Updated Overall Survival Analysis From IMpower110: Atezolizumab Versus Platinum-Based Chemotherapy in Treatment-Naive Programmed Death-Ligand 1-Selected NSCLC.

INTRODUCTION: IMpower110 previously revealed significant overall survival (OS) benefit with atezolizumab versus chemotherapy in patients with treatment-naive EGFR- and ALK-negative (wild type [WT]) metastatic NSCLC with high programmed death-ligand 1 (PD-L1) expression (≥50% on tumor cells [TCs] or ≥10% on tumor-infiltrating immune cells [ICs], per SP142 immunohistochemistry assay; p = 0.0106). We present primary OS analyses in lower PD-L1 expression groups and an updated, exploratory analysis in the high PD-L1 expression group. METHODS: This open-label, phase 3 trial randomized patients with PD-L1 expression on greater than or equal to 1% of TC or IC to receive atezolizumab or platinum-based chemotherapy. The primary end point was OS, hierarchically tested in PD-L1 expression WT subgroups: first the high PD-L1 expression subgroup, then the high-or-intermediate PD-L1 expression subgroup (≥5% on TC or IC), and then the any PD-L1 expression subgroup (≥1% on TC or IC). RESULTS: The any PD-L1 expression WT population included 554 patients (excluded 18 EGFR- or ALK-positive patients). With 17 months' additional follow-up, OS improvement in the atezolizumab versus chemotherapy arm was not statistically significant in high-or-intermediate PD-L1 expression WT patients (n = 328; hazard ratio = 0.87, 95% confidence interval: 0.66-1.14, p = 0.3091; median = 19.9 versus 16.1 mo), precluding formal OS testing in any PD-L1 expression WT patients. Exploratory analysis in high PD-L1 expression WT patients (n = 205) revealed maintained OS benefit in the atezolizumab arm (hazard ratio = 0.76, 95% confidence interval: 0.54-1.09; median = 20.2 versus 14.7 mo). Updated safety data continued to favor atezolizumab. CONCLUSIONS: Statistical significance for OS was not revealed in the high-or-intermediate expression WT group, and, as a result, OS in the any PD-L1 expression WT group was not formally tested. No new safety signals were found. This updated analysis of IMpower110 supports using atezolizumab in treatment-naive, metastatic WT NSCLC with high PD-L1 expression.

Atezolizumab for First-Line Treatment of PD-L1-Selected Patients with NSCLC.

BACKGROUND: The efficacy and safety of the anti-programmed death ligand 1 (PD-L1) monoclonal antibody atezolizumab, as compared with those of platinum-based chemotherapy, as first-line treatment for patients with metastatic non-small-cell lung cancer (NSCLC) with PD-L1 expression are not known. METHODS: We conducted a randomized, open-label, phase 3 trial involving patients with metastatic nonsquamous or squamous NSCLC who had not previously received chemotherapy and who had PD-L1 expression on at least 1% of tumor cells or at least 1% of tumor-infiltrating immune cells as assessed by the SP142 immunohistochemical assay. Patients were assigned in a 1:1 ratio to receive atezolizumab or chemotherapy. Overall survival (primary end point) was tested hierarchically according to PD-L1 expression status among patients in the intention-to-treat population whose tumors were wild-type with respect to EGFR mutations or ALK translocations. Within the population with EGFR and ALK wild-type tumors, overall survival and progression-free survival were also prospectively assessed in subgroups defined according to findings on two PD-L1 assays as well as by blood-based tumor mutational burden. RESULTS: Overall, 572 patients were enrolled. In the subgroup of patients with EGFR and ALK wild-type tumors who had the highest expression of PD-L1 (205 patients), the median overall survival was longer by 7.1 months in the atezolizumab group than in the chemotherapy group (20.2 months vs. 13.1 months; hazard ratio for death, 0.59; P = 0.01). Among all the patients who could be evaluated for safety, adverse events occurred in 90.2% of the patients in the atezolizumab group and in 94.7% of those in the chemotherapy group; grade 3 or 4 adverse events occurred in 30.1% and 52.5% of the patients in the respective groups. Overall and progression-free survival favored atezolizumab in the subgroups with a high blood-based tumor mutational burden. CONCLUSIONS: Atezolizumab treatment resulted in significantly longer overall survival than platinum-based chemotherapy among patients with NSCLC with high PD-L1 expression, regardless of histologic type. (Funded by F. Hoffmann-La Roche/Genentech; IMpower110 ClinicalTrials.gov number, NCT02409342.).

Lymph node-independent liver metastasis in a model of metastatic colorectal cancer.

Deciphering metastatic routes is critically important as metastasis is a primary cause of cancer mortality. In colorectal cancer (CRC), it is unknown whether liver metastases derive from cancer cells that first colonize intestinal lymph nodes, or whether such metastases can form without prior lymph node involvement. A lack of relevant metastatic CRC models has precluded investigations into metastatic routes. Here we describe a metastatic CRC mouse model and show that liver metastases can manifest without a lymph node metastatic intermediary. Colorectal tumours transplanted onto the colonic mucosa invade and metastasize to specific target organs including the intestinal lymph nodes, liver and lungs. Importantly, this metastatic pattern differs from that observed following caecum implantation, which invariably involves peritoneal carcinomatosis. Anti-angiogenesis inhibits liver metastasis, yet anti-lymphangiogenesis does not impact liver metastasis despite abrogating lymph node metastasis. Our data demonstrate direct hematogenous spread as a dissemination route that contributes to CRC liver malignancy.

Increased glucocerebrosidase (GBA) 2 activity in GBA1 deficient mice brains and in Gaucher leucocytes.

Lysosomal glucocerebrosidase (GBA1) deficiency is causative for Gaucher disease. Not all individuals with GBA1 mutations develop neurological involvement raising the possibility that other factors may provide compensatory protection. One factor may be the activity of the non-lysosomal ß-glucosidase (GBA2) which exhibits catalytic activity towards glucosylceramide and is reported to be highly expressed in brain tissue. Here, we assessed brain GBA2 enzymatic activity in wild type, heterozygote and GBA1 deficient mice. Additionally, we determined activity in leucocytes obtained from 13 patients with Gaucher disease, 10 patients with enzymology consistent with heterozygote status and 19 controls. For wild type animals, GBA2 accounted for over 85 % of total brain GBA activity and was significantly elevated in GBA1 deficient mice when compared to heterozygote and wild types (GBA1 deficient; 92.4 ± 5.6, heterozygote; 71.5 ± 2.4, wild type 76.8 ± 5.1 nmol/h/mg protein). For the patient samples, five Gaucher patients had GBA2 leucocyte activities markedly greater than controls. No difference in GBA2 activity was apparent between the control and carrier groups. Undetectable GBA2 activity was identified in four leucocyte preparations; one in the control group, two in the carrier group and one from the Gaucher disease group. Work is now required to ascertain whether GBA2 activity is a disease modifying factor in Gaucher disease and to identify the mechanism(s) responsible for triggering increased GBA2 activity in GBA1 deficiency states.

Novel method for genotyping hepatitis B virus on the basis of TaqMan real-time PCR.

Chronic infection with hepatitis B virus (HBV) is an important cause of cirrhosis and cancer of the liver. HBV is currently classified into eight genotypes, A to H. Accumulated evidence shows that the genotype influences both the clinical course of infection and the response to treatment. We describe a new method for genotyping based on TaqMan real-time PCR, which identifies all HBV genotypes without post-PCR processing. In this assay, each sample is processed in four multiplex real-time PCRs, each targeting two or three genotype-specific segments of HBV. By analyzing 185 samples representing all genotypes and different proportions of genotype mixtures, we could validate high accuracy of the assay. We conclude that this new assay represents a significant advancement for both diagnostics and clinical research because it is accurate, practical, and based on a technique that is well established in many virological laboratories.

No evidence for activation of the unfolded protein response in neuronopathic models of Gaucher disease.

Gaucher disease (GD), the most common lysosomal storage disorder (LSD), is caused by defects in the activity of the lysosomal enzyme, glucocerebrosidase, resulting in intracellular accumulation of glucosylceramide (GlcCer). Neuronopathic forms, which comprise only a small percent of GD patients, are characterized by neurological impairment and neuronal cell death. Little is known about the pathways leading from GlcCer accumulation to neuronal death or dysfunction but defective calcium homeostasis appears to be one of the pathways involved. Recently, endoplasmic reticulum stress together with activation of the unfolded protein response (UPR) has been suggested to play a key role in cell death in neuronopathic forms of GD, and moreover, the UPR was proposed to be a common mediator of apoptosis in LSDs (Wei et al. (2008) Hum. Mol. Genet. 17, 469-477). We now systematically examine whether the UPR is activated in neuronal forms of GD using a selection of neuronal disease models and a combination of western blotting and semi-quantitative and quantitative real-time polymerase chain reaction. We do not find any changes in either protein or mRNA levels of a number of typical UPR markers including BiP, CHOP, XBP1, Herp and GRP58, in either cultured Gaucher neurons or astrocytes, or in brain regions from mouse models, even at late symptomatic stages. We conclude that the proposition that the UPR is a common mediator for apoptosis in all neurodegenerative LSDs needs to be re-evaluated.

Successful low-risk hematopoietic cell therapy in a mouse model of type 1 Gaucher disease.

Hematopoietic stem cell-based gene therapy offers the possibility of permanent correction for genetic disorders of the hematopoietic system. However, optimization of present protocols is required before gene therapy can be safely applied as general treatment of genetic diseases. In this study we have used a mouse model of type 1 Gaucher disease (GD) to demonstrate the feasibility of a low-risk conditioning regimen instead of standard radiation, which is associated with severe adverse effects. We first wanted to establish what level of engraftment and glucosylceramidase (GCase) activity is required to correct the pathology of the type 1 GD mouse. Our results demonstrate that a median wild-type (WT) cell engraftment of 7%, corresponding to GCase activity levels above 10 nmoles/hour and mg protein, was sufficient to reverse pathology in bone marrow and spleen in the GD mouse. Moreover, we applied nonmyeloablative doses of busulfan as a pretransplant conditioning regimen and show that even WT cell engraftment in the range of 1%-10% can confer a beneficial therapeutical outcome in this disease model. Taken together, our data provide encouraging evidence for the possibility of developing safe and efficient conditioning protocols for diseases that require only a low level of normal or gene-corrected cells for a permanent and beneficial therapeutic outcome.

Murine models of acute neuronopathic Gaucher disease.

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by mutations in the glucosidase, beta, acid (GBA) gene that encodes the lysosomal enzyme glucosylceramidase (GCase). GCase deficiency leads to characteristic visceral pathology and, in some patients, lethal neurological manifestations. Here, we report the generation of mouse models with the severe neuronopathic form of GD. To circumvent the lethal skin phenotype observed in several of the previous GCase-deficient animals, we genetically engineered a mouse model with strong reduction in GCase activity in all tissues except the skin. These mice exhibit rapid motor dysfunction associated with severe neurodegeneration and apoptotic cell death within the brain, reminiscent of neuronopathic GD. In addition, we have created a second mouse model, in which GCase deficiency is restricted to neural and glial cell progenitors and progeny. These mice develop similar pathology as the first mouse model, but with a delayed onset and slower disease progression, which indicates that GCase deficiency within microglial cells that are of hematopoietic origin is not the primary determinant of the CNS pathology. These findings also demonstrate that normal microglial cells cannot rescue this neurodegenerative disease. These mouse models have significant implications for the development of therapy for patients with neuronopathic GD.

Effective cell and gene therapy in a murine model of Gaucher disease.

Gaucher disease (GD) is a lysosomal storage disorder due to an inherited deficiency in the enzyme glucosylceramidase (GCase) that causes hepatosplenomegaly, cytopenias, and bone disease as key clinical symptoms. Previous mouse models with GCase deficiency have been lethal in the perinatal period or viable without displaying the clinical features of GD. We have generated viable mice with characteristic clinical symptoms of type 1 GD by conditionally deleting GCase exons 9-11 upon postnatal induction. Both transplantation of WT bone marrow (BM) and gene therapy through retroviral transduction of BM from GD mice prevented development of disease and corrected an already established GD phenotype. The gene therapy approach generated considerably higher GCase activity than transplantation of WT BM. Strikingly, both therapeutic modalities normalized glucosylceramide levels and practically no infiltration of Gaucher cells could be observed in BM, spleen, and liver, demonstrating correction at 5-6 months after treatment. The findings demonstrate the feasibility of gene therapy for type 1 GD in vivo. Our type 1 GD mice will serve as an excellent tool in the continued efforts toward development of safe and efficient cell and gene therapy for type 1 GD.