3560 Background: The role of immunotherapy in the treatment of pMMR/MSS metastatic CRC is not established. A Japanese phase 1b trial in this setting showed the combination of regorafenib (multikinase inhibitor with immunomodulatory activity) plus nivolumab (anti PD-1) had encouraging activity and manageable safety (Fukuoka, 2020). This study further assessed the safety and efficacy of this combination. Methods: Patients (pts) from the US aged ≥18 years who progressed on/were intolerant to standard chemotherapy were enrolled. Regorafenib was given orally, once daily in 28-day (D) cycles (21D on/7D off) plus IV nivolumab 480 mg on D1. Regorafenib starting dose was 80 mg; if well tolerated, it could be escalated to 120 mg in Cycle 2. Primary endpoint was overall response rate (ORR; RECIST 1.1); secondary aims included disease control rate (DCR), overall survival (OS), progression-free survival (PFS), and safety (NCI-CTCAE v5.0 grade). Biomarker analysis was exploratory. Results: 70 pts (59% male) started treatment. At baseline, median age was 57 years (range 34–85), ECOG PS 0/1 was 51%/49%, 67% had liver metastases (mets), and the primary tumor site was right-sided colon in 36% and rectum in 17%. Median number of cycles was 3.0 (range 1–13); 41% of pts escalated regorafenib to 120 mg. Five pts (7.1%) had a partial response (PR) lasting ≥16 weeks (wks) and 22 (31.4%) had stable disease (SD); pts without liver mets had a higher ORR (21.7%). In pts with tumor samples (n = 40), higher baseline expression (IHC) of cytotoxic T cells (CD3+/CD8+/GranzymeB+), Tregs (FoxP3+), and macrophages (CD68+) trended with clinical benefit (PR/SD ≥16 wks/PFS); pts with liver mets had lower expression. Lower plasma levels of biomarkers of vascular biology (e.g. VEGF-D, Ang-2, VWF) trended with longer PFS. Grade (Gr) 3 treatment-emergent adverse events (TEAEs) occurred in 53% of pts and Gr 4 in 10%. Three pts had a Gr 5 TEAE: n = 1 related to the combination (sepsis); n = 1 related to nivolumab only by investigator (sepsis); n = 1 unrelated to treatment (respiratory failure). Most common Gr 3/4 TEAEs: maculopapular rash (14%), fatigue (7%), pneumonia (6%), increased bilirubin (6%). Conclusions: Combination treatment with regorafenib (up to 120 mg/day) and nivolumab (480 mg every 28D) has manageable safety. Efficacy of this combination in the North American population did not emulate results in the Japanese population. Absence of liver mets and expression of specific biomarkers indicate a better response and may warrant further analysis. Clinical trial information: NCT04126733. [Table: see text]

SummaryVenous thromboembolism (VTE)‐BLEED, a decision tool for predicting major bleeding during chronic anticoagulation for VTE has not yet been validated in practice‐based conditions. We calculated the prognostic indices of VTE‐BLEED for major bleeding after day 30 and day 90, as well as for recurrent VTE and all‐cause mortality, in 4457 patients enrolled in the international, prospective XALIA study. The median at‐risk time was 190 days (interquartile range 106–360). The crude hazard ratio (HR) for major bleeding after day 30 was 2·6 [95% confidence interval (CI) 1·3–5·2] and the treatment‐adjusted HR was 2·3 (95% CI 1·1–4·5) for VTE‐BLEED high (versus low) risk patients: the corresponding values for major bleeding after day 90 were 3·8 (95% CI 1·6–9·3) and 3·2 (95% CI 1·3–7·7), respectively. The predictive value of VTE‐BLEED was similar in selected patients with unprovoked VTE or those treated with rivaroxaban. High VTE‐BLEED score was associated with higher incidence of all‐cause mortality (treatment‐adjusted HR 11, 95% CI 4·8–23), but not evidently with recurrent VTE (treatment‐adjusted HR 1·5; 95% CI 0·85–2·7). These results confirm the predictive value of VTE‐BLEED in practice‐based data in patients treated with rivaroxaban or conventional anticoagulation, supporting the hypothesis that VTE‐BLEED may be useful for making management decisions on the duration of anticoagulant therapy.

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TPS3180 Background: Oncogenic neuregulin 1 ( NRG1) gene fusions occur in ̃0.2% of solid tumors overall and in up to 31% of cases of invasive mucinous lung adenocarcinoma [Laskin et al. Ann Oncol. 2020;31(12):1693–1703; Cadranel et al. Oncologist. 2021;26(1):7–16]. NRG1 fusion proteins provide an extracellular anchor for the epidermal growth factor (EGF) domain of NRG1 to bind to ErbB3 (HER3), leading to HER3 heterodimerization and activation of downstream signaling pathways, resulting in oncogenesis. Afatinib, an irreversible pan-ErbB tyrosine kinase inhibitor, represents a potential treatment for NRG1-fusion positive ( NRG1+) tumors. This study aims to examine the safety and efficacy of afatinib in patients with NRG1+ solid tumors, for which no authorized targeted therapy exists. Methods: This prospective, decentralized, US study (NCT05107193) will include 40 evaluable patients aged ≥18 years. Participating molecular test providers across the USA will identify eligible fusions in the course of routine diagnostic assays. When a patient with an NRG1 fusion is identified, participating test providers will notify the treating physician of the study as a treatment option for the patient. Patients’ primary oncologists will then contact the trial sponsor to confirm patient eligibility. Once approved by the central Institutional Review Board, patients will receive afatinib on a single-patient protocol basis, until disease progression or treatment is no longer tolerated. The recommended dosage per SmPC is 40 mg orally QD. Patients will be screened and enrolled into the study at their existing point-of-care setting. Inclusion criteria include a histologically or cytologically confirmed diagnosis of an advanced, unresectable/metastatic, non-hematologic malignancy with an NRG1 fusion, evaluable per RECIST 1.1. Any coding gene as the NRG1 fusion partner is permitted. Fusion status will be confirmed prospectively by a contracted molecular test provider. Exclusion criteria include prior systemic anti-cancer therapy or investigational drug within 14 days or 5 half-lives (whichever is shorter) of the start of afatinib treatment; an actionable driver mutation other than NRG1 fusion for which FDA-approved targeted therapy is available; and prior treatment with an ErbB-targeted therapy. The primary endpoint of the study is confirmed objective response (OR) by independent central review per RECIST 1.1, defined as best overall response of either complete response or partial response and analysed as the proportion of patients with an OR. The key secondary endpoint is duration of response, defined as the time from the first documented OR to progression or death. Secondary endpoints include time to OR and disease control per investigator assessment. Safety will also be assessed. The study is open for recruitment. Clinical trial information: NCT05107193.

In this study, a new method of enhancing heat transfer in heated channels with purely natural convection flow is presented. Blunt bodies which serve as vortex promoters are introduced into the channel, leading to Kármán vortex streets. Vortex shedding behind cylinders and other blunt bodies leads to a convective mixing of the flow, bringing cooler fluid from the center of the channel to the heated walls. Consequently, the temperature gradient is increased and by that the heat transfer. The purpose of this work is investigating a parameter field in order to identify optimal geometrical parameters for maximizing heat transfer in heated vertical channels. This is done without adding any active mechanical devices for forced convection, but instead by passive means only, meaning cylinders in particular. A parameter study comprising geometrical degrees of freedom like diameter and position of the vortex promoting bodies and different wall temperatures is performed numerically, indicating a heat transfer enhancement of up to 47.4% compared to the reference case without vortex promoters. The CFD results are compared to heat delivery measurements and visualization data.