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The epicardium, a mesothelial cell tissue that encompasses vertebrate hearts, supports heart regeneration after injury through paracrine effects and as a source of multipotent progenitors. However, the progenitor state in the adult epicardium has yet to be defined. Through single-cell RNA-sequencing of isolated epicardial cells from uninjured and regenerating adult zebrafish hearts, we define the epithelial and mesenchymal subsets of the epicardium. We further identify a transiently activated epicardial progenitor cell (aEPC) subpopulation marked by ptx3a and col12a1b expression. Upon cardiac injury, aEPCs emerge from the epithelial epicardium, migrate to enclose the wound, undergo epithelial-mesenchymal transition (EMT), and differentiate into mural cells and pdgfra + hapln1a + mesenchymal epicardial cells. These EMT and differentiation processes are regulated by the Tgfβ pathway. Conditional ablation of aEPCs blocks heart regeneration through reduced nrg1 expression and mesenchymal cell number. Our findings identify a transient progenitor population of the adult epicardium that is indispensable for heart regeneration and highlight it as a potential target for enhancing cardiac repair. The epicardium supports heart regeneration, though precisely how is unclear. Here the authors define an activated epicardial progenitor population as the source of essential cell types and paracrine factors for successful heart regeneration in zebrafish.

Locally advanced or metastatic urothelial carcinoma is generally incurable and has scarce treatment options, especially for cisplatin-ineligible patients previously treated with PD-1 or PD-L1 therapy. Enfortumab vedotin is an antibody–drug conjugate directed at Nectin-4, a protein highly expressed in urothelial carcinoma. We aimed to evaluate the efficacy and safety of enfortumab vedotin in the post-immunotherapy setting in cisplatin-ineligible patients. EV-201 is a multicentre, single-arm, phase 2 study of enfortumab vedotin in patients with locally advanced or metastatic urothelial carcinoma previously treated with PD-1 or PD-L1 inhibitors. Cohort 2 included adults (aged ≥18 years) with an Eastern Cooperative Oncology Group performance status score of 2 or less who were considered ineligible for cisplatin at enrolment and who had not received platinum-containing chemotherapy in the locally advanced or metastatic setting. Enfortumab vedotin was given intravenously at a dose of 1·25 mg/kg on days 1, 8, and 15 of every 28-day cycle. The primary endpoint was confirmed objective response rate per Response Evaluation Criteria in Solid Tumours version 1.1 assessed by blinded independent central review. Efficacy and safety were analysed in all patients who received at least one dose of enfortumab vedotin. EV-201 is an ongoing study and the primary analysis is complete. This study is registered with Clinicaltrials.gov, NCT03219333. Between Oct 8, 2017, and Feb 11, 2020, 91 patients were enrolled at 40 sites globally, of whom 89 received treatment. Median follow-up was 13·4 months (IQR 11·3–18·9). At data cutoff (Sept 8, 2020), the confirmed objective response rate was 52% (46 of 89 patients; 95% CI 41–62), with 18 (20%) of 89 patients achieving a complete response and 28 (31%) achieving a partial response. 49 (55%) of 89 patients had grade 3 or worse treatment-related adverse events. The most common grade 3 or 4 treatment-related adverse events were neutropenia (eight [9%] patients), maculopapular rash (seven [8%] patients), and fatigue (six [7%] patients). Treatment-related serious adverse events occurred in 15 (17%) patients. Three (3%) patients died due to acute kidney injury, metabolic acidosis, and multiple organ dysfunction syndrome (one [1%] each) within 30 days of first dose and these deaths were considered by the investigator to be related to treatment; a fourth death from pneumonitis occurred more than 30 days after the last dose and was also considered to be related to treatment. Treatment with enfortumab vedotin was tolerable and confirmed responses were seen in 52% of cisplatin-ineligible patients with locally advanced or metastatic urothelial carcinoma who were previously treated with PD-1 or PD-L1 inhibitors. These patients have few treatment options, and enfortumab vedotin could be a promising new therapy for a patient population with a high unmet need. Astellas Pharma Global Development and Seagen.

Metastatic castration-resistant prostate cancer (mCRPC) remains a terminal diagnosis with an aggressive disease course despite currently approved therapeutics. The recent successful development of poly ADP-ribose polymerase (PARP) inhibitors for patients with mCRPC and mutations in DNA damage repair genes has added to the treatment armamentarium and improved personalized treatments for prostate cancer. Other promising therapeutic agents currently in clinical development include the radiotherapeutic 177-lutetium-prostate-specific membrane antigen (PSMA)-617 targeting PSMA-expressing prostate cancer and combinations of immunotherapy with currently effective treatment options for prostate cancer. Herein, we have highlighted the progress in systemic treatments for mCRPC and the promising agents currently in ongoing clinical trials.

BackgroundCheckMate 920 (NCT02982954) is a multicohort, phase 3b/4 clinical trial of nivolumab plus ipilimumab treatment in predominantly US community-based patients with previously untreated advanced renal cell carcinoma (RCC) and clinical features mostly excluded from phase 3 trials. We report safety and efficacy results from the advanced non-clear cell RCC (nccRCC) cohort of CheckMate 920.MethodsPatients with previously untreated advanced/metastatic nccRCC, Karnofsky performance status ≥70%, and any International Metastatic Renal Cell Carcinoma Database Consortium risk received up to four doses of nivolumab 3 mg/kg plus ipilimumab 1 mg/kg every 3 weeks followed by nivolumab 480 mg every 4 weeks for ≤2 years or until disease progression/unacceptable toxicity. The primary endpoint was incidence of grade ≥3 immune-mediated adverse events (AEs) within 100 days of last dose of study drug. Key secondary endpoints included objective response rate (ORR), progression-free survival (PFS; both investigator-assessed), time to response (TTR), and duration of response (DOR), all using RECIST V.1.1. Overall survival (OS) was exploratory.ResultsFifty-two patients with nccRCC (unclassified histology, 42.3%; papillary, 34.6%; chromophobe, 13.5%; translocation-associated, 3.8%; collecting duct, 3.8%; renal medullary, 1.9%) received treatment. With 24.1 months minimum study follow-up, median duration of therapy (range) was 3.5 (0.0–25.8) months for nivolumab and 2.1 (0.0–3.9) months for ipilimumab. Median (range) number of doses received was 4.5 (1–28) for nivolumab and 4.0 (1–4) for ipilimumab. Grade 3–4 immune-mediated AEs were diarrhea/colitis (7.7%), rash (5.8%), nephritis and renal dysfunction (3.8%), hepatitis (1.9%), adrenal insufficiency (1.9%), and hypophysitis (1.9%). No grade 5 immune-mediated AEs occurred. ORR (n=46) was 19.6% (95% CI 9.4 to 33.9). Two patients achieved complete response (papillary, n=1; unclassified, n=1), seven achieved partial response (papillary, n=4; unclassified, n=3), and 17 had stable disease. Median TTR was 2.8 (range 2.1–14.8) months. Median DOR was not reached (range 0.0+−27.8+); eight of nine responders remain without reported progression. Median PFS (n=52) was 3.7 (95% CI 2.7 to 4.6) months. Median OS (n=52) was 21.2 (95% CI 16.6 to not estimable) months.ConclusionsNivolumab plus ipilimumab for previously untreated advanced nccRCC showed no new safety signals and encouraging antitumor activity.Trial registration numberNCT02982954.

Unlike its mammalian counterpart, the adult zebrafish heart is able to fully regenerate after severe injury. One of the most important events during the regeneration process is cardiomyocyte proliferation, which results in the replacement of lost myocardium. Growth factors that induce cardiomyocyte proliferation during zebrafish heart regeneration remain to be identified. Signaling pathways important for heart development might be reutilized during heart regeneration. IGF2 was recently shown to be important for cardiomyocyte proliferation and heart growth during mid-gestation heart development in mice, although its role in heart regeneration is unknown. We found that expression of igf2b was upregulated during zebrafish heart regeneration. Following resection of the ventricle apex, igf2b expression was detected in the wound, endocardium and epicardium at a time that coincides with cardiomyocyte proliferation. Transgenic zebrafish embryos expressing a dominant negative form of Igf1 receptor (dn-Igf1r) had fewer cardiomyocytes and impaired heart development, as did embryos treated with an Igf1r inhibitor. Moreover, inhibition of Igf1r signaling blocked cardiomyocyte proliferation during heart development and regeneration. We found that Igf signaling is required for a subpopulation of cardiomyocytes marked by gata4:EGFP to contribute to the regenerating area. Our findings suggest that Igf signaling is important for heart development and myocardial regeneration in zebrafish.

BackgroundLow-density lipoprotein receptor-related protein 1b (encoded by LRP1B) is a putative tumor suppressor, and preliminary evidence suggests LRP1B-mutated cancers may have improved outcomes with immune checkpoint inhibitors (ICI).MethodsWe conducted a multicenter, retrospective pan-cancer analysis of patients with LRP1B alterations treated with ICI at Duke University, Johns Hopkins University (JHU) and University of Michigan (UM). The primary objective was to assess the association between overall response rate (ORR) to ICI and pathogenic or likely pathogenic (P/LP) LRP1B alterations compared with LRP1B variants of unknown significance (VUS). Secondary outcomes were the associations with progression-free survival (PFS) and overall survival (OS) by LRP1B status.ResultsWe identified 101 patients (44 Duke, 35 JHU, 22 UM) with LRP1B alterations who were treated with ICI. The most common tumor types by alteration (P/LP vs VUS%) were lung (36% vs 49%), prostate (9% vs 7%), sarcoma (5% vs 7%), melanoma (9% vs 0%) and breast cancer (3% vs 7%). The ORR for patients with LRP1B P/LP versus VUS alterations was 54% and 13%, respectively (OR 7.5, 95% CI 2.9 to 22.3, p=0.0009). P/LP LRP1B alterations were associated with longer PFS (HR 0.42, 95% CI 0.26 to 0.68, p=0.0003) and OS (HR 0.62, 95% CI 0.39 to 1.01, p=0.053). These results remained consistent when excluding patients harboring microsatellite instability (MSI) and controlling for tumor mutational burden (TMB).ConclusionsThis multicenter study shows significantly better outcomes with ICI therapy in patients harboring P/LP versus VUS LRP1B alterations, independently of TMB/MSI status. Further mechanistic and prospective validation studies are warranted.

Neoadjuvant cisplatin-based chemotherapy is standard of care for muscle-invasive bladder cancer (MIBC). Immune checkpoint inhibition (ICI) alone, and ICI in combination with chemotherapy, have demonstrated promising pathologic response (

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