A demonstration of analytical similarity comparing a proposed biosimilar pegfilgrastim and reference pegfilgrastim.

BACKGROUND: Recombinant human granulocyte-colony stimulating factor (G-CSF, filgrastim) is used primarily to reduce incidence and duration of severe neutropenia and its associated complications in cancer patients that have received a chemotherapy regimen. The pegylated form of filgrastim, "pegfilgrastim", is a long-acting form that requires only a once-per-cycle administration for the management of chemotherapy-induced neutropenia. Apobiologix, a division of ApoPharma USA, Inc., and Intas Pharmaceuticals Limited have co-developed a proposed pegfilgrastim biosimilar to US-licensed pegfilgrastim. METHODS: The analytical similarity of Apobiologix pegfilgrastim and US-licensed pegfilgrastim with respect to their physicochemical profile was established using a wide range of rigorous orthogonal analytical techniques. Biological function was compared using receptor binding analyses, in vitro proliferation assays, and in vivo hematopoietic progenitor mobilization. RESULTS: Apobiologix pegfilgrastim and the US-licensed pegfilgrastim reference product were found to be highly similar analytically with respect to molecular mass, primary, secondary and tertiary protein structures, purity, charge, and hydrophobicity. No differences in receptor binding affinity were observed, and all samples demonstrated similar in vitro and in vivo bioactivity. CONCLUSION: These studies provide robust evidence supporting the structural and functional similarity between Apobiologix pegfilgrastim and the US-licensed reference pegfilgrastim, and hence their biosimilarity.

Modulation of γ-secretase by EVP-0015962 reduces amyloid deposition and behavioral deficits in Tg2576 mice.

BACKGROUND: A hallmark of Alzheimer's disease is the presence of senile plaques in human brain primarily containing the amyloid peptides Aß42 and Aß40. Many drug discovery efforts have focused on decreasing the production of Aß42 through γ-secretase inhibition. However, identification of γ-secretase inhibitors has also uncovered mechanism-based side effects. One approach to circumvent these side effects has been modulation of γ-secretase to shift Aß production to favor shorter, less amyloidogenic peptides than Aß42, without affecting the overall cleavage efficiency of the enzyme. This approach, frequently called γ-secretase modulation, appears more promising and has lead to the development of new therapeutic candidates for disease modification in Alzheimer's disease. RESULTS: Here we describe EVP-0015962, a novel small molecule γ-secretase modulator. EVP-0015962 decreased Aß42 in H4 cells (IC50 = 67 nM) and increased the shorter Aß38 by 1.7 fold at the IC50 for lowering of Aß42. AßTotal, as well as other carboxyl-terminal fragments of amyloid precursor protein, were not changed. EVP-0015962 did not cause the accumulation of other γ-secretase substrates, such as the Notch and ephrin A4 receptors, whereas a γ-secretase inhibitor reduced processing of both. A single oral dose of EVP-0015962 (30 mg/kg) decreased Aß42 and did not alter AßTotal peptide levels in a dose-dependent manner in Tg2576 mouse brain at an age when overt Aß deposition was not present. In Tg2576 mice, chronic treatment with EVP-0015962 (20 or 60 mg/kg/day in a food formulation) reduced Aß aggregates, amyloid plaques, inflammatory markers, and cognitive deficits. CONCLUSIONS: EVP-0015962 is orally bioavailable, detected in brain, and a potent, selective γ-secretase modulator in vitro and in vivo. Chronic treatment with EVP-0015962 was well tolerated in mice and lowered the production of Aß42, attenuated memory deficits, and reduced Aß plaque formation and inflammation in Tg2576 transgenic animals. In summary, these data suggest that γ-secretase modulation with EVP-0015962 represents a viable therapeutic alternative for disease modification in Alzheimer's disease.

Abnormal cognition, sleep, EEG and brain metabolism in a novel knock-in Alzheimer mouse, PLB1.

Late-stage neuropathological hallmarks of Alzheimer's disease (AD) are ß-amyloid (ßA) and hyperphosphorylated tau peptides, aggregated into plaques and tangles, respectively. Corresponding phenotypes have been mimicked in existing transgenic mice, however, the translational value of aggressive over-expression has recently been questioned. As controlled gene expression may offer animal models with better predictive validity, we set out to design a transgenic mouse model that circumvents complications arising from pronuclear injection and massive over-expression, by targeted insertion of human mutated amyloid and tau transgenes, under the forebrain- and neurone-specific CaMKIIα promoter, termed PLB1(Double). Crossing with an existing presenilin 1 line resulted in PLB1(Triple) mice. PLB1(Triple) mice presented with stable gene expression and age-related pathology of intra-neuronal amyloid and hyperphosphorylated tau in hippocampus and cortex from 6 months onwards. At this early stage, pre-clinical (18)FDG PET/CT imaging revealed cortical hypometabolism with increased metabolic activity in basal forebrain and ventral midbrain. Quantitative EEG analyses yielded heightened delta power during wakefulness and REM sleep, and time in wakefulness was already reliably enhanced at 6 months of age. These anomalies were paralleled by impairments in long-term and short-term hippocampal plasticity and preceded cognitive deficits in recognition memory, spatial learning, and sleep fragmentation all emerging at ∼12 months. These data suggest that prodromal AD phenotypes can be successfully modelled in transgenic mice devoid of fibrillary plaque or tangle development. PLB1(Triple) mice progress from a mild (MCI-like) state to a more comprehensive AD-relevant phenotype, which are accessible using translational tools such as wireless EEG and microPET/CT.

Pathological Hallmarks, Clinical Parallels, and Value for Drug Testing in Alzheimer's Disease of the APP[V717I] London Transgenic Mouse Model.

The APP[V717I] London (APP-Ld) mouse model recapitulates important pathological and clinical hallmarks of Alzheimer's disease (AD) and is therefore a valuable paradigm for evaluating therapeutic candidates. Historically, both the parenchymal and vascular amyloid deposits, and more recently, truncated and pyroglutamate-modified Abeta(3(pE)-42) species, are perceived as important hallmarks of AD-pathology. Late stage symptoms are preceded by robust deficits in orientation and memory that correlate in time with Abeta oligomerization and GSK3ß-mediated phosphorylation of endogenous murine Tau, all markers that have gained considerable interest during the last decade. Clinical parallels with AD patients and the value of the APP-Ld transgenic mouse model for preclinical in vivo testing of candidate drugs are discussed.

Amyloid inhibitors enhance survival of cultured human islets.

BACKGROUND: Amyloid fibrils created by misfolding and aggregation of proteins are a major pathological feature in a variety of degenerative diseases. Therapeutic approaches including amyloid vaccines and anti-aggregation compounds in models of amyloidosis point to an important role for amyloid in disease pathogenesis. Amyloid deposits derived from the beta-cell peptide islet amyloid polypeptide (IAPP or amylin) are a characteristic of type 2 diabetes and may contribute to loss of beta-cells in this disease. METHODS: We developed a cellular model of rapid amyloid deposition using cultured human islets and observed a correlation between fibril accumulation and beta-cell death. A series of overlapping peptides derived from IAPP was generated. RESULTS: A potent inhibitor (ANFLVH) of human IAPP aggregation was identified. This inhibitory peptide prevented IAPP fibril formation in vitro and in human islet cultures leading to a striking increase in islet cell viability. CONCLUSIONS: These findings indicate an important contribution of IAPP aggregation to beta-cell death in situ and point to therapeutic applications for inhibitors of IAPP aggregation in enhancing beta-cell survival. GENERAL SIGNIFICANCE: Anti-amyloid compounds could potentially reduce the loss of beta-cell mass in type 2 diabetes and maintain healthy human islet cultures for beta-cell replacement therapies.

Targeted delivery of ribavirin improves outcome of murine viral fulminant hepatitis via enhanced anti-viral activity.

Side effects of interferon-ribavirin combination therapy limit the sustained viral response achievable in hepatitis C virus (HCV) patients. Coupling ribavirin to macromolecular carriers that target the drug to the liver would reduce systemic complications. The aim of this study was to evaluate the efficacy of a hemoglobin-ribavirin conjugate (HRC 203) in murine hepatitis virus strain 3 (MHV-3) induced viral hepatitis. HRC 203 had greater anti-viral activity on both isolated hepatocytes and macrophages, whereas both ribavirin and HRC 203 inhibited production of the pro-inflammatory cytokines interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) by macrophages. In vivo, untreated MHV-3-infected mice all developed clinical and biochemical signs of acute viral hepatitis and died by day 4 post infection. Livers recovered from untreated infected mice showed greater than 90% necrosis. In contrast, survival was enhanced in both ribavirin- and HRC 203-treated mice with a marked reduction in biochemical [ALT(max) 964 +/- 128 IU/L (ribavirin); 848 +/- 212 IU/L (HRC 203)] and histological evidence of hepatic necrosis (<10% in ribavirin/HRC 203 vs. 90% in untreated controls). Clinically, HRC 203-treated mice behaved normally, in contrast to ribavirin-treated mice, which developed lethargy and abnormal fur texture. In conclusion, targeted delivery of ribavirin to the liver alters the course of MHV-3 infection as demonstrated by prolonged survival, improved behavior, and reduced signs of histologically evident disease, as well as inhibition of viral replication and production of inflammatory cytokines in vitro.

Identification of minimal peptide sequences in the (8-20) domain of human islet amyloid polypeptide involved in fibrillogenesis.

We have examined a series of overlapping peptide fragments from the 8-20 region of human islet amyloid polypeptide (IAPP) with the objective of defining the smallest fibril-forming domain. Peptide fragments corresponding to LANFLV (residues 12-17) and FLVHSS (residues 15-20) were strong enhancers of beta-sheet transition and fibril formation. Negative stain electron microscopy illustrated the ability of these peptide fragments to form fibrils independently when incubated alone in solution. Circular dichroism analysis revealed that when full-length human IAPP was incubated in the presence of these two fragments, fibrillogenesis was accelerated. While the two fragments, LANFLV and FLVHSS, were able to enhance the recruitment of additional IAPP molecules during fibril formation, the "seeding" activity of these peptides had no effect on altering IAPP-induced cytotoxcity as determined by cell culture studies. Therefore, this study has identified two internal IAPP peptide fragments within the 8-20 domain that may have a role in enhancing the folding and aggregation of human IAPP. These fragments are the smallest sequences identified, within the 8-20 region of hIAPP, that can independently form fibrils, and that can interact with IAPP to assemble into fibrils with characteristics similar as those formed by human IAPP alone.

Design of peptide-based inhibitors of human islet amyloid polypeptide fibrillogenesis.

Human islet amyloid polypeptide (IAPP) is the major component of amyloid deposits found in the pancreas of over 90% of all cases of type-2 diabetes. We have generated a series of overlapping hexapeptides to target an amyloidogenic region of IAPP (residues 20-29) and examined their effects on fibril assembly. Peptide fragments corresponding to SNNFGA (residues 20-25) and GAILSST (residues 24-29) were strong inhibitors of the beta-sheet transition and amyloid aggregation. Circular dichroism indicated that even at 1:1 molar ratios, these peptides maintained full-length IAPP (1-37) in a largely random coil conformation. Negative stain electron microscopy revealed that co-incubation of these peptides with IAPP resulted in the formation of only semi-fibrous aggregates and loss of the typical high density and morphology of IAPP fibrils. This inhibitory activity, particularly for the SNNFGA sequence, also correlated with a reduction in IAPP-induced cytotoxicity as determined by cell culture studies. In contrast, the peptide NFGAIL (residues 22-27) enhanced IAPP fibril formation. Conversion to the amyloidogenic beta-sheet was immediate and the accompanying fibrils were more dense and complex than IAPP alone. The remaining peptide fragments either had no detectable effects or were only weakly inhibitory. Specificity of peptide activity was illustrated by the fragments, SSNNFG and AILSST. These differed from the most active inhibitors by only a single amino acid residue but delayed the random-to-beta conformational change only when used at higher molar ratios. This study has identified internal IAPP peptide fragments which can regulate fibrillogenesis and may be of therapeutic use for the treatment of type-2 diabetes.