomes for this form of postimmunotherapy relapse. Collectively, 75 cases of LS were evaluated, including 53 (70.7%) cases of B-cell acute lymphoblastic leukemia (B-ALL) transforming to acute myeloid leukemia (AML), 17 (22.7%) cases of B-ALL transforming to mixed phenotypic acute leukemia (MPAL)/acute leukemias of ambiguous lineage (ALAL), and 5 (6.7%) cases of rare LS presentation (ie, T-cell ALL to AML). An additional 10 cases with incomplete changes in immunophenotype, referred to as “lineage drift” were also described. With a primary focus on the 70 cases of LS from B-ALL to AML or MPAL/ALAL, LS emerged at a median of 1.5 months (range, 0-36.5) after immunotherapy, with 81.4% presenting with LS within the first 6 months from the most proximal immunotherapy. Although most involved KMT2A rearrangements (n = 45, 64.3%), other rare cytogenetic and/or molecular alterations were uniquely observed. Treatment outcomes were generally poor, with remission rates of <40%. The median overall survival after LS diagnosis was 4.8 months. Outcomes were similarly poor for those with rare immunophenotypes of LS or lineage drift. This global initiative robustly categorizes lineage changes after immunotherapy and, through enhanced understanding, establishes a foundation for improving outcomes of LS.

Background: Oral therapeutic options for plexiform neurofibromas (PNs) in individuals with neurofibromatosis type 1 (NF1) are receiving attention in clinical research. The MEK inhibitor (MEKi) Selumetinib is FDA-approved in children ages 2+ years with inoperable PNs, and shows activity in adults. Prolonged therapy with selumetinib is necessary to maintain tumor reduction. Therefore, investigating long-term adherence is vital to understand patterns of adherence over time and its impact on clinical outcomes. Mixed methods research offers rich information about adherence that can inform future intervention trials, and can assist practitioners in addressing medication adherence concerns. Methods: This mixed-method pilot study is the first examination of the feasibility of a technology-based adherence assessment method, the medication events monitoring system (MEMS^TM), among individuals with NF1-PN. Adherence was monitored in a small sample of patients (N = 12; mean age = 34.36 years; 58% male) with NF1 and PN across eighteen 28-day treatment cycles. Qualitative data were obtained from individual interviews using inductive and deductive techniques for thematic analysis. Results: The predetermined criterion was met, suggesting that using MEMS^TM is feasible despite some challenges with the caps. Depression and overall stress were significantly related to reduced adherence, although these results should be considered hypothesis-generating. Barriers to medication adherence included forgetting and the timing of doses related to eating. Facilitators included consistency, reminders, and social support. Conclusions: This study highlights patient characteristics that may be related to increased risk for nonadherence, as well as challenges with electronic pill caps that should be considered in future clinical trials for NF1-related PN. Results can inform future adherence interventions for adults with NF1 and PNs. Future research with larger samples is needed to fully explore factors related to long-term medication adherence among individuals with NF1.