Minimal residual disease (MRD) in chronic lymphocytic leukemia (CLL) is defined as <1 CLL cell per 10,000 leukocytes (0.01%; <10−4). Flow cytometry and next-generation sequencing have demonstrated high sensitivity in MRD detection. MRD assessment may help to determine prognosis after fixed-duration regimens; this has been established in the contexts of chemoimmunotherapy and venetoclax/antibody combinations. In the short term, MRD status does not seem to inform prognosis in patients treated with a BTK inhibitor plus venetoclax-based regimens; however, long-term data will be needed to determine whether it is beneficial in this population. Numerous trials have demonstrated that MRD may be used to guide therapy. It is unclear whether using an MRD-guided treatment strategy is better than using fixed-duration therapy; ongoing and future studies are warranted.
Presenter: Jennifer A. Woyach
Nisha Rao, Hans Iwenofu, Bingfeng Tang, Jennifer Woyach, and David A. Liebner
Inflammatory myofibroblastic tumors (IMTs) are soft tissue neoplasms with rare metastatic potential. Approximately half of IMTs are positive for an ALK rearrangement, and ALK inhibitors have been used successfully in the treatment of IMTs with a variety of ALK fusions. This report describes a 21-year-old woman with an aggressive, metastatic IMT with a novel NUMA1-ALK fusion that showed a dramatic response to the ALK inhibitors crizotinib and alectinib. To our knowledge, this report provides the first published description of an IMT with a NUMA1-ALK fusion. The patient's aggressive IMT responded favorably to crizotinib and alectinib, suggesting that ALK inhibitors may be effective in IMT with NUMA1-ALK fusions. We review published reports of ALK-driven IMTs that have received ALK inhibitor therapy and suggest characteristics that may be associated with favorable response to treatment. We also discuss the strengths and limitations of immunohistochemistry, fluorescence in situ hybridization, and next-generation sequencing in the diagnosis and management of IMTs.