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Dysregulation of MET signaling has been implicated in tumorigenesis and metastasis. ARGX-111 combines complete blockade of this pathway with enhanced tumor cell killing and was investigated in 24 patients with MET-positive advanced cancers in a phase 1b study at four dose levels (0.3–10 mg/kg). ARGX-111 was well tolerated up to 3 mg/kg (MTD). Anti-tumor activity was observed in nearly half of the patients (46%) with a mean duration of treatment of 12 weeks. NHance® mutations in the Fc of ARGX-111 increased affinity for the neonatal Fc receptor (FcRn) at acidic pH, stimulating transcytosis across FcRn-expressing cells and radiolabeled ARGX-111 accumulated in lymphoid tissues, bone and liver, organs expressing FcRn at high levels in a biodistribution study using human FcRn transgenic mice. In line with this, we observed, in a patient with MET-amplified (>10 copies) gastric cancer, diminished metabolic activity in multiple metastatic lesions in lymphoid and bone tissues by 18F-FDG-PET/CT after two infusions with 0.3 mg/kg ARGX-111. When escalated to 1 mg/kg, a partial response was reached. Furthermore, decreased numbers of CTC (75%) possibly by the enhanced tumor cell killing witnessed the modes of action of the drug, warranting further clinical investigation of ARGX-111., SCOPUS: ar.j, info:eu-repo/semantics/published

Acute myeloid leukemia (AML) is driven by leukemia stem cells (LSCs) that resist conventional chemotherapy and are the major cause of relapse1,2. Hypomethylating agents (HMAs) are the standard of care in the treatment of older or unfit patients with AML, but responses are modest and not durable3-5. Here we demonstrate that LSCs upregulate the tumor necrosis factor family ligand CD70 in response to HMA treatment resulting in increased CD70/CD27 signaling. Blocking CD70/CD27 signaling and targeting CD70-expressing LSCs with cusatuzumab, a human αCD70 monoclonal antibody with enhanced antibody-dependent cellular cytotoxicity activity, eliminated LSCs in vitro and in xenotransplantation experiments. Based on these preclinical results, we performed a phase 1/2 trial in previously untreated older patients with AML with a single dose of cusatuzumab monotherapy followed by a combination therapy with the HMA azacitidine (NCT03030612). We report results from the phase 1 dose escalation part of the clinical trial. Hematological responses in the 12 patients enrolled included 8 complete remission, 2 complete remission with incomplete blood count recovery and 2 partial remission with 4 patients achieving minimal residual disease negativity by flow cytometry at

Summary Background The C-X-C chemokine receptor type 4 (CXCR4)–stromal cell-derived factor-1α (SDF-1α) axis regulates function and trafficking of immune cells and the tumour microenvironment. CXCR4 antagonists have been shown to enhance the activity of different anticancer treatments in preclinical models. We assessed the safety, tolerability, pharmacokinetics, and preliminary phase 1 activity of the CXCR4 antagonist, balixafortide, in combination with eribulin chemotherapy in patients with heavily pretreated, relapsed metastatic breast cancer. Methods This single-arm, dose-escalation, phase 1 trial enrolled patients at 11 sites in Spain and the USA. Eligible patients were women aged 18 years or older who had histologically confirmed HER2-negative metastatic breast cancer, evidence of tumour cell CXCR4 expression, an Eastern Cooperative Oncology Group performance status of 0 or 1, and who had previously received between one and three chemotherapy regimens for metastatic breast cancer, and at least one endocrine therapy if they had hormone receptor-positive disease, unless they were considered unsuitable for endocrine therapy. A standard 3+3 dose-escalation design was used, followed by an expanded cohort at the established maximum tolerated dose or highest dose if no dose-limiting toxicity was observed for the combination. After a treatment-related fatal adverse event in the first cohort who received 21-day cycles of treatment with eribulin and balixafortide, a protocol amendment modified the study design to be done in two parts. Patients enrolled to part 1 received an initial 28-day run-in cycle, with some cohorts receiving de-escalated doses of eribulin plus balixafortide to assess the safety and pharmacokinetics of the combination. The evaluation of part 1 did not confirm any dose-limiting toxicities or eribulin–balixafortide interactions, and therefore part 2 started enrolling patients to receive eribulin at the originally planned dose of 1·4 mg/m 2 on days 2 and 9 of a 21-day cycle and balixafortide from a starting dose of 2 mg/kg with dose increments of 0·5 or 1 mg/kg on days 1–3 and 8–10 of the 21-day cycle. Both drugs were administered as intravenous infusions. All patients were to receive treatment until disease progression or unacceptable toxicity. The primary endpoints were dose-limiting toxicities and adverse events, and the establishment of a maximum tolerated dose or recommended phase 2 dose, and pharmacokinetic parameters. Safety analysis was done in all patients who received at least one dose of study treatment. Analysis of antitumour activity was done in all patients who received at least one full cycle of study treatment. The trial is registered at ClinicalTrials.gov, number NCT01837095, and is closed to accrual. Findings Between Jan 28, 2014, and Oct 4, 2016, 56 patients were enrolled into the trial. No dose-limiting toxicities were confirmed and the maximum tolerated dose was not reached. The highest dose was established as eribulin 1·4 mg/m 2 on days 2 and 9, and balixafortide 5·5 mg/kg on days 1–3 and 8–10 of the 21-day cycle. Objective responses (all partial responses) were observed in 16 (30%; 95% CI 18–44) of 54 patients who were evaluable for antitumour activity. The most common treatment-emergent adverse events of any grade were fatigue (44 [79%] of 56 patients), neutropenia (32 [57%]), infusion-related reactions (27 [48%]), alopecia (26 [46%]), constipation (26 [46%]), and nausea (25 [45%]). Serious adverse events occurred in 21 (38%) of 56 patients, including febrile neutropenia in five (9%) of 56 patients, neutrophil count decrease in two (4%) patients, constipation in two (4%) patients, pneumonia in two (4%) patients, and urinary tract infection in three (5%) patients. Two (4%) of 56 patients died while receiving study treatment; one from septic shock and one from pneumonia. Interpretation The safety and tolerability of balixafortide plus eribulin seems to be similar to that of eribulin or balixafortide monotherapy, and the preliminary activity of the combination seems promising in patients with HER-negative metastatic breast cancer. The results suggest that balixafortide plus eribulin has potential to provide a new therapeutic option in heavily pretreated patients with metastatic breast cancer and warrants further investigation in randomised trials. Funding Polyphor.

Introduction Acute myeloid leukemia (AML) is a heterogenous hematological malignancy driven by leukemia stem cells (LSCs) (Lapidot et al, 1994). LSCs resistant against conventional chemotherapy represent the major cause of relapse. Elderly or unfit AML patients not eligible for intensive chemotherapy are treated in a palliative setting with hypomethylating agents (HMA) or low dose Ara-C, but responses are modest and not durable. The reason for the low efficacy of HMA treatment is their insufficient action on the disease initiating- and -maintaining LSC population (Craddock et al, 2013). We recently demonstrated that CD34+ AML cells (progenitors and LSC) consistently express the tumor necrosis factor family ligand CD70 as well as its receptor CD27 and that cell-autonomous CD70/CD27-signaling propagates the disease (Riether et al. 2017). The aim of the current study was to evaluate whether resistance to HMA treatment can be overcome by combining HMA with an anti-CD70 monoclonal antibody treatment. Experimental design The effect of HMA treatment on the expression of CD70 on primary human CD34+CD38- AML LSCs was determined in vitro cultures and in patients treated with HMA in vivo. The therapeutic potential of targeting CD70-expressing LSCs in presence and absence of HMA was assessed using the anti-CD70 ADCC-optimized monoclonal antibody (mAb), cusatuzumab, and an effector-dead anti-CD70 mAb in colony formation and re-plating assays as well as patient-derived xenograft models (Silence et al, 2014). The clinical relevance of the findings was determined in a clinical phase 1 trial in previously untreated elderly AML patients with a single dose of cusatuzumab monotherapy followed by a combination therapy with the HMA azacitidine (AZA, NCT03030612). Four different dose levels of cusatuzumab (1, 3, 10 and 20 mg/kg Q2W) were studied; AZA was administered at 75 mg/m² for 7 days every 28 days. Results We found that resistance of AML LSCs to HMA treatment is mediated by the up-regulation of the CD70. The up-regulation of CD70 triggered cell-autonomous CD70/CD27 signaling on AML LSCs. Based on these findings we hypothesized that the upregulation of CD70 by HMA may render LSCs more susceptible to CD70-targeting interventions. Targeting CD70-expressing LSCs by a blocking anti-CD70 mAb and the anti-CD70 mAb cusatuzumab, which blocks CD70/CD27-signaling and additionally mediates ADCC and CDC, eradicated LSCs in colony and re-plating assays in vitro and in xenotransplantation experiments in vivo. HMA in combination with blocking αCD70 mAb synergistically reduced LSC numbers in vivo and this was even more efficient when ADCC-enhanced αCD70 mAb cusatuzumab was added in the presence of NK cells. In order to test the hypothesis that targeting CD70 in combination with HMA eliminates LSCs in AML patients, we initiated a phase 1 dose-escalation trial in previously untreated elderly AML patients with a single dose of cusatuzumab monotherapy followed by a combination therapy with azacitidine. No dose-limiting toxicities (DLT) were observed in the dose-escalation phase 1 trial and responses were observed across the dose levels (1-20 mg/kg). A single dose of cusatuzumab reduced bone marrow blasts in just two weeks in all patients on average by 32%. Cusatuzumab monotherapy significantly reduced LSC numbers and frequencies in all patients analyzed in the bone marrow as assessed in limiting dilution colony assays. Single cell sequencing analysis revealed that cusatuzumab induced gene signatures related to myeloid differentiation and apoptosis in LSCs. In combination with azacitidine, cusatuzumab induced CR/CRi in 10 out of 12 patients. Responses were observed at all dose levels of cusatuzumab and median time to response was 3.3 months. Conclusions Blocking CD70/CD27-signaling and targeting CD70-expressing LSCs by the ADCC-optimized mAb, cusatuzumab, eliminated LSCs in vitro and in xenotransplantation experiments. In a phase 1 study promising activity of cusatuzumab in combination with HMA was observed in AML patients, in which translational data indicate that cusatuzumab selectively eliminates CD70-expressing LSCs. Disclosures Van Rompaey: argenx: Employment, Equity Ownership, Patents & Royalties. Moshir:Argenx: Employment, Equity Ownership. Delahaye:argenx: Employment, Equity Ownership. Gandini:Argenx: Employment, Equity Ownership. Erzeel:argenx: Employment, Equity Ownership. Hultberg:Argenx: Employment. Fung:argenx: Consultancy, Equity Ownership. De Haard:Argenx: Employment, Equity Ownership, Patents & Royalties. Leupin:Argenx: Employment, Equity Ownership, Patents & Royalties.

Outcomes in elderly patients with acute myeloid leukemia (AML) are still adverse, as the majority does not qualify for intensive therapy or allogenic stem cell transplantation (ASCT). DNA hypomethylating agents (HMAs) induce remissions and prolong survival in a fraction of these patients. However, overall prognosis remains dismal and all patients progress due to therapy-resistant leukemia stem cells (LSCs). We recently demonstrated that HMAs upregulate the expression of CD70 on primary human AML LSCs, potentially contributing to HMA resistance and that blocking the cell-autonomous CD70/CD27 signaling inhibits proliferation and myeloid differentiation of LSCs and contributes to HMA resistance. Consequently, combining HMA treatment with a blocking αCD70 monoclonal antibody potently reduced colony formation of AML LSCs in vitro and effectively eliminated human AML LCSs in xenograft experiments. Based on these results, we initiated an open-label, non-controlled, non-randomized Phase 1/2 trial combining the HMA azacitidine (AZA) with ARGX-110, a human monoclonal antibody targeting CD70, in newly diagnosed AML patients unfit for intensive chemotherapy (ARGX-110-1601, NCT03030612). Trial design ARGX-110 with optimized antibody-dependent cell-mediated cytotoxicity (ADCC), is administered intravenously at 1, 3, 10 or 20 mg/kg once every two weeks (Q2W), in combination with a standard dose of AZA (75 mg/m² subcutaneously for 7 days every 28 days). A 2-week lead-in of ARGX-110 enables studying the effect of αCD70 antibody monotherapy. Primary objectives in the Phase 1 include determining the maximum tolerated dose of ARGX-110 in combination with AZA and the recommended phase 2 dose (RP2D). Secondary objectives comprise safety, pharmacokinetics and anti-leukemic activity of ARGX-110 alone or in combination with AZA (including overall response rate (ORR), frequencies of LSCs and minimal/measurable residual disease (MRD)). Results The trial is ongoing and as of 16th July 2018, 12 newly diagnosed AML patients were treated in the dose-escalation part of the trial, the results of which will be further updated in December 2018. The median age over the dose cohorts was 75 years (range 64-84) and included intermediate (N=6) and adverse (N=6) ELN risk groups. WHO subtypes were AML with recurrent genetic abnormalities (N=2), MDS-related changes (N=6), AML-NOS (N=3) and therapy-related myeloid neoplasms (N=1). No dose-limiting toxicity was observed and the combination of ARGX-110 with a standard dose of AZA was well tolerated. Hematological toxicities, in line with expected AZA toxicities, were the most frequently reported adverse events (AEs). At the cut-off, the ORR (complete remission [CR] + incomplete recovery [CRi] + partial remission [PR] + morphologic leukemia-free status [MLFS]) was 92% (11/12 patients); among the 11 evaluable subjects, the best response was CR/CRi for 9 patients (82%), 1 patient (9%) reached MLFS, and 1 (9%) PR, with 7 patients still on the trial (median duration on the trial at cut-off was 6.9 months [range: 2-14.4 months]). Significantly, 1 patient reached CR and was discontinued after 5 months to undergo ASCT. Five evaluable patients (45%) achieved MRD negativity by flow cytometry. Molecular MRD negativity was achieved in 3/8 patients with available results, two correlating with flow-MRD negativity. The mean time to response for the first 9 patients was 2.8 months and 3.4 months to reach best response. The 3 patients in the 20 mg/kg cohort did not all reach response at the time of cut-off. Based on pharmacokinetics, safety, and pharmacodynamic data, the RP2D of 10 mg/kg was established. Translational studies assessing LSC frequencies in bone marrow aspirates by limiting dilution colony assays and xenograft experiments revealed that ARGX-110 monotherapy and in combination with AZA significantly reduced LSC frequencies in AML patients. Conclusions ARGX-110 in combination with AZA is well tolerated and leads to a higher ORR compared to historical data for AZA alone. Clinical activity of the combination is observed in different AML subtypes and risk categories. Preliminary data indicate that ARGX-110 alone, and in combination with AZA, efficiently eliminates LSCs. These observations warrant further accelerated investigation of ARGX-110 in combination with AZA in AML patients unfit for intensive therapy. Disclosures Ochsenbein: argenx: Research Funding. Riether:argenx: Research Funding. Bacher:argenx: Research Funding. Höpner:argenx: Research Funding. Hinterbrandner:argenx: Research Funding. Van Rompaey:argenx: Employment. Moshir:argenx: Employment. Delahaye:argenx: Employment. Gandini:argenx: Employment. Erzeel:argenx: Employment. Hultberg:argenx: Employment. Fung:argenx: Consultancy. De Haard:argenx: Employment. Leupin:argenx: Employment.

SummaryWomen with a history of venous thromboembolism (VTE), thrombophilia or both may be at increased risk of thrombosis during pregnancy, but the optimal management strategy is not well defined in clinical guidelines because of limited trial data. A strategy of risk assessment and heparin prophylaxis was evaluated in pregnant women at increased risk of VTE. In a prospective trial (Efficacy of Thromboprophylaxis as an Intervention during Gravidity [EThIG]), 810 pregnant women were assigned to one of three management strategies according to pre-defined risk factors related to history of VTE and thrombophilic profile. Low-risk women (group I), received 50–100 IU dalteparin/ kg body weight/ day for 14 days postpartum, or earlier when additional risk factors occurred. Women at high (group II) or very high risk (group III) received dalteparin from enrolment until six weeks postpartum (50–100 IU and 100–200 IU/ kg/ day, respectively). Objectively confirmed, symptomatic VTE occurred in 5/810 women (0.6%; 95% confidence interval [CI], 0.2 to 1.5%) (group I, 0 of 225; II, 3/469; III, 2/116). The rate of serious bleeding was 3.0% (95 % CI, 1.9 to 4.4%); 1.1% (95 % CI, 0.5 to 2.2%) was possibly dalteparin-related. There was no evidence of heparin- induced thrombocytopenia, one case of osteoporosis, and rates of miscarriage and stillbirth were similar to previous, retrospective studies. Risk-stratified heparin prophylaxis was associated with a low incidence of symptomatic VTE and few clinically important adverse events. Antepartum heparin prophylaxis is, therefore, warranted in pregnant women with idiopathic thrombosis or symptomatic thrombophilia.

Background Long-term maintenance immunosuppression with cyclosporine (CsA) is associated with chronic transplant nephropathy and adverse effects on blood pressure and lipid profile. Several nonrandomized studies suggest that CsA might safely be withdrawn from immunosuppressive regimens containing mycophenolate mofetil (MMF; CellCept). Methods A randomized, controlled study with 187 patients enrolled from 21 centers was conducted to compare CsA withdrawal with ongoing CsA therapy in stable renal transplant recipients receiving a triple-drug immunosuppressive regimen of MMF (2 g/day), CsA (Neoral), and corticosteroids. The primary endpoint was creatinine clearance at 6 months after complete withdrawal. Results In the intent-to-treat population, CsA withdrawal was associated with lower total cholesterol and low-density lipoprotein cholesterol (-0.3 mmol/L, P=0.02; -0.4 mmol/L, P=0.015). There was a trend toward improved creatinine clearance (4.5 mL/min, P=0.16) and serum creatinine (-1 vs. +4 micromol/L, P=0.34). In the per-protocol population, which excluded patients with acute rejections, the improvements in creatinine clearance and serum creatinine were statistically significant (7.5 mL/min, P=0.02; -11 vs. +4 micromol/L, P=0.0003). Reversible acute rejections, the majority of which were mild, occurred in nine CsA withdrawal versus two CsA continuation patients (10.6% vs. 2.4% of each group, P=0.03), with no graft loss. Conclusion Withdrawal of CsA from an MMF-containing triple-drug immunosuppressive regimen improves renal function and lipid profile at the cost of a modest increase in acute rejections, without graft loss.

e14016Background: ARGX-111 is a therapeutic antibody candidate combining three independent MoA: i. blockade of HGF-dependent and -independent MET activity, ii. enhanced ADCC and iii. increased tissue penetration through enhanced FcRn binding. A Phase-I study (NCT02055066) in patients with c-MET-amplified tumors is ongoing. A new hypothesis for depletion of MET-positive MDSCs in the tumor microenvironment is also investigated. Methods: c-MET amplification detected using FISH on tumor biopsies is a prescreening requisite for patient selection in the expansion phase. MDSCs were enumerated by FACS using blood and ascites from patients or tumor and spleen tissue from a mouse CT26 syngeneic tumor model. Results: ARGX-111 dose escalation indicated a favorable safety profile and fixed a 3 mg/kg bi-weekly dose for the safety expansion in c-MET-amplified patients. Efficacy signals were seen in the c-MET-amplified setting [J Clin Oncol 33, 2015 (suppl; abstr 2580)]. FISH screening identified 4% of c-MET-amplified bi...

Women with a history of VTE, thrombophilia or both are at increased risk for VTE during pregnancy, but the optimal management strategy, and the need for thromboprophylaxis is not well defined in clinical guidelines because of limited trial data. The EThIG (Efficacy of Thromboprophylaxis as an Intervention during Gravidity) is a multicenter trial that prospectively enrolled 810 pregnant women at risk of VTE. Women were assigned to one of 3 management strategies: Low risk group I (including women with prior secondary VTE, or asymptomatic thrombophilia) with “watchful waiting” management, and dalteparin prophylaxis postpartum (50–100 IU/kg), or earlier if additional risk factors occurred; high risk group II (e.g. idiopathic VTE or symptomatic thrombophilia) receiving 50–100 IU/kg dalteparin; and very high-risk group III (e.g. acute VTE, prior long-term OAC, symptomatic AT-deficiency or antiphospholipid syndrome), receiving 100–200 IU/kg dalteparin. Primary efficacy outcome measure was symptomatic VTE, main safety outcome measures were haemorrhages, osteoporosis, thromboctopenia and pregnancy outcome. Results (mean ± SD / 95% CI): 810 women (age 30.8±5.4 years, weight 73.6±16.1kg) were enrolled, 28 % in group I, 58 % in II and 14% in III, including 66 women with acute VTE. 60.1% had prior VTE, 75.4% had thrombophilia (42.1 % FV-Leiden, 2.1 % homozygous, 9.5 % FII G20210A, 4.1% PC-, 1 % AT-deficiency; 17.4 % APS). 35.8 % had previous miscarriage, still birth or physical malformation. Comorbid conditions included lupus erythematosus, liver transplantation, ventricular septum defect, paraplegia, hepatitis C, nephrotic syndrome, asthma, chronic haemolytic anaemia, thalassaemia, osteoporosis and thrombocytopaenia. Median treatment initiation was at 17.0 weeks, at 24.0 weeks in group I, 14.5 weeks in group II and 16.0 weeks for group III. Mean daily dose was 66.2 ± 22.5 IU per kg (group I), 76.8 ± 24.1 IU per kg (group II) and 120.0 ± 49.1 IU per kg (group III). Objectively confirmed, symptomatic VTE occurred in 5 of 810 women (0.6%;0.2–1.5%). The rate of serious bleeding was 3.0% (1.9–4.4%), 0.9% (0.3–1.8%) occurred in the antepartum period, 2.1% (1.3–3.4%) peri-partum;1.1% (0.5–2.2%) was possibly heparin-related. There was no evidence of heparin-induced thrombocytopenia, and one case of osteoporosis (fracture of the saccygous bone during delivery). There were 94.4% successful pregnancies, 40 foetuses (4.9%; 3.6–6.7%) were lost due to miscarriage, 7 due to elective termination. Risk-stratified heparin prophylaxis was associated with a low incidence of symptomatic venous thromboembolism and few clinically important adverse events. Antepartum heparin prophylaxis is warranted in pregnant women with prior idiopathic thrombosis or symptomatic thrombophilia.