Two Phase 3 Trials of Gantenerumab in Early Alzheimer's Disease.

BACKGROUND: Monoclonal antibodies that target amyloid-beta (Aß) have the potential to slow cognitive and functional decline in persons with early Alzheimer's disease. Gantenerumab is a subcutaneously administered, fully human, anti-Aß IgG1 monoclonal antibody with highest affinity for aggregated Aß that has been tested for the treatment of Alzheimer's disease. METHODS: We conducted two phase 3 trials (GRADUATE I and II) involving participants 50 to 90 years of age with mild cognitive impairment or mild dementia due to Alzheimer's disease and evidence of amyloid plaques on positron-emission tomography (PET) or cerebrospinal fluid (CSF) testing. Participants were randomly assigned to receive gantenerumab or placebo every 2 weeks. The primary outcome was the change from baseline in the score on the Clinical Dementia Rating scale-Sum of Boxes (CDR-SB; range, 0 to 18, with higher scores indicating greater cognitive impairment) at week 116. RESULTS: A total of 985 and 980 participants were enrolled in the GRADUATE I and II trials, respectively. The baseline CDR-SB score was 3.7 in the GRADUATE I trial and 3.6 in the GRADUATE II trial. The change from baseline in the CDR-SB score at week 116 was 3.35 with gantenerumab and 3.65 with placebo in the GRADUATE I trial (difference, -0.31; 95% confidence interval [CI], -0.66 to 0.05; P = 0.10) and was 2.82 with gantenerumab and 3.01 with placebo in the GRADUATE II trial (difference, -0.19; 95% CI, -0.55 to 0.17; P = 0.30). At week 116, the difference in the amyloid level on PET between the gantenerumab group and the placebo group was -66.44 and -56.46 centiloids in the GRADUATE I and II trials, respectively, and amyloid-negative status was attained in 28.0% and 26.8% of the participants receiving gantenerumab in the two trials. Across both trials, participants receiving gantenerumab had lower CSF levels of phosphorylated tau 181 and higher levels of Aß42 than those receiving placebo; the accumulation of aggregated tau on PET was similar in the two groups. Amyloid-related imaging abnormalities with edema (ARIA-E) occurred in 24.9% of the participants receiving gantenerumab, and symptomatic ARIA-E occurred in 5.0%. CONCLUSIONS: Among persons with early Alzheimer's disease, the use of gantenerumab led to a lower amyloid plaque burden than placebo at 116 weeks but was not associated with slower clinical decline. (Funded by F. Hoffmann-La Roche; GRADUATE I and II ClinicalTrials.gov numbers, NCT03444870 and NCT03443973, respectively.).

Gantenerumab reduces amyloid-ß plaques in patients with prodromal to moderate Alzheimer's disease: a PET substudy interim analysis.

BACKGROUND: We previously investigated low doses (105 or 225 mg) of gantenerumab, a fully human monoclonal antibody that binds and removes aggregated amyloid-ß by Fc receptor-mediated phagocytosis, in the SCarlet RoAD (SR) and Marguerite RoAD (MR) phase 3 trials. Several lines of evidence suggested that higher doses may be necessary to achieve clinical efficacy. We therefore designed a positron emission tomography (PET) substudy to evaluate the effect of gantenerumab uptitrated to 1200 mg every 4 weeks on amyloid-ß plaques as measured using florbetapir PET in patients with prodromal to moderate Alzheimer's disease (AD). METHODS: A subset of patients enrolled in the SR and MR studies who subsequently entered the open-label extensions (OLEs) were included in this substudy. Patients were aged 50 to 90 years with a clinical diagnosis of probable prodromal to moderate AD and were included based on a visual read of the original screening scan in the double-blind phase. Patients were assigned to 1 of 5 titration schedules (ranging from 2 to 10 months) with a target gantenerumab dose of 1200 mg every 4 weeks. The main endpoint of this substudy was change in amyloid-ß plaque burden from OLE baseline to week 52 and week 104, assessed using florbetapir PET. Florbetapir global cortical signal was calculated using a prespecified standard uptake value ratio method converted to the Centiloid scale. RESULTS: Sixty-seven of the 89 patients initially enrolled had ≥ 1 follow-up scan by August 15, 2018. Mean amyloid levels were reduced by 39 Centiloids by the first year and 59 Centiloids by year 2, a 3.5-times greater reduction than was seen after 2 years at 225 mg in SR. At years 1 and 2, 37% and 51% of patients, respectively, had amyloid-ß plaque levels below the amyloid-ß positivity threshold. CONCLUSION: Results from this exploratory interim analysis of the PET substudy suggest that gantenerumab doses up to 1200 mg resulted in robust amyloid-ß plaque removal at 2 years. PET amyloid levels were consistent with sparse-to-no neuritic amyloid-ß plaques in 51% of patients after 2 years of therapy. Amyloid reductions were similar to those observed in other placebo-controlled studies that have suggested potential clinical benefit. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01224106 (SCarlet RoAD) and NCT02051608 (Marguerite RoAD).

Expression of Prostacyclin-Synthase in Human Breast Cancer: Negative Prognostic Factor and Protection against Cell Death In Vitro.

Endogenously formed prostacyclin (PGI2) and synthetic PGI2 analogues have recently been shown to regulate cell survival in various cell lines. To elucidate the significance of PGI2 in human breast cancer, we performed immunohistochemistry to analyze expression of prostacyclin-synthase (PGIS) in 248 human breast cancer specimens obtained from surgical pathology files. We examined patients' 10-year survival retrospectively by sending a questionnaire to their general practitioners and performed univariate analysis to determine whether PGIS expression correlated with patient survival. Lastly, the effects of PGI2 and its analogues on cell death were examined in a human breast cancer cell line (MCF-7) and a human T-cell leukemia cell line (CCRF-CEM). PGIS expression was observed in tumor cells in 48.7% of samples and was associated with a statistically significant reduction in 10-year survival (P = 0.038; n = 193). Transient transfection of PGIS into MCF-7 cells exposed to sulindac increased cell viability by 50% and exposure to carbaprostacyclin protected against sulindac sulfone induced apoptosis in CCRF-CEM cells. Expression of PGIS is correlated with a reduced patient survival and protects against cell death in vitro, suggesting that PGIS is a potential therapeutic target in breast cancer.

PKC theta cooperates with PKC alpha in alloimmune responses of T cells in vivo.

The physiological roles of PKC alpha and PKC theta were defined in T cell immune functions downstream of the antigen receptor. To investigate the hypothesis that both PKC isotypes may have overlapping functions, we generated mice lacking both genes. We find that PKC alpha(-/-)/theta(-/-) animals have additive T cell response defects in comparison to animals carrying single mutations in these genes. Our studies demonstrate that the activities of PKC alpha and PKC theta converge to regulate both IL-2 cytokine responses and T cell intrinsic alloreactivity in vivo. Mechanistically, this PKC alpha/theta crosstalk primarily affects the NFAT transactivation pathway in T lymphocytes, as observed by decreased phosphorylation of Ser-9 on GSK3 beta, reduced nuclear translocation and DNA binding of NFAT in isolated PKC alpha(-/-)/theta(-/-) CD3(+) T cells. This additive defect proved to be of physiological relevance, because PKC alpha(-/-)/theta(-/-) mice demonstrated significantly prolonged allograft survival in heart transplantation experiments, whereas both PKC alpha(-/-) and PKC theta(-/-) mice showed only minimal graft prolongation when compared to wild type controls. While PKC theta appears to be the rate-limiting PKC isotype mediating T lymphocyte activation, we here provide genetic evidence that PKC alpha and PKC theta have overlapping functions in alloimmunoreactivity in vivo and both PKC theta and PKC alpha isotypes must be targeted to prevent organ allograft rejection.

Characterization of eltenac and novel COX-2 selective thiopheneacetic acid analogues in vitro and in vivo.

We assessed the effect of novel selective thiopheneacetic acids on cyclooxygenase isoenzymes in vitro and in vivo. Thiopheneacetic acid Eltenac and derivatives were investigated in this study. In human whole blood experiments these derivatives were potent inhibitors of COX-2 (IC(50)=0.02-0.4 microM) with less pronounced effect on COX-1 (IC(50)=0.15-5.6 microM). With COX-1/COX-2 ratios between 7.5- and 16-fold they are in the range of Celecoxib (13-fold). The parent drug Eltenac demonstrated no selectivity for COX-2. In a rat paw edema model, these compounds showed reduction of edema volume in the range of 36-45% at 10 mg/kg (Eltenac 52%, Diclofenac 51%). However, the compounds were superior to Diclofenac and Eltenac with respect to their ulcerogenic and gastrointestinal properties. Introduction of a nitrate-ester moiety to either Eltenac or a derivative did neither improve selectivity or potency in vitro, nor ulcerogenicity in vivo. Molecular modeling of selective thiopheneacetic acid derivatives to the active site of human COX-2 suggested similar binding properties as Lumiracoxib and Diclofenac. In summary, modification of Eltenac generates moderately selective COX-2 drugs in the range of Celecoxib with respect to potency and selectivity. The drugs showed potent anti-inflammatory properties and significant improvement of animal survival in a sub-chronical experimental set up. Thiopheneacetic derivatives are characterized by low pK(a) values, short microsomal half-lives and binding mode to COX-2 similar to Diclofenac and Lumiracoxib. These properties may also have an impact on the transient inhibition of COX-2-dependent prostacyclin, thereby being less associated with vascular complications.

G3139 and other CpG-containing immunostimulatory phosphorothioate oligodeoxynucleotides are potent suppressors of the growth of human tumor xenografts in nude mice.

Several phosphorothioate antisense oligodeoxynucleotides (ODN) are developed to target factors potentially involved in tumor growth and apoptosis suppression. Among them, the 18-mer G3139 (Oblimersen), which targets Bcl-2, is currently being tested in phase II and phase III clinical trials for various tumors in combination with chemotherapy. On the other hand, ODNs containing CpG dinucleotides (CpG-ODN) within specific-sequence contexts (CpG motifs) have been shown to activate rodent or primate immune cells via toll-like receptor 9 (TLR9) and have demonstrated remarkable T cell-dependent antitumor efficacy in a series of murine tumor models. However, immune cell activation by CpG-ODN is largely diminished upon C-5 methylation at CpG cytosine. As G3139 contains CpG motifs, we questioned whether the antitumor effects seen in human tumor xenografts might be abrogated by cytosine C-5 methylation of G3139, which retained the ability of G3139 to suppress Bcl-2 expression in tissue culture, or by similar derivatization of other phosphorothioate ODNs developed for the immune activation of rodent or human cells. The in vivo antitumor efficacy of the immunostimulatory H1826 and H2006 ODNs was compared with that of G3139. Bcl-2 suppression achieved by G3139 purportedly sensitizes tumor cells toward cytotoxic agents, and some of the experiments employed combinations of ODN with such drugs as cisplatin or etoposide. H1826, H2006, and G3139 all produced similar, striking, growth inhibitory effects on either H69 SCLC, A2780 ovarian carcinoma, or A549 lung adenocarcinoma human tumor xenografts at doses of 0.3 mg/kg and 1 mg/kg (H1826, H2006) or 12 mg/kg (G3139) per day. In contrast, the H2006-mC (1 mg/kg) or G3139-mC (12 mg/kg) derivatives demonstrated no significant antitumor effects. The combination of G3139 (12 mg/kg) with cisplatin produced some additive antitumor efficacy, which was not seen in combinations of G3139-mC (12 mg/kg) or H1826 (1 mg/kg) with cisplatin. G3139, at a dose of 12 mg/kg, alone induced extensive enlargement of the spleen. Immunostimulation was evaluated in vitro by flow cytometric measurements of the CD80 and CD86 activation markers found on CD19+ murine splenocytes. The CpG-ODN producing strong antitumor effects in vivo also induced these activation markers in vitro, in contrast to the in vivo inactive G3139-mC. Our data indicate a significant contribution of the immunostimulatory properties of CpG-ODN (including G3139) to the antitumor effects observed in nude mouse xenograft models. This is in contrast to previous data presented by other authors indicating that the activity of G3139 in human tumor xenografts was Bcl-2 specific. Furthermore, as nude mice are devoid of T cells, a T cell-mediated immune response apparently is not required for the potent antitumor responses observed here; innate immune responses are sufficient.