Hiroyuki Takamori

NUP98 rearrangements represent a distinct, high-risk subtype of acute myeloid leukemia (AML), particularly in pediatric patients. However, their prevalence, genetic features, and clinical implications in adult AML remain poorly characterized. Using targeted-capture sequencing, we identified 41 cases with NUP98 rearrangements among 1569 AML cases, representing the majority of 44 NUP98-rearranged cases detected across 4753 myeloid neoplasms. Fifteen distinct fusion partners were detected, with NUP98::NSD1 and NUP98::HOXA9 being the most frequent. Notably, two novel fusions—NUP98::MEOX2 and NUP98::HOXA6—were identified. Co-mutations were relatively infrequent; FLT3-ITD and WT1 mutations were the most common, while NPM1 mutations were exclusive. FLT3-ITD was significantly enriched in NUP98::NSD1 cases, whereas TET2 mutations were more frequent in NUP98::HOXA9 cases. Clonal hierarchy analysis suggested that NUP98 rearrangements occur early in leukemogenesis. NUP98-rearranged AML exhibited higher relapse rates and shorter event-free survival. Specifically, NUP98::NSD1 was associated with a poor induction response, whereas NUP98::HOXA9 and NUP98 fusions with other partners showed higher remission rates but frequent relapse. Allogeneic hematopoietic stem cell transplantation was associated with better survival, underscoring its significance. These findings reveal the genetic and clinical heterogeneity of NUP98-rearranged AML in adults and support its classification as a distinct entity, highlighting the need for fusion partner-specific therapeutic strategies.

NUP98 rearrangements represent a distinct, high-risk subtype of acute myeloid leukemia (AML), particularly in pediatric patients. However, their prevalence, genetic features, and clinical implications in adult AML remain poorly characterized. Using targeted-capture sequencing, we identified 41 cases with NUP98 rearrangements among 1569 AML cases, representing the majority of 44 NUP98 -rearranged cases detected across 4,753 myeloid neoplasms. Fifteen distinct fusion partners were detected, with NUP98::NSD1 and NUP98::HOXA9 being the most frequent. Notably, two novel fusions— NUP98::MEOX2 and NUP98::HOXA6 —were identified. Co-mutations were relatively infrequent; FLT3 -ITD and WT1 mutations were the most common, while NPM1 mutations were exclusive. FLT3 -ITD was significantly enriched in NUP98::NSD1 cases, whereas TET2 mutations were more frequent in NUP98::HOXA9 cases. Clonal hierarchy analysis suggested that NUP98 rearrangements occur early in leukemogenesis. NUP98 -rearranged AML exhibited higher relapse rates and shorter event-free survival. Specifically, NUP98::NSD1 was associated with a poor induction response, whereas NUP98::HOXA9 and NUP98 fusions with other partners showed higher remission rates but frequent relapse. Allogeneic hematopoietic stem cell transplantation was associated with better survival, underscoring its significance. These findings reveal the genetic and clinical heterogeneity of NUP98 -rearranged AML in adults and support its classification as a distinct entity, highlighting the need for fusion partner-specific therapeutic strategies.

Venetoclax plus azacitidine (VEN + AZA) is widely used in acute myeloid leukemia (AML). This study explored the role of static and dynamic profiles of mutational clonal burden to predict outcomes by analyzing marrow samples from 228 VEN + AZA treated AML cases at “Pre-treatment” (n = 228), “Best-response” (n = 105), and “Relapse” (n = 27) phases using targeted-capture sequencing. In a multivariate model, older age, prior AZA, TP53 mutation with variant allele frequency ≥0.10, and RAS-pathway mutations predicted shorter overall survival (OS), while BCORL1 mutation predicted longer OS. Notably, myelodysplasia-related gene mutations, which constitute adverse factors in ELN 2022, predicted favorable survival. Achieving composite complete remission (CRc) significantly predicted longer OS (P < 0.001) but showed residual mutations in 76.2% of the cases. Among CRc cases, relapse-free survival was stratified by molecular clearance of mutations other than DNMT3A, ASXL1, and TET2 (P = 0.04). In addition, 37% of relapsed cases showed a change of major clones, with 40% having potential targets of molecular-targeting treatment. This study revealed the novel prognostic role of myelodysplasia-related gene mutations and established the importance of molecular response assessment in CRc phase.

Myeloproliferative neoplasms (MPNs) are characterized by clonal proliferation of hematopoietic stem cells, which can lead to secondary myelofibrosis or acute myeloid leukemia. We explored the changes in genomic alterations during MPN transformation using whole-genome sequencing of samples from both the chronic and fibrotic or leukemic phases of 20 patients. We identified FOXP1 mutations in 3 of 14 (21.4%) patients with secondary myelofibrosis. This novel mutation was identified in another 5 of the 35 patients (14.3%) in an independent cohort. All these 8 patients with FOXP1 mutations did not experience leukemic transformation after a median follow-up of 5.1 years. The acquisition of non-canonical MPL^Y591 mutations was detected in the fibrotic or leukemic phase. Clonal expansion, involving both known and unknown driver genes (in 18 and 2 patients, respectively), was observed in all patients. We determined the patterns of clonal evolution based on myeloid driver mutations in 18 patients: linear clonal evolution in 11 patients and branched clonal evolution in 7 patients. Our results suggested that MPN patients carrying FOXP1 mutations are unlikely to have leukemia transformation and emphasized that the acquisition of specific genetic mutations and dynamic changes in clonal architecture underlie the pathogenesis in patients undergoing MPN transformation.

Histiocytic neoplasms (HNs) in adults have been reported to be associated with a high prevalence of coexisting haematological and solid malignancies. While a proportion of coexisting HNs and haematological malignancies share identical genetic alterations, the genetic association between HNs and solid malignancies has scarcely been reported. We report a case of Rosai–Dorfman disease (RDD) complicated by coexisting clear cell sarcoma (CCS). RDD is a rare HN. CCS is an ultrarare soft tissue sarcoma with a poor prognosis. Mutation analysis with whole‐exome sequencing revealed six shared somatic alterations including NRAS p.G12S and TP53 c.559+1G>A in both the RDD and CCS tissue. This is the first evidence of a clonal relationship between RDD and solid malignancies using mutational analysis. We hypothesise that neural crest cells, which originate in CCS, are likely the common cells of origin for RDD and CCS. This case helps to unravel the underlying clinicopathological mechanisms of increased association of solid malignancies in HNs. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Introduction Crovalimab is a novel anti-complement component 5 (C5) monoclonal antibody engineered with the Sequential Monoclonal Antibody Recycling Technology (SMART-Ig; Fukuzawa et al, Sci Rep. 2017) to extend half-life and enable infrequent, subcutaneous (SC) self-administration in C5-mediated diseases. Crovalimab is being investigated as a therapy for paroxysmal nocturnal hemoglobinuria (PNH), a disease for which C5 inhibition is the standard of care. The Phase I/II COMPOSER trial (NCT03157635; Röth, et al. Blood. 2020) is a global, open-label, multicenter study of crovalimab consisting of 4 sequential parts. Parts 1, 2, and 3 assessed the pharmacokinetics (PK) and safety of crovalimab in healthy volunteers, C5 inhibitor-naive patients, and patients switched from eculizumab, respectively. Part 4 assessed an optimized crovalimab dose and regimen in naive and switched patients with PNH. Because eculizumab and crovalimab bind to different C5 epitopes, drug-target-drug complexes (DTDCs) consisting of eculizumab, C5, and crovalimab motifs can temporarily form in the circulation of patients who switch treatments. DTDCs can form in a range of sizes, from single crovalimab-C5-eculizumab motif to larger complexes with multiple motifs. Larger DTDCs are a concern because they take longer to clear and may be more likely to induce type III hypersensitivity reactions. Objectives Describe the impact of DTDC formation on the safety, PK, and pharmacodynamics of crovalimab in patients with PNH who switched from eculizumab to crovalimab and to describe the effect of crovalimab dose on DTDC size distribution and kinetics. Study Design and Methods Using data from COMPOSER Parts 1-3, a biochemical mathematical model was developed to investigate the kinetics of the formation and dissociation of DTDCs under the assumption that larger complexes are formed by the reversible binding of smaller complexes. The model was calibrated using concentration-time profiles of total C5, total crovalimab, and the concentration of eculizumab at the time of crovalimab initiation. DTDC size distributions were measured using size-exclusion chromatography coupled to enzyme-linked immunosorbent assay. Using model-based simulations, an optimized crovalimab dosing strategy was identified to reduce the formation of large DTDCs while maintaining serum concentration of crovalimab above the target level of ≈ 100 μg/mL. The optimized dose and regimen were a loading series of 1000 mg intravenously on day 1 and 340 mg SC on days 2, 8, 15, and 22, followed by maintenance dosing of 680 mg SC every 4 weeks starting on day 29. The loading dose series increased the total crovalimab dose received during the first month of treatment to reduce the formation of larger DTDCs, in line with the lattice theory of complex formation. This optimized dosing strategy was investigated in Part 4 patients who switched from eculizumab. Results In COMPOSER, 19 patients with PNH were enrolled in Part 3 and switched from eculizumab to crovalimab. DTDCs were observed in all patients from Part 3 (Figure; larger DTDCs are found in fractions 1-4 and smaller crovalimab-containing complexes, such as single motifs and single crovalimab molecules, are found in fractions 5 and 6). Two Part 3 patients experienced clinical manifestations compatible with type III hypersensitivity reactions that were ascribed to DTDCs. The DTDC size distribution in Part 4 patients, who received the optimized dosing strategy, evolved differently than in Part 3 patients, consistent with model predictions. In the switched patients from Part 4, large DTDC levels started to decrease on day 8 and continued to decrease, in contrast to Part 3, in which they started to decrease on day 15. On day 22, the mean percentage of the largest DTDCs was reduced by 56% in patients in Part 4 relative to patients in Part 3. Part 4 patients achieved and maintained serum crovalimab concentrations above ≈ 100 µg/mL throughout follow-up. Despite DTDCs being observed in all Part 4 patients who switched from eculizumab, no adverse events suggestive of a type III hypersensitivity reaction occurred. Conclusions The optimized crovalimab regimen resulted in lower concentrations of large DTDCs than in patients who received the Part 3 regimen and reduced the persistence of DTDCs in patients who switched treatment. This regimen is now being evaluated in the Phase III COMMODORE 1 (NCT04432584) and COMMODORE 2 (NCT04434092) studies.

The majority of lung cancer patients are discovered at advanced stages and some of them may often have complex medical problems in addition to the diagnosis of cancer, such as oncologic emergency requiring assistance in an intensive care unit (ICU). In the last decade, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have been recognized as key drugs for non-small cell lung cancer (NSCLC) harboring sensitive EGFR mutation. We report a case of stage IV NSCLC with EGFR mutation (exon 19 deletion). He was in a life-threatening stage due to a massive intrathoracic hemorrhage. After chest tube drainage and mechanical ventilation, afatinib was administered through nasogastric tube. Consequently, a dramatic response was obtained and he was able to be discharged from our hospital 11 weeks after the initiation of afatinib. This approach may be of benefit to rescue from life-threatening condition for selected patients.