Lamb, Peter

Abstract Background: With over 1 billion individuals affected globally, obesity and obesity related diseases is now a leading cause of death. Metabolic and bariatric surgery (MBS) has emerged as a cornerstone intervention for severe obesity and its associated comorbidities. Despite its efficacy, postoperative care and follow-up after MBS remains highly variable worldwide. Objective: The PARTNER study aimed to evaluate global clinical practices in the postoperative management following MBS by surveying multidisciplinary healthcare professionals . Methods: This study was an international online survey conducted between October 2024 and January 2025. A multidisciplinary team developed the questionnaire based on existing literature and international guidelines. The survey assessed five domains: follow-up care, postoperative treatment, dietary management, patient support, and measurement of surgical outcomes. Responses were analysed descriptively. Results: A total of 262 responses were received from 62 countries. Most respondents were bariatric surgeons (72.1%) working in public healthcare systems (73.3%). While 78.7% reported conducting three-month postoperative reviews, only 23.7% offered indefinite follow-up. Hybrid models of care (virtual and in-person) were common (56.9%). VTE prophylaxis and postoperative PPI use were recommended by 64.1% and 84.3% respectively. Nearly all respondents (98.1%) provided dietary advice, with protein and micronutrient supplementation widely endorsed. Only 56.1% routinely referred patients for psychological follow-up. Definitions of surgical success and failure varied widely, with inconsistent objective outcome measures. Conclusion: The PARTNER study reveals significant international variation in postoperative management practices following MBS. These findings underscore the need for more standardized, evidence-based guidelines to improve long-term outcomes and equity of care worldwide.

SummaryGlobal obesity rates have risen dramatically, now exceeding deaths from starvation. Metabolic and bariatric surgery (MBS), initially for severe obesity (BMI ≥35 kg/m2), is performed globally over 500 000 times annually, offering significant metabolic benefits beyond weight loss. However, varying eligibility criteria globally impact patient care and healthcare resources. Updated in 2022, ASMBS and IFSO guidelines aim to standardise MBS indications, reflecting current understanding and emphasising comprehensive preoperative assessments. Yet, clinical variability persists, necessitating consensus‐based recommendations. This modified Delphi study engaged 45 global experts to establish consensus on perioperative management in MBS. Experts selected from bariatric societies possessed expertise in MBS and participated in a two‐round Delphi protocol. Consensus was achieved on 90 of 169 statements (53.3%), encompassing multidisciplinary team composition, patient selection criteria, preoperative testing, and referral pathways. The agreement highlighted the critical role of comprehensive preoperative assessments and the integration of healthcare professionals in MBS. These findings offer essential insights to standardise perioperative practices and advocate for evidence‐based guidelines in MBS globally. The study underscores the need for unified protocols to optimise outcomes and guide future research in MBS.

Abstract The FIP1L1-PDGFR-α fusion kinase induces hypereosinophilic syndrome (HES) in a subset of patients (pts). Imatinib is a potent inhibitor of PDGFR-α and has been associated with durable hematologic responses in pts with HES. However, development of kinase domain mutations may hamper TKI activity, underscoring the need for novel agents to prevent or overcome resistance. We evaluated the efficacy of the novel TKI EXEL-0862 in FIP1L1-PDGFR-α-expressing cells. In 72-hour MTS assay, EXEL-0862 inhibited EOL-1 cell proliferation with an IC50 of 1.0 nM and markedly decreased phosphorylation of STAT3 and Erk1/2, suggesting inhibition of downstream targets of PDGFR-α. More important, EXEL-0862 induced dose-dependent inhibition of PDGFR-α phosphorylation in peripheral blood mononuclear cells from a pt with HES. Exposure of EOL-1 cells to EXEL-0862 10 nM for 24 hours caused apoptosis as evidenced by flow cytometry (annexin-V/PI staining) and transmission electron microscopy. This was coupled with time-dependent cleavage of caspases-3, caspase-9, and PARP and with mitochondrial damage as reflected by cytochrome c translocation into the cytosol, and a diminished mitochondrial transmembrane potential. Of note, apoptotic features were not evident after 16 hours of EXEL-0862 exposure. Immunoblots showed marked downregulation of Mcl-1, but not of Bcl-2, Bcl-XL, or Bax. To elucidate the mechanism of Mcl-1 cleavage, EOL-1 cells were exposed to 10 nM EXEL-0862 for 6 hours followed by cycloheximide (5 μg/ml), a potent translation inhibitor, which resulted in marked Mcl-1 turnover. Treatment with the proteasome inhibitor MG-132 failed to abrogate EXEL-0862-induced Mcl-1 cleavage, suggesting proteasome-independent degradation. Rather, a decrease of pro-form Mcl-1 (p42) and increase of the cleaved Mcl-1 peptide form of Mcl-1 (p28) coincided with caspase-3 activation. Pretreatment with 20 μM pan-caspase inhibitor Z-VAD abolished EXEL-0862-induced Mcl-1 cleavage, pointing to a caspase--dependent mechanism. Collectively, our results establish EXEL-0862 as a solid candidate for the targeted treatment of pts with FIP1L1-PDGFR-α-positive HES.

Abstract Gain-of-function mutations of the receptor tyrosine kinase KIT play a key role in the pathogenesis of systemic mastocytosis (SM), gastrointestinal stromal tumors (GISTs), and some cases of acute myeloid leukemia (AML). Whereas KIT juxtamembrane domain mutations seen in most patients with GIST are highly sensitive to imatinib, the kinase activation loop mutant D816V, frequently encountered in SM, hampers the binding ability of imatinib. We investigated the inhibitory activity of the novel tyrosine kinase inhibitor EXEL-0862 against 2 subclones of human mast cell line-1 (HMC-1)—HMC-1.1, harboring the juxtamembrane domain mutation V560G, and HMC-1.2, carrying V560G and the activation loop mutation D816V, found in more than 80% of patients with SM. EXEL-0862 inhibited the phosphorylation of KIT in a dose-dependent manner and decreased cell proliferation in both mast cell lines with higher activity against HMC-1.2 cells. The phosphorylation of KIT-dependent signal transducer and activator of transcription-3 (STAT3) and STAT5 was abrogated upon exposure to nanomolar concentrations of EXEL-0862. In addition, EXEL-0862 induced a time- and dose-dependent proapoptotic effect in both mast cell lines and caused a significant reduction in mast-cell content in bone marrow samples from patients with SM harboring D816V and from those without the D816V mutation. We conclude that EXEL-0862 is active against KIT activation loop mutants and is a promising candidate for the treatment of patients with SM and other KIT-driven malignancies harboring active site mutations.