Pre-exposure prophylaxis with tixagevimab/cilgavimab for coronavirus disease 2019 (COVID-19) during the Omicron BA.5 wave at a single institution in Japan.

Pre-exposure prophylaxis with tixagevimab/cilgavimab was considered a useful strategy to protect immunocompromised patients from COVID-19 based on the phase 3 PROVENT trial conducted between November 2020 and March 2021. However, after late 2021, the dominant substrains of COVID-19 changed to Omicron substrains, which showed resistance to tixagevimab/cilgavimab. Therefore, it is important to re-evaluate the real-world efficacy of tixagevimab/cilgavimab for the prevention of COVID-19 in the Omicron era. To this end, we retrospectively evaluated the efficacy and safety of tixagevimab/cilgavimab prophylaxis for COVID-19 during the Omicron BA.5 wave in Japan. A total of 240 consecutive patients with hematologic malignancies received tixagevimab/cilgavimab at our institution from October 18, 2022, to January 31, 2023. Among them, the cumulative incidence of COVID-19 at 90 days was 6.4%. A total of 10/14 (71.4%) had mild infection, and 4/14 (28.5%) had severe infection. No patient died due to COVID-19. Adverse events consisted of deep vein thrombosis in 2 patients. Our analysis indicated that pre-exposure prophylaxis with tixagevimab/cilgavimab might have clinical effectiveness in reducing the severity of COVID-19 in Japanese HM patients, even in the Omicron BA.5 surge. It also suggested that tixagevimab/cilgavimab may be associated with cardiovascular complications.

[Hypokalemia and potassium replacement therapy in allogeneic hematopoietic stem cell transplantation].

Hypokalemia is common in allogeneic hematopoietic stem cell transplantation (allo-HCT) patients and is associated with non-relapse mortality (NRM). Therefore, it is extremely important to replace potassium adequately. We evaluated the safety and efficacy of potassium replacement therapy by retrospectively analyzing the incidence and severity of hypokalemia in 75 patients who received allo-HCT at our institution. 75% of patients developed hypokalemia during the allo-HSCT, and 44% of patients had grade 3-4 levels of hypokalemia. NRM was significantly higher in patients with grade 3-4 hypokalemia than in patients without severe hypokalemia (one-year NRM: 30% vs 7%, p=0.008). Although 75% of the patients required potassium replacement that exceeded the range of potassium chloride solutions package inserts in Japan, we did not experience any adverse events associated with hyperkalemia. Our current observations suggested that the Japanese package insert for potassium solution injection should be revised for potassium needs.

Presence of bone marrow fibrosis in multiple myeloma may predict extramedullary disease.

We analyzed the incidence of bone marrow fibrosis in 91 newly diagnosed Japanese multiple myeloma (MM) patients and evaluated the impact of fibrosis on clinical characteristics and therapeutic outcomes. Thirty-four (37%) patients had greater than grade 1 bone marrow fibrosis. The presence of bone marrow fibrosis did not affect laboratory data, the percentage of plasma cells in bone marrow or cytogenetic findings. It also had no significant effect on response to initial treatment, engraftment after autologous hematopoietic stem cell transplantation or overall survival. Interestingly, the incidence of extramedullary disease at diagnosis was significantly higher in patients with bone marrow fibrosis (p = 0.006). Analysis of biological characteristics of MM cells revealed that expression of CD49e, an alpha5/beta1 integrin, was downregulated in MM cells derived from patients with bone marrow fibrosis (p = 0.026). When seven of the original 34 patients were re-evaluated for fibrosis grading after treatment, five (71%) showed a reduction in fibrosis. Our present findings suggest that the presence of bone marrow fibrosis may predict development of extramedullary disease in MM.

Real-world experience of treatment with thrombopoietin receptor agonists in anti-thymocyte globulin-naïve patients with aplastic anemia: an observational retrospective analysis in a single institution.

OBJECTIVE: To explore the efficacy and safety of thrombopoietin receptor agonists (TPO-RAs) without anti-thymocyte globulin (ATG) in ATG-naïve patients with aplastic anemia (AA) in a real-world setting. METHODS: We retrospectively evaluated treatment outcomes in 45 consecutive ATG-naïve patients with AA who received TPO-RAs between 2017 and 2021 at our hospital. RESULTS: ATG ineligibility was due to advanced age (≥ 70 years), n = 22; not recommended under Japanese guidelines due to mild symptoms, n = 13; patient preference, n = 6; uncontrolled heart failure, n = 2; uncontrolled diabetes mellitus, n = 2; chronic renal failure, n = 2; invasive aspergillosis, n = 1. Twenty-eight patients (62%) achieved hematologic response in at least unilineage after 6 months' treatment, while 38 (84% in unilineage response-eligible patients) and four (25% in trilineage response-eligible patients) patients achieved at least unilineage and trilineage responses, respectively, at any point during the follow-up period. Five patients switched from eltrombopag to romiplostim because of adverse events or lack of efficacy, and two developed hematologic malignancies. Eltrombopag was effective even in elderly ATG-ineligible patients with severe AA. The 2-year overall survival rate was 84.3%, with a median 26.3-month follow-up. Time from diagnosis to eltrombopag treatment initiation tended to affect the response (p = 0.0727), but no factors that significantly predicted hematologic response were identified. CONCLUSIONS: We found eltrombopag to be effective even in elderly ATG-naïve patients with severe AA, indicating that TPO-RA treatment should be considered in patients ineligible for ATG treatment because of age, complications, or severe AA.

Transdifferentiation of mantle cell lymphoma into sarcoma with limited neuromuscular differentiation after conventional chemotherapy.

We report an exceptionally rare case of mantle cell lymphoma (MCL) that transdifferentiated into sarcoma with limited neuromuscular differentiation. An 81-year-old man with t(11;14)-positive MCL was treated with rituximab and bendamustine and achieved complete remission; however, just 2 months later, the patient developed multiple systemic tumors. Pathologic studies revealed round cell sarcoma expressing synaptophysin, CD56, and myogenin without any B-cell markers. The CCND1 translocation and an identical IGL gene rearrangement were shared by both the MCL and sarcoma. Whole-exome sequencing detected 189 single nucleotide variants (SNVs) in the MCL and 205 SNVs in the sarcoma; 160 SNVs including NSD2, ATM, RB1, and TP53 mutations were shared between MCL and sarcoma cells. An additional PTPN11 mutation was specifically found in the sarcoma. These findings confirmed the shared clonal origin of MCL and sarcoma in this patient and indicated that MCL can transdifferentiate into sarcoma in rare cases.