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Schwann cells form basal laminae (BLs) containing laminin-2 (Ln-2; heterotrimer [alpha]2[beta]1[gamma]1) and Ln-8 ([alpha]4[beta]1[gamma]1). Loss of Ln-2 in humans and mice carrying [alpha]2-chain mutations prevents developing Schwann cells from fully defasciculating axons, resulting in partial amyelination. The principal pathogenic mechanism is thought to derive from structural defects in Schwann cell BLs, which Ln-2 scaffolds. However, we found loss of Ln-8 caused partial amyelination in mice without affecting BL structure or Ln-2 levels. Combined Ln-2/Ln-8 deficiency caused nearly complete amyelination, revealing Ln-2 and -8 together have a dominant role in defasciculation, and that Ln-8 promotes myelination without BLs. Transgenic Ln-10 ([alpha]5[beta]1[gamma]1) expression also promoted myelination without BL formation. Rather than BL structure, we found Ln-2 and -8 were specifically required for the increased perinatal Schwann cell proliferation that attends myelination. Purified Ln-2 and -8 directly enhanced in vitro Schwann cell proliferation in collaboration with autocrine factors, suggesting Lns control the onset of myelination by modulating responses to mitogens in vivo.

Supplemental digital content is available in the text. Objective: This exploratory analysis evaluated the incidence of adverse events (AEs) by folate receptor (FR) status in the randomized, multicenter, open-label PRECEDENT study in women with platinum-resistant ovarian cancer receiving pegylated liposomal doxorubicin (PLD) ± the small-molecule drug conjugate vintafolide. Methods: Women 18 years or older with platinum-resistant ovarian cancer were randomized 2:1 to vintafolide (2.5 mg intravenously, 3 times per week, weeks 1 and 3, every 28 days) + PLD (50 mg/m2 intravenously, day 1, every 28 days) or PLD alone (same dose/schedule). The expression of functionally active FR was evaluated by single-photon emission computed tomography with etarfolatide. Patients were categorized according to FR positivity: patients with all target lesions positive for FR expression (FR 100%), patients with 1 or more but not all target lesions positive for FR expression (FR 10%–90%), and patients with all lesions negative for FR expression (FR 0%). Results: Data on FR status were available for 94 patients: 38 were FR 100%, 36 were FR 10% to 90%, and 20 were FR 0%. Across all FR subgroups, the duration of treatment was longer, and the number of cycles was higher in combination-therapy arms than PLD-alone arms. Although the frequency of AEs was relatively consistent across subgroups, the FR 100% subgroup had a higher incidence of patients with at least 1 AE for combination therapy versus PLD alone. No surprising safety signals were shown according to FR status. The incidence of grade 3 or 4 treatment-emergent drug-related AEs was generally low across all FR subgroups and treatment arms. Conclusions: This exploratory analysis suggests that FR status does not influence the AE profile of vintafolide + PLD combination therapy or PLD alone in patients with platinum-resistant ovarian cancer. Future a priori analyses in larger populations are needed to confirm these findings. [ABSTRACT FROM AUTHOR]

Biallelic mutations in the neurofibromatosis 2 (NF2) gene are linked to schwannoma and meningtoma tumorigenesis. Cells with NF2 mutations exhibit elevated levels of phosphorylated extracellular signal-regulated kinase (ERK) and aberrant cell-cell and cell-matrix contacts. The NF2 gene product, merlin, associates with adherens junction protein complexes, suggesting that part of its function as a tumor suppressor involves regulating cell junctions. Here, we find that a novel PDZ protein, called erbin, binds directly to the merlin-binding partner, EBP0, and regulates adherens junction dissociation through a MAP kinase-dependent mechanism. Reducing erbin expression using a targeted siRNA in primary cultures of Schwann cells results in altered cell-cell interactions, disruption of E-cadherin adherens junctions, increased cell proliferation, and elevated levels of phosphorylated ERK, all phenotypes observed in cells that lack merlin. Reduction of erbin expression also results in the dissociation of merlin from adherens junction proteins and an increase in the levels of phosphorylated merlin. These phenotypes can be rescued if cells with reduced levels of erbin are treated with a pharmacological inhibitor of ERK kinase. Collectively, these data indicate that erbin regulates MAP kinase activation in Schwann cells and suggest that erbin links merlin to both adherens junction protein complexes and the MAP kinase signaling pathway. [ABSTRACT FROM AUTHOR]

GAS6 and AXL are expressed in high-grade serous ovarian cancer but not in normal ovarian tissue. AVB-500, a novel high affinity Fc-sAXL fusion protein, binds GAS6 preventing AXL signaling. This Phase 1b study (NCT03639246) evaluated safety, efficacy, and exploratory predictive markers of AVB-500 combined with paclitaxel (PAC) or pegylated liposomal doxorubicin (PLD) in patients with platinum-resistant ovarian cancer (PROC), and used a model informed drug development (MIDD) approach for identification of the recommended phase 2 dose (RP2D). Eligible patients received AVB-500 at 10, 15, or 20 mg/kg IV q2wk combined with PAC (n = 23) or PLD (n = 30). Patients were treated until progression or unacceptable toxicity. All were followed for survival. No dose limiting toxicities were observed and serum GAS6 was completely suppressed across the three dose levels evaluated. AVB-500 + PAC yielded better clinical activity than AVB-500 + PLD with an ORR of 34.8% (8/23, 2 complete responses) and median DoR, PFS, and OS of 7.0, 3.1, and 10.3 months, respectively. Subgroup analyses showed AVB-500 + PAC patients who had no prior bevacizumab or whose AVB-500 trough levels were >13.8 mg/L exhibited the best clinical response. The ORR and median PFS and OS in patients with these characteristics were ≥50%, ≥7.5 months, and ≥19 months, respectively. Given AVB-500 nor the combination with chemotherapy was expected to cause DLTs, the RP2D of AVB-500 was 15 mg/kg identified using an MIDD approach. AVB-500 was well-tolerated in combination with PAC or PLD and contributed to the clinical activity of PAC in PROC patients. Subgroup analyses identified a population of PROC patients who may benefit the most from AVB-500 treatment, which will be further assessed in an ongoing Phase 3 PROC trial. • The combination of AVB-500 plus chemotherapy was safe and tolerable with no DLTs identified. • At the AVB-500 RP2D (15 mg/kg), AVB-500+PAC demonstrated better clinical activity than AVB-500+PLD. • Patients with no prior bevacizumab had greater clinical response than those with prior bevacizumab and historical control. • An exposure-response relationship was identified for AVB-500 trough levels >13.8 mg/L exhibiting greater clinical response. • A pretreatment serum biomarker may identify patients who benefit from AVB-500 in combination with chemotherapy. [ABSTRACT FROM AUTHOR]

Background: Few effective second-line treatments exist for women with recurrent or metastatic cervical cancer. Accordingly, we aimed to evaluate the efficacy and safety of tisotumab vedotin, a tissue factor-directed antibody-drug conjugate, in this patient population.Methods: This multicentre, open-label, single-arm, phase 2 study was done across 35 academic centres, hospitals, and community practices in Europe and the USA. The study included patients aged 18 years or older who had recurrent or metastatic squamous cell, adenocarcinoma, or adenosquamous cervical cancer; disease progression on or after doublet chemotherapy with bevacizumab (if eligible by local standards); who had received two or fewer previous systemic regimens for recurrent or metastatic disease; had measurable disease based on Response Evaluation Criteria in Solid Tumors (RECIST; version 1.1); and had an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients received 2·0 mg/kg (up to a maximum of 200 mg) tisotumab vedotin intravenously once every 3 weeks until disease progression (determined by the independent review committee) or unacceptable toxicity. The primary endpoint was confirmed objective response rate based on RECIST (version 1.1), as assessed by the independent review committee. Activity and safety analyses were done in patients who received at least one dose of the drug. This study is ongoing with recruitment completed and is registered with ClinicalTrials.gov, NCT03438396.Findings: 102 patients were enrolled between June 12, 2018, and April 11, 2019; 101 patients received at least one dose of tisotumab vedotin. Median follow-up at the time of analysis was 10·0 months (IQR 6·1-13·0). The confirmed objective response rate was 24% (95% CI 16-33), with seven (7%) complete responses and 17 (17%) partial responses. The most common treatment-related adverse events included alopecia (38 [38%] of 101 patients), epistaxis (30 [30%]), nausea (27 [27%]), conjunctivitis (26 [26%]), fatigue (26 [26%]), and dry eye (23 [23%]). Grade 3 or worse treatment-related adverse events were reported in 28 (28%) patients and included neutropenia (three [3%] patients), fatigue (two [2%]), ulcerative keratitis (two [2%]), and peripheral neuropathies (two [2%] each with sensory, motor, sensorimotor, and neuropathy peripheral). Serious treatment-related adverse events occurred in 13 (13%) patients, the most common of which included peripheral sensorimotor neuropathy (two [2%] patients) and pyrexia (two [2%]). One death due to septic shock was considered by the investigator to be related to therapy. Three deaths unrelated to treatment were reported, including one case of ileus and two unknown causes.Interpretation: Tisotumab vedotin showed clinically meaningful and durable antitumour activity with a manageable and tolerable safety profile in women with previously treated recurrent or metastatic cervical cancer. Given the poor prognosis for this patient population and the low activity of current therapies in this setting, tisotumab vedotin, if approved, would represent a new treatment for women with recurrent or metastatic cervical cancer.Funding: Genmab, Seagen, Gynaecologic Oncology Group, and European Network of Gynaecological Oncological Trial Groups. [ABSTRACT FROM AUTHOR]

Background: In the phase 3 KEYNOTE-024 trial, treatment with pembrolizumab conferred longer progression-free survival than did platinum-based therapy in patients with treatment-naive, advanced non-small-cell lung cancer (NSCLC) with a programmed cell death-ligand 1 (PD-L1) tumour proportion score of 50% or greater (PD-L1-positive). Here we report the prespecified exploratory endpoint of pembrolizumab versus chemotherapy on patient-reported outcomes (PROs).Methods: In this multicentre, international, randomised, open-label, phase 3 trial, we recruited patients with treatment-naive, stage IV NSCLC in 102 sites in 16 countries. Eligible patients had measurable disease (per RECIST version 1.1) and an Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. Patients were randomly assigned (1:1) via an interactive voice response system and integrated web response system to receive either pembrolizumab 200 mg every 3 weeks (35 cycles) or investigator-choice platinum-doublet chemotherapy (4-6 cycles or until documented disease progression or unacceptable toxicity). Randomisation was stratified according to geography, ECOG performance status, and histology. PROs were assessed at day 1 of cycles 1-3, every 9 weeks thereafter, at the treatment discontinuation visit, and at the 30-day safety assessment visit using the European Organisation for the Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 items (QLQ-C30), the EORTC Quality of Life Questionnaire Lung Cancer 13 items (QLQ-LC13), and the European Quality of Life 5 Dimensions-3 Level (EQ-5D-3L) questionnaire. The key exploratory PRO endpoints (analysed for all patients who received at least one dose of study treatment and completed at least one PRO instrument at at least one timepoint) were baseline-to-week-15 change in the QLQ-C30 global health status (GHS)/quality-of-life (QOL) score and time to deterioration of the composite of cough, chest pain, and dyspnoea in the QLQ-LC13. This study is registered with ClinicalTrials.gov, number NCT02142738, and is ongoing but no longer enrolling patients.Findings: Between Sept 19, 2014, and Oct 29, 2015, 305 patients were randomly assigned to pembrolizumab (n=154) or chemotherapy (n=151). Three patients in each group did not complete any PRO instruments at any timepoints, and so 299 patients were included in the full analysis set. Of these patients, one in each group did not complete any PRO instruments before week 15, and so were not included in analyses of change from baseline to week 15. PRO compliance was greater than 90% at baseline and approximately 80% at week 15 for both groups. Least-squares mean baseline-to-week-15 change in QLQ-C30 GHS/QOL score was 6·9 (95% CI 3·3 to 10·6) for pembrolizumab and -0·9 (-4·8 to 3·0) for chemotherapy, for a difference of 7·8 (2·9 to 12·8; two-sided nominal p=0·0020). Fewer pembrolizumab-treated patients had deterioration in the QLQ-LC13 composite endpoint than did chemotherapy-treated patients (46 [31%] of 151 patients vs 58 [39%] of 148 patients). Time to deterioration was longer with pembrolizumab than with chemotherapy (median not reached [95% CI 8·5 to not reached] vs 5·0 months [3·6 to not reached]; hazard ratio 0·66, 95% CI 0·44-0·97; two-sided nominal p=0·029).Interpretation: Pembrolizumab improves or maintains health-related QOL compared with that for chemotherapy, and might represent a new first-line standard of care for PD-L1-expressing, advanced NSCLC.Funding: Merck & Co. [ABSTRACT FROM AUTHOR]

Background: Pembrolizumab is a humanized monoclonal antibody against programmed death 1 (PD-1) that has antitumor activity in advanced non-small-cell lung cancer (NSCLC), with increased activity in tumors that express programmed death ligand 1 (PD-L1).Methods: In this open-label, phase 3 trial, we randomly assigned 305 patients who had previously untreated advanced NSCLC with PD-L1 expression on at least 50% of tumor cells and no sensitizing mutation of the epidermal growth factor receptor gene or translocation of the anaplastic lymphoma kinase gene to receive either pembrolizumab (at a fixed dose of 200 mg every 3 weeks) or the investigator's choice of platinum-based chemotherapy. Crossover from the chemotherapy group to the pembrolizumab group was permitted in the event of disease progression. The primary end point, progression-free survival, was assessed by means of blinded, independent, central radiologic review. Secondary end points were overall survival, objective response rate, and safety.Results: Median progression-free survival was 10.3 months (95% confidence interval [CI], 6.7 to not reached) in the pembrolizumab group versus 6.0 months (95% CI, 4.2 to 6.2) in the chemotherapy group (hazard ratio for disease progression or death, 0.50; 95% CI, 0.37 to 0.68; P<0.001). The estimated rate of overall survival at 6 months was 80.2% in the pembrolizumab group versus 72.4% in the chemotherapy group (hazard ratio for death, 0.60; 95% CI, 0.41 to 0.89; P=0.005). The response rate was higher in the pembrolizumab group than in the chemotherapy group (44.8% vs. 27.8%), the median duration of response was longer (not reached [range, 1.9+ to 14.5+ months] vs. 6.3 months [range, 2.1+ to 12.6+]), and treatment-related adverse events of any grade were less frequent (occurring in 73.4% vs. 90.0% of patients), as were grade 3, 4, or 5 treatment-related adverse events (26.6% vs. 53.3%).Conclusions: In patients with advanced NSCLC and PD-L1 expression on at least 50% of tumor cells, pembrolizumab was associated with significantly longer progression-free and overall survival and with fewer adverse events than was platinum-based chemotherapy. (Funded by Merck; KEYNOTE-024 ClinicalTrials.gov number, NCT02142738 .). [ABSTRACT FROM AUTHOR]

Purpose: Tissue factor (TF) is a potential target in cervical cancer, as it is frequently highly expressed and associated with poor prognosis. Tisotumab vedotin, a first-in-class investigational antibody-drug conjugate targeting TF, has demonstrated encouraging activity in solid tumors. Here we report data from the cervical cancer cohort of innovaTV 201 phase I/II study (NCT02001623)., Patients and Methods: Patients with recurrent or metastatic cervical cancer received tisotumab vedotin 2.0 mg/kg every 3 weeks until progressive disease, unacceptable toxicity, or consent withdrawal. The primary objective was safety and tolerability. Secondary objectives included antitumor activity., Results: Of the 55 patients, 51% had received ≥2 prior lines of treatment in the recurrent or metastatic setting; 67% had prior bevacizumab + doublet chemotherapy. Fifty-one percent of patients had squamous cell carcinoma. The most common grade 3/4 treatment-emergent adverse events (AEs) were anemia (11%), fatigue (9%), and vomiting (7%). No grade 5 treatment-related AEs occurred. Investigator-assessed confirmed objective response rate (ORR) was 24% [95% confidence interval (CI): 13%-37%]. Median duration of response (DOR) was 4.2 months (range: 1.0 + -9.7); four patients responded for >8 months. The 6-month progression-free survival (PFS) rate was 29% (95% CI: 17%-43%). Independent review outcomes were comparable, with confirmed ORR of 22% (95% CI: 12%-35%), median DOR of 6.0 months (range: 1.0 + -9.7), and 6-month PFS rate of 40% (95% CI: 24%-55%). Tissue factor expression was confirmed in most patients; no significant association with response was observed., Conclusions: Tisotumab vedotin demonstrated a manageable safety profile and encouraging antitumor activity in patients with previously treated recurrent or metastatic cervical cancer., (©2019 American Association for Cancer Research.)