Clinical outcomes and frequency of persistent infection among immunosuppressed patients treated with bebtelovimab for COVID-19 infection at an ambulatory cancer center.

BACKGROUND: There are limited data on clinical outcomes associated with the use of bebtelovimab for the treatment of coronavirus disease 2019 (COVID-19) among cancer patients. We aimed to define the clinical characteristics and outcomes among patients receiving bebtelovimab as part of the COVID-19 therapeutics program at our cancer center. METHODS: This is a retrospective cohort study of immunosuppressed adult patients who received bebtelovimab at Fred Hutchinson Cancer Center between March 2022, and November 2022. We reviewed medical records to capture the date of the first positive COVID-19 test, clinical characteristics, outcomes, and follow-up COVID-19 testing for 60 days after the first positive. Persistent infection was defined as a positive test beyond day 30; these patients were reviewed beyond day 60. RESULTS: Among 93 patients who received bebtelovimab, 64 (69%) had hematologic malignancy. Sixty-nine (74%) patients received bebtelovimab within 2 days after diagnosis. Two (2%) patients were hospitalized, none required ICU care, and one patient died on day 52; although it is unknown if death was directly related to COVID-19. Ten (11%) patients had persistent COVID-19 infection; of these, four received additional COVID-19 therapy with either nirmatrelvir/ritonavir or remdesivir, and five out of six patients with sequencing data available had spike protein mutations associated with bebtelovimab resistance. CONCLUSION: A coordinated systems-based approach led to prompt initiation of bebtelovimab within two days of testing positive in most patients. We observed few hospitalizations or deaths. Persistent infection was noted in 11% of patients with four requiring additional therapies, highlighting a need for novel strategies to manage immunosuppressed patients.

Distinct effects of concomitant Jak2V617F expression and Tet2 loss in mice promote disease progression in myeloproliferative neoplasms.

Signaling mutations (eg, JAK2V617F) and mutations in genes involved in epigenetic regulation (eg, TET2) are the most common cooccurring classes of mutations in myeloproliferative neoplasms (MPNs). Clinical correlative studies have demonstrated that TET2 mutations are enriched in more advanced phases of MPNs such as myelofibrosis and leukemic transformation, suggesting that they may cooperate with JAK2V617F to promote disease progression. To dissect the effects of concomitant Jak2V617F expression and Tet2 loss within distinct hematopoietic compartments in vivo, we generated Jak2V617F/Tet2 compound mutant genetic mice. We found that the combination of Jak2V617F expression and Tet2 loss resulted in a more florid MPN phenotype than that seen with either allele alone. Concordant with this, we found that Tet2 deletion conferred a strong functional competitive advantage to Jak2V617F-mutant hematopoietic stem cells (HSCs). Transcriptional profiling revealed that both Jak2V617F expression and Tet2 loss were associated with distinct and nonoverlapping gene expression signatures within the HSC compartment. In aggregate, our findings indicate that Tet2 loss drives clonal dominance in HSCs, and Jak2V617F expression causes expansion of downstream precursor cell populations, resulting in disease progression through combinatorial effects. This work provides insight into the functional consequences of JAK2V617F-TET2 comutation in MPNs, particularly as it pertains to HSCs.

Epidemiology and Outcomes of Recurrent C Difficile Infection Among Hematopoietic Cell Transplant Recipients: A Single-center, Retrospective 10-year Study.

Background: There are limited data on the contemporary epidemiology of recurrent Clostridioides difficile infection (CDI) among hematopoietic cell transplant (HCT) recipients. We aimed to determine the incidence, risk factors, and outcomes for recurrent CDI among HCT recipients. Methods: We conducted a retrospective study of adult HCT recipients between 2012 and 2021 diagnosed with index CDI between HCT day -7 and +100. Recurrent CDI was defined as new symptoms and a positive test within 12 weeks after treatment for index CDI. Cox proportional hazards models were used to investigate associations between prespecified variables (age, neutropenia, exposure to antibiotics with antianaerobic coverage, cytomegalovirus viremia/disease, and metronidazole monotherapy) and recurrent infection, presented as hazard ratios with 95% confidence intervals (CI). Results: Of 3479 HCT recipients, 416 (12%) had index CDI and were treated with oral vancomycin (31%), metronidazole (41%), oral vancomycin and metronidazole (29%). Of 381 patients eligible for recurrent CDI analysis, 35 had recurrent infection; cumulative incidence was 10% (95% CI, 7-13) at 12 weeks. In the 14 days after recurrence, 2/25 (8%) patients required hospital admission; none died within 30 days. Metronidazole monotherapy for treatment of index CDI was associated with an increased rate of recurrence (adjusted hazard ratio, 2.0; 95% CI, 1.0-4.0; P = .048). Conclusions: Recurrent CDI occurred in 10% of HCT recipients in the early posttransplant period and was associated with use of metronidazole. Further study is needed to characterize risk factors for recurrent CDI among HCT recipients to guide use of agents aimed at preventing recurrence.

COVID-19 Outcomes Among Hematopoietic Cell Transplant and Chimeric Antigen Receptor T-Cell Recipients in the Era of SARS-CoV-2 Omicron Variants and COVID-19 Therapeutics.

Recipients of cellular therapies, including hematopoietic cell transplant (HCT) and chimeric antigen receptor T-cell (CART) therapy, are at risk for poor outcomes from coronavirus disease 2019 (COVID-19). There are limited data describing outcomes among patients in the pre- and early post-cellular therapy period during the Omicron era when multiple antiviral therapeutics were widely available. The objective of this study is to describe COVID-19 treatment and outcomes in patients diagnosed with COVID-19 during the pre- or early post-cellular therapy period. This is a single-center retrospective cohort study of adult HCT and CART recipients diagnosed with COVID-19 in the pre- and early post-cellular therapy period who tested positive for COVID-19 at our cancer center between January 1, 2022 and March 1, 2023. Primary outcomes were 30-day COVID-19-related hospitalization and death. A secondary outcome was development of persistent COVID-19, defined by a positive SARS-CoV-2 polymerase chain reaction (PCR) 31 to 90 days after COVID-19 diagnosis. Among 65 patients included, 52 (80%) received at least one COVID-19 therapeutic. The most common treatment after initial COVID-19 diagnosis was nirmatrelvir/ritonavir (29%), followed by monoclonal antibody therapy (26%) and remdesivir (11%). Of the 64 patients with at least 30 days of follow-up, 8 (12%) had at least one COVID-19-related hospitalization and one patient died, though cause of death was not due to COVID-19. Of the 8 patients hospitalized for COVID-19, one had severe disease and 7 had mild or moderate infection. Persistent COVID-19 was observed in 13/65 (20%) patients, with 4 patients requiring additional antiviral therapy. Three pre-cellular therapy patients had delays in receiving cellular therapy due to persistent COVID-19. During the Omicron era, rates of 30-day COVID-19-related hospitalization and death were relatively low in this cohort of pre- and early post-HCT and CART recipients, the majority of whom received treatment with at least one antiviral agent. Persistent COVID-19 occurred in 1 in 5 patients in the peri-cellular therapy period and led to cellular therapy treatment delays in several patients, highlighting the need for new COVID-19 treatment strategies.

Management of disseminated intravascular coagulation in a patient with hepatic angiosarcoma: A case report.

RATIONALE: Hepatic angiosarcoma is a rare endothelial cell tumor that may lead to concurrent consumptive coagulopathies including disseminated intravascular coagulation (DIC). This report details a multifaceted approach to managing DIC in a patient with advanced-stage hepatic angiosarcoma, which continued to progress after a brief response to taxane-based chemotherapy. PATIENT CONCERNS: A 55-year-old man with a recent history of hemorrhoids and hemarthroses presented with acute rectal bleeding. He was found to have concurrent hepatomegaly, abnormal liver function tests, anemia, thrombocytopenia, and coagulopathy. DIAGNOSES: DIC in the setting of hepatic angiosarcoma. INTERVENTIONS: The patient's acute bleeding in the setting of DIC was controlled with a combination of antifibrinolytic agents to prevent clot breakdown, heparin products to prevent deposition of new clot, and romiplostim to increase platelet production. His angiosarcoma was treated with various combinations of chemotherapy, including taxane-based chemotherapy, doxorubicin, and pazopanib. OUTCOMES: The patient's DIC and acute bleeding on initial presentation improved following treatment with unfractionated heparin and low-molecular weight heparin maintenance therapy. It is unclear if the chemotherapy to treat the hepatic angiosarcoma played a significant role in the improvement of DIC. LESSONS: Laboratory measurement of prothrombin fragment 1.2, a byproduct of prothrombin conversion to thrombin, proved to be a useful way to monitor this patient's DIC over time.

Mutant Calreticulin Requires Both Its Mutant C-terminus and the Thrombopoietin Receptor for Oncogenic Transformation.

UNLABELLED: Somatic mutations in calreticulin (CALR) are present in approximately 40% of patients with myeloproliferative neoplasms (MPN), but the mechanism by which mutant CALR is oncogenic remains unclear. Here, we demonstrate that expression of mutant CALR alone is sufficient to engender MPN in mice and recapitulates the disease phenotype of patients with CALR-mutant MPN. We further show that the thrombopoietin receptor MPL is required for mutant CALR-driven transformation through JAK-STAT pathway activation, thus rendering mutant CALR-transformed hematopoietic cells sensitive to JAK2 inhibition. Finally, we demonstrate that the oncogenicity of mutant CALR is dependent on the positive electrostatic charge of the C-terminus of the mutant protein, which is necessary for physical interaction between mutant CALR and MPL. Together, our findings elucidate a novel paradigm of cancer pathogenesis and reveal how CALR mutations induce MPN. SIGNIFICANCE: The mechanism by which CALR mutations induce MPN remains unknown. In this report, we show that the positive charge of the CALR mutant C-terminus is necessary to transform hematopoietic cells by enabling binding between mutant CALR and the thrombopoietin receptor MPL.