Clinical results of a phase 1 study of intravesical EG-70 in patients with BCG-unresponsive NMIBC

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Background: enGene is developing non-viral gene therapy platforms to deliver nucleic acids (plasmids) to epithelial mucosal tissues such as urothelium of urinary bladder. EG-70 is a nanoparticle formulation of plasmids that activates both innate and adaptive immune responses to activate the immune system within the bladder. The plasmid encodes both IL-12 and activators of the innate immune receptor RIG-I. EG-70 is administered intravesically to elicit local stimulation of anti-tumor immune responses providing durable efficacy in high grade non-muscle invasive bladder cancer (NMIBC) while avoidingsystemic toxicities. Methods: In the Phase 1 study(LEGEND; NCT04752722), escalating doses of EG-70 were administered intravesically to patients with BCG-unresponsive Carcinoma in situ (CIS) NMIBC on weeks 1 and 2 or weeks 1, 2, 5, 6 of 12-week treatment cycle. At the week 12 assessment, patients with stable disease (SD) or complete response (CR), as assessed by urine cytology, cystoscopy, and bladder biopsy, were allowed electively to remain on EG-70 for up to 3 additional 12-week cycles. Results: To date, 19 patients have been treated. There have been no DLTs. AEs (48 GR1, 17 GR 2 and 1 GR3) have been largely consistent with urinary tract instrumentation, and were not dose related. Eighteen patients have completed one cycle of EG-70, and 67% have achieved CR. Fifteen patients with CR or SD at the end of cycle 1 elected to receive additional treatment cycles (continuation rate of 15/18 ( 83%)). Durable CRs were seen at all dose levels. Patients who receive additional cycles are followed for durability of response (Table). Complete Response. Conclusions: These results demonstrate the safety, tolerability and durable therapeutic potential of intravesical EG-70 in patients with BCG-unresponsive CIS. A Phase 2 study will proceed in 2023. Clinical trial information: NCT04752722 . [Table: see text]

Endothelial Sash1 Is Required for Lung Maturation through Nitric Oxide Signaling

The sterile alpha motif (SAM) and SRC homology 3 (SH3) domain containing protein 1 (Sash1) acts as a scaffold in TLR4 signaling. We generated Sash1^-/- mice, which die in the perinatal period due to respiratory distress. Constitutive or endothelial-restricted Sash1 loss leads to a delay in maturation of alveolar epithelial cells causing reduced surfactant-associated protein synthesis. We show that Sash1 interacts with β-arrestin 1 downstream of the TLR4 pathway to activate Akt and endothelial nitric oxide synthase (eNOS) in microvascular endothelial cells. Generation of nitric oxide downstream of Sash1 in endothelial cells affects alveolar epithelial cells in a cGMP-dependent manner, inducing maturation of alveolar type 1 and 2 cells. Thus, we identify a critical cell nonautonomous function for Sash1 in embryonic development in which endothelial Sash1 regulates alveolar epithelial cell maturation and promotes pulmonary surfactant production through nitric oxide signaling. Lung immaturity is a major cause of respiratory distress and mortality in preterm infants, and these findings identify the endothelium as a potential target for therapy.

Implication of alpha4 phosphoprotein and the rapamycin-sensitive mammalian target-of-rapamycin pathway in prolactin receptor signalling

A prolactin (PRL)-responsive 3'-end cDNA encoding rat alpha4 phosphoprotein was previously isolated from a rat lymphoma cDNA library. Rat alpha4 is a homologue of yeast Tap42 and is a component of the mammalian target-of-rapamycin (mTOR) signalling pathway that stimulates translation initiation and G1 progression in response to nutrients and growth factors. In the present study, the full-length rat alpha4 cDNA was obtained by 5'-RACE and the 1023 bp open reading frame predicted a 340 amino acid protein of 39.1 kDa. The alpha4 mRNA was expressed in quiescent PRL-dependent Nb2 lymphoma cells deprived of PRL for up to 72 h but expression was downregulated within 4 h of PRL treatment. In contrast, PRL-independent Nb2-Sp cells showed constitutive expression of alpha4 that was not affected by PRL. Western analysis of Nb2 cell lysates or of V5-tagged-alpha4 expressed in COS-1 cells detected a single immunoreactive band of approximately 45 kDa. Enzymatic deglycosylation of affinity-purified 45 kDa alpha4 yielded the predicted 39 kDa protein. Phosphorylation of Nb2 alpha4 was induced by PRL or 2-O-tetradecanoyl-phorbol-13-acetate (TPA) and further enhanced by a combination of PRL and TPA. The Nb2 alpha4 associated with the catalytic subunit of protein phosphatase 2A and localized predominantly in Nb2 nuclear fractions with trace amounts in the cytosol. The immunosuppressant drug rapamycin inhibited proliferation of Nb2 cells in response to PRL or interleukin-2, but had no effect on Nb2-Sp cells. Furthermore, transient overexpression of alpha4 in COS-1 cells inhibited PRL stimulation of the immediate-early gene interferon regulatory factor-1 promoter activity. Therefore, PRL downregulation of alpha4 expression and/or PRL-inducible phosphorylation of alpha4 may be necessary for PRL receptor (PRLr) signalling to the interferon regulatory factor-1 promoter in the Nb2 cells and, furthermore, implicates cross-talk between the mTOR and PRLr signalling cascades during Nb2 cell mitogenesis.