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Introduction: Lymphodepleting chemotherapy (LDC) is critical to CAR T-cell expansion and efficacy. Despite this, there is not a consensus in the literature regarding the optimal LDC regimen, including dose and frequency. Methods: We retrospectively reviewed consecutive patients at a single institution that received LDC prior to treatment with the CD19 directed CAR T-cell products axicabtagene ciloleucel and tisagenlecleucel. Patients treated at our center received fludarabine 30 mg/m2 and cyclophosphamide 500 mg/m2 for 3 consecutive days prior to May 2019. After this timepoint patients routinely received fludarabine 40 mg/m² and cyclophosphamide 500 mg/m² for 2 consecutive days. Clinical data from each cohort were obtained from the electronic medical record and compared for differences in CAR T-cell efficacy and toxicity. Results: From June 2018 to August 2023, LDC was given to 92 patients prior to CD19 directed CAR T-cell therapy for relapsed non-Hodgkin's lymphoma. Twenty-eight patients received a 3-day regimen, and 64 patients received a 2-day regimen. In the total cohort, 75% of patients received axicabtagene ciloleucel and 25% received tisagenlecleucel. The overall response rates in both the 2-day regimen group and the 3-day regimen group were similar (69% vs 75%, p= 0.21) as were the complete response rates (50% vs 54%, p=0.82). There were no significant differences between the 2-day and 3-day regimens for grade 2-4 cytokine release syndrome (55% vs 50%, p=0.82), grade 2-4 immune effector cell associated-neurotoxicity syndrome (42% vs 29%, p=0.25), or time to resolution of neutropenia or thrombocytopenia. The rate of prolonged platelet recovery lasting greater than 60 days was higher with the 3-day regimen (9% vs 27%, p=0.026). Discussion: As the number of patients eligible for CAR T-cell therapy continues to increase, optimizing each component of therapy is necessary. We show that a 2-day regimen of LDC with fludarabine and cyclophosphamide is feasible without significant impact on CAR T-cell efficacy or toxicity. Prospective studies are necessary to further determine the most effective LDC regimen. [ABSTRACT FROM AUTHOR]

Background: Late complications of chemotherapy include treatment‐related secondary leukemias. We describe an unusual case of a new treatment‐related acute lymphoblastic leukemia (t‐ALL) that was unmasked and mobilized by G‐CSF during autologous hematopoietic progenitor cell collection (HPCC) in a young man with testicular cancer. Methods: Electronic chart review of the patient medical history and pertinent laboratory findings. Patient CD34 and blast results were compared to 4249 autologous and 437 allogeneic HPCC performed between 2004 and 2022. In autologous donors, the %blast and %CD34 were compared by linear regression and paired t‐test using commercial software. Results: The patient was a 21‐year‐old male with relapsed testicular cancer referred for G‐CSF cytokine‐only mobilization and autologous HPCC. His pre‐mobilization WBC count and differential were normal. On the day of HPCC, his WBC = 37.9 K/mcL with 12% blasts and 9.75% circulating CD34+ cells. The patient was admitted 9 days after HPCC with a normal WBC count and 15% blasts. He was diagnosed with a pro‐B t‐ALL bearing an t(4:11)(q21:q23) translocation and KMT2A‐AF4 rearrangement. Upon review, this patient had the highest %CD34 among 4686 HPCC and was the only donor with %CD34 > 1% after a cytokine‐only mobilization. Conclusion: We report a case of t‐ALL that mimicked CD34+ HPC and was mobilized by high‐dose G‐CSF. Up to 70% of secondary leukemias bear 11q23/KMT2A rearrangements, which occur at the multipotent stem cell stage and can result in myeloid and lymphoid leukemias. Donors who have received past chemotherapy, especially with topoisomerase II inhibitors, are at increased risk for 11q23/KMT2A leukemias. [ABSTRACT FROM AUTHOR]

Analysis of culled arthropod prey parts collected from beneath four feeding perches was used to assess prey taken by Nycteris grandis from November 1987 to May 1988. The perches were located along the Zambezi River in Mana Pools National Park in Zimbabwe. With the exception of an occasional solifugid, N. grandis ate mainly insects in addition to frogs and other small vertebrates. Three species of katydids and many species of moths were the most common prey. While hats using one feeding perch fed heavily on two species of cicadas at times, those at the other perches rarely did. There also were differences in the incidences of antlions, mantids and beetles in the diets of bats using different perches. Extensive samples from two feeding roosts about 2 km apart showed significant differences in prey composition. Smaller samples from two sites closer to one another showed similar patterns of the incidence of different prey. [ABSTRACT FROM AUTHOR]