Recent studies have identified somatic
mutations in patients with metastatic breast cancer and found some of them to promote estrogen-independent activation of the receptor. The degree to which all ...recurrent mutants can drive estrogen-independent activities and reduced sensitivity to ER antagonists like fulvestrant is not established. In this report, we characterize the spectrum of
mutations from more than 900 patients.
mutations were detected in 10%, with D538G being the most frequent (36%), followed by Y537S (14%). Several novel, activating mutations were also detected (e.g., L469V, V422del, and Y537D). Although many mutations lead to constitutive activity and reduced sensitivity to ER antagonists, only select mutants such as Y537S caused a magnitude of change associated with fulvestrant resistance
Correspondingly, tumors driven by Y537S, but not D5358G, E380Q, or S463P, were less effectively inhibited by fulvestrant than more potent and bioavailable antagonists, including AZD9496. These data point to a need for antagonists with optimal pharmacokinetic properties to realize clinical efficacy against certain
mutants.
A diversity of activating
mutations exist, only some of which confer resistance to existing ER antagonists that might be overcome by next-generation inhibitors such as AZD9496.
.
Lipid nanoparticles have demonstrated utility in hepatic delivery of a range of therapeutic modalities and typically deliver their cargo via low-density lipoprotein receptor-mediated endocytosis. For ...patients lacking sufficient low-density lipoprotein receptor activity, such as those with homozygous familial hypercholesterolemia, an alternate strategy is needed. Here we show the use of structure-guided rational design in a series of mouse and non-human primate studies to optimize a GalNAc-Lipid nanoparticle that allows for low-density lipoprotein receptor independent delivery. In low-density lipoprotein receptor-deficient non-human primates administered a CRISPR base editing therapy targeting the ANGPTL3 gene, the introduction of an optimized GalNAc-based asialoglycoprotein receptor ligand to the nanoparticle surface increased liver editing from 5% to 61% with minimal editing in nontargeted tissues. Similar editing was noted in wild-type monkeys, with durable blood ANGPTL3 protein reduction up to 89% six months post dosing. These results suggest that GalNAc-Lipid nanoparticles may effectively deliver to both patients with intact low-density lipoprotein receptor activity as well as those afflicted by homozygous familial hypercholesterolemia.
The incidence of early seizures (occurring within 7 days of stroke onset) after intracerebral haemorrhage reaches 30% when subclinical seizures are diagnosed by continuous EEG. Early seizures might ...be associated with haematoma expansion and worse neurological outcomes. Current guidelines do not recommend prophylactic antiseizure treatment in this setting. We aimed to assess whether prophylactic levetiracetam would reduce the risk of acute seizures in patients with intracerebral haemorrhage.
The double-blind, randomised, placebo-controlled, phase 3 PEACH trial was conducted at three stroke units in France. Patients (aged 18 years or older) who presented with a non-traumatic intracerebral haemorrhage within 24 h after onset were randomly assigned (1:1) to levetiracetam (intravenous 500 mg every 12 h) or matching placebo. Randomisation was done with a web-based system and stratified by centre and National Institutes of Health Stroke Scale (NIHSS) score at baseline. Treatment was continued for 6 weeks. Continuous EEG was started within 24 h after inclusion and recorded over 48 h. The primary endpoint was the occurrence of at least one clinical seizure within 72 h of inclusion or at least one electrographic seizure recorded on continuous EEG, analysed in the modified intention-to-treat population, which comprised all patients who were randomly assigned to treatment and who had a continuous EEG performed. This trial was registered at ClinicalTrials.gov, NCT02631759, and is now closed. Recruitment was prematurely stopped after 48% of the recruitment target was reached due to a low recruitment rate and cessation of funding.
Between June 1, 2017, and April 14, 2020, 50 patients with mild-to-moderate severity intracerebral haemorrhage were included: 24 were assigned to levetiracetam and 26 to placebo. During the first 72 h, a clinical or electrographic seizure was observed in three (16%) of 19 patients in the levetiracetam group versus ten (43%) of 23 patients in the placebo group (odds ratio 0·16, 95% CI 0·03–0·94, p=0·043). All seizures in the first 72 h were electrographic seizures only. No difference in depression or anxiety reporting was observed between the groups at 1 month or 3 months. Depression was recorded in three (13%) patients who received levetiracetam versus four (15%) patients who received placebo, and anxiety was reported for two (8%) patients versus one (4%) patient. The most common treatment-emergent adverse events in the levetiracetam group versus the placebo group were headache (nine 39% vs six 24%), pain (three 13% vs ten 40%), and falls (seven 30% vs four 16%). The most frequent serious adverse events were neurological deterioration due to the intracerebral haemorrhage (one 4% vs four 16%) and severe pneumonia (two 9% vs two 8%). No treatment-related death was reported in either group.
Levetiracetam might be effective in preventing acute seizures in intracerebral haemorrhage. Larger studies are needed to determine whether seizure prophylaxis improves functional outcome in patients with intracerebral haemorrhage.
French Ministry of Health.
Hepatitis E virus (HEV) can induce chronic infections in the case of immunosuppression, which are sometimes not cured with ribavirin. Furthermore, sofosbuvir is a highly potent inhibitor of HCV ...polymerase and was shown to inhibit HEV genotype-3 replication in vitro. We report here the outcome of sofosbuvir/ribavirin therapy on a chronic HEV infection in a heart transplant recipient non-responder to ribavirin. After 24 weeks, the regimen failed to cure the persistent HEV infection, highlighting the need of therapeutic options for HEV-infected immunosuppressed patients.
The tumor microenvironment is emerging as a key regulator of cancer growth and progression, however the exact mechanisms of interaction with the tumor are poorly understood. Whilst the majority of ...genomic profiling efforts thus far have focused on the tumor, here we investigate RNA-Seq as a hypothesis-free tool to generate independent tumor and stromal biomarkers, and explore tumor-stroma interactions by exploiting the human-murine compartment specificity of patient-derived xenografts (PDX).Across a pan-cancer cohort of 79 PDX models, we determine that mouse stroma can be separated into distinct clusters, each corresponding to a specific stromal cell type. This implies heterogeneous recruitment of mouse stroma to the xenograft independent of tumor type. We then generate cross-species expression networks to recapitulate a known association between tumor epithelial cells and fibroblast activation, and propose a potentially novel relationship between two hypoxia-associated genes, human MIF and mouse Ddx6. Assessment of disease subtype also reveals MMP12 as a putative stromal marker of triple-negative breast cancer. Finally, we establish that our ability to dissect recruited stroma from trans-differentiated tumor cells is crucial to identifying stem-like poor-prognosis signatures in the tumor compartment.In conclusion, RNA-Seq is a powerful, cost-effective solution to global analysis of human tumor and mouse stroma simultaneously, providing new insights into mouse stromal heterogeneity and compartment-specific disease markers that are otherwise overlooked by alternative technologies. The study represents the first comprehensive analysis of its kind across multiple PDX models, and supports adoption of the approach in pre-clinical drug efficacy studies, and compartment-specific biomarker discovery.
VERVE-101 is an investigational in vivo CRISPR base-editing medicine designed to alter a single DNA base in the
gene, permanently turn off hepatic protein production, and thereby durably lower ...low-density lipoprotein cholesterol. We test the efficacy, durability, tolerability, and potential for germline editing of VERVE-101 in studies of nonhuman primates and a murine F1 progeny study.
Cynomolgus monkeys were given a single intravenous infusion of a vehicle control (n=10) or VERVE-101 at a dose of 0.75 mg/kg (n=4) or 1.5 mg/kg (n=22) with subsequent follow-up up to 476 days. Two studies assessed the potential for germline editing, including sequencing sperm samples from sexually mature male nonhuman primates treated with VERVE-101 and genotyping offspring from female mice treated with the murine surrogate of VERVE-101 (VERVE-101mu).
Liver biopsies 14 days after dosing noted mean
editing of 46% and 70% in monkeys treated with VERVE-101 at 0.75 and 1.5 mg/kg, respectively. This translated into mean reductions in blood PCSK9 (proprotein convertase subtilisin/kexin type 9) of 67% and 83% and reductions of low-density lipoprotein cholesterol of 49% and 69% at the 0.75 and 1.5 mg/kg doses, respectively, assessed as time-weighted average change from baseline between day 28 and up to 476 days after dosing. Liver safety monitoring noted a transient rise in alanine aminotransferase and aspartate aminotransferase concentrations after infusion that fully resolved by day 14 with no accompanying change in total bilirubin. In a subset of monkeys necropsied 1 year after dosing, no findings related to VERVE-101 were identified on macroscopic and histopathologic assessment of the liver and other organs. In the study to assess potential germline editing of male nonhuman primates, sperm samples collected after VERVE-101 dosing showed no evidence of
editing. Among 436 offspring of female mice treated with a saturating dose of VERVE-101mu, the
edit was transmitted in 0 of 436 animals.
VERVE-101 was well tolerated in nonhuman primates and led to 83% lower blood PCSK9 protein and 69% lower low-density lipoprotein cholesterol with durable effects up to 476 days after dosing. These results have supported the initiation of a first-in-human clinical trial in patients with heterozygous familial hypercholesterolemia and atherosclerotic cardiovascular disease.
Gene-editing technologies, which include the CRISPR-Cas nucleases
and CRISPR base editors
, have the potential to permanently modify disease-causing genes in patients
. The demonstration of durable ...editing in target organs of nonhuman primates is a key step before in vivo administration of gene editors to patients in clinical trials. Here we demonstrate that CRISPR base editors that are delivered in vivo using lipid nanoparticles can efficiently and precisely modify disease-related genes in living cynomolgus monkeys (Macaca fascicularis). We observed a near-complete knockdown of PCSK9 in the liver after a single infusion of lipid nanoparticles, with concomitant reductions in blood levels of PCSK9 and low-density lipoprotein cholesterol of approximately 90% and about 60%, respectively; all of these changes remained stable for at least 8 months after a single-dose treatment. In addition to supporting a 'once-and-done' approach to the reduction of low-density lipoprotein cholesterol and the treatment of atherosclerotic cardiovascular disease (the leading cause of death worldwide
), our results provide a proof-of-concept for how CRISPR base editors can be productively applied to make precise single-nucleotide changes in therapeutic target genes in the liver, and potentially in other organs.
Acquired resistance to PI3K/mTOR/Akt pathway inhibitors is often associated with compensatory feedback loops involving the activation of oncogenes. Here, we have generated everolimus resistance in ...ER+ breast cancer cells and in long-term estrogen deprived (LTED) models that mimic progression on anti-estrogens. This allowed us to uncover MYC as a driver of mTOR inhibitor resistance. We demonstrate that both everolimus resistance and acute treatment of everolimus can lead to the upregulation of MYC mRNA, protein expression and, consequently, the enrichment of MYC signatures as revealed by RNA sequencing data. Depletion of MYC resulted in resensitization to everolimus, confirming its functional importance in this setting. Furthermore, ChIP assays demonstrate that MYC upregulation in the everolimus resistant lines is mediated by increased association of the BRD4 transcription factor with the MYC gene. Finally, JQ1, a BRD4 inhibitor combined with everolimus exhibited increased tumor growth inhibition in 3D Matrigel models and an in vivo xenograft model. These data suggest that MYC plays an important role in mediating resistance to everolimus in ER+ and ER+/LTED models. Furthermore, given the regulation ofMYCby BRD4 in this setting, these data have implications for increased therapeutic potential of combining epigenetic agents with mTOR inhibitors to effectively downregulate otherwise difficult to target transcription factors such as MYC.
Although endocrine therapy is successfully used to treat patients with estrogen receptor (ER) positive breast cancer, a substantial proportion of this population will relapse. Several mechanisms of ...acquired resistance have been described including activation of the mTOR pathway, increased activity of CDK4 and activating mutations in ER. Using a patient derived xenograft model harboring a common activating ER ligand binding domain mutation (D538G), we evaluated several combinatorial strategies using the selective estrogen receptor degrader (SERD) fulvestrant in combination with chromatin modifying agents, and CDK4/6 and mTOR inhibitors. In this model, fulvestrant binds WT and MT ER, reduces ER protein levels, and downregulated ER target gene expression. Addition of JQ1 or vorinostat to fulvestrant resulted in tumor regression (41% and 22% regression, respectively) though no efficacy was seen when either agent was given alone. Interestingly, although the CDK4/6 inhibitor palbociclib and mTOR inhibitor everolimus were efficacious as monotherapies, long-term delayed tumor growth was only observed when co-administered with fulvestrant. This observation was consistent with a greater inhibition of compensatory signaling when palbociclib and everolimus were co-dosed with fulvestrant. The addition of fulvestrant to JQ1, vorinostat, everolimus and palbociclib also significantly reduced lung metastatic burden as compared to monotherapy. The combination potential of fulvestrant with palbociclib or everolimus were confirmed in an MCF7 CRISPR model harboring the Y537S ER activating mutation. Taken together, these data suggest that fulvestrant may have an important role in the treatment of ER positive breast cancer with acquired ER mutations.
PDF
