Phase 1B, randomized, double-blind, dose-escalation trial of CPG 10101 in patients with chronic hepatitis C virus.

UNLABELLED: CPG 10101, a synthetic oligodeoxynucleotide (ODN), is a toll-like receptor 9 (TLR9) agonist with antiviral and immunomodulatory properties that could potentially influence chronic infection with HCV. In this multicenter Phase 1b trial, 60 HCV-positive patients (50 genotype 1 HCV) were randomized and received either placebo or CPG 10101 at 0.25, 1, 4, 10, or 20 mg subcutaneously (SC) twice weekly for 4 weeks or at 0.5 or 0.75 mg/kg SC once weekly for 4 weeks. Dose-dependent cytokine induction was observed after administration of CPG 10101. At 24 hours after administering the highest dose of 0.75 mg/kg CPG 10101, interferon (IFN)-gamma-inducible protein 10 (IP-10) had a mean increase over baseline levels (+/-SD) of 15,057 (+/-9769) pg/ml (P < 0.01, compared to placebo); IFN-alpha had a 106 (+/-63.3) pg/ml increase (P < 0.01); and 2'5'-oligoadenylate synthetase (OAS) had a 163 (+/-120.6) pmol/dl increase (P < 0.01). Decreases in HCV RNA also were dose-dependent, with the greatest group geometric mean maximum reduction of 1.69 +/- 0.618 log(10) (P < 0.05) observed in the 0.75 mg/kg dose group. Decreases >/=1 log(10) were seen in 22 of 40 patients who received >/=1 mg CPG 10101, with 3 patients exceeding a 2.5-log(10) reduction. CPG 10101 was well tolerated, and adverse events were consistent with CPG 10101's mechanism of action. CONCLUSION: In this Phase 1 study, CPG 10101 was associated with dose-dependent increases in markers of immune activation and decreases in HCV RNA levels. The data support further clinical studies of CPG 10101 for treating chronic HCV infection.

Immunostimulatory effects of three classes of CpG oligodeoxynucleotides on PBMC from HCV chronic carriers.

BACKGROUND: Chronic hepatitis C virus (HCV) infection results from weak or absent T cell responses. Pegylated-interferon-alpha (IFN-alpha) and ribavirin, the standard of care for chronic HCV, have numerous immune effects but are not potent T cell activators. A potent immune activator such as TLR9 agonist CpG oligodeoxynucleotide (CpG) may complement current treatment approaches. METHODS: Peripheral blood mononuclear cells (PBMC) obtained from HCV chronic carriers who failed previous treatment and from healthy donors were incubated in vitro with the three main CpG classes (A, B or C), recombinant IFN-alpha-2b (IntronA) and/or ribavirin. Proliferation and cytokine secretion (IFN-alpha, IL-10 and IP-10) were evaluated. RESULTS: CpG induced proliferation and cytokine secretion in patterns expected for each CpG class with similar group means for HCV and healthy donors. IntronA and ribavirin, alone or together, had no detectable effects. IntronA and C-Class CpG together induced more IFN-alpha than CpG alone in most subjects. IFN-alpha secretion was proportional to the number of plasmacytoid dendritic cells in PBMC from healthy donors but not HCV donors in whom responses were highly heterogeneous. CONCLUSION: The strong immune stimulatory effect of CpG on PBMC isolated from treatment-failed HCV patients suggests possible utility alone or in combination with current HCV antiviral treatment.

Safety, pharmacokinetics and immune effects in normal volunteers of CPG 10101 (ACTILON), an investigational synthetic toll-like receptor 9 agonist.

UNLABELLED: CPG 10101 (ACTILON) is a novel potent and selective unmethylated cytidine-phosphate-guanosine (CpG)-containing oligodeoxynucleotide agonist of Toll-like receptor 9 (TLR9) being developed for the treatment of chronic infections such as HCV. OBJECTIVES AND METHODS: In this randomized, double-blind, placebo-controlled Phase I study in 48 normal volunteers, we investigated the safety, pharmacokinetic parameters and immune effects of subcutaneous administration of CPG 10101. Five sequential escalating doses from 0.25 to 20 mg were administered twice, 14 days apart. In addition, a 4 mg dose was administered twice weekly for four weeks. RESULTS: A maximum tolerated dose was not reached and the adverse event profile was consistent with the known immunostimulatory effects of TLR9 agonists, mostly consisting of injection site reactions or flu-like symptoms that were generally mild in intensity. CPG 10101 induced interferons, cytokines and chemokines in a pattern consistent with the biology of TLR9. The most sensitive marker was IP-10/CXCL10, whose induction was detected in some subjects even at the 0.25 mg dose. Some cytokines showed transient circulating levels, while the levels of others such as the antiviral cytokine 2',5'-oligoadenylate synthetase were sustained for several days. CONCLUSION: This study warrants further investigation of CPG 10101 for the treatment of chronic infections such as HCV.

Induction of systemic TH1-like innate immunity in normal volunteers following subcutaneous but not intravenous administration of CPG 7909, a synthetic B-class CpG oligodeoxynucleotide TLR9 agonist.

Subcutaneous injection of normal human volunteers with a B-class CpG oligodeoxynucleotide (ODN) TLR9 agonist, CPG 7909, induced a TH1-like pattern of systemic innate immune activation manifested by expression of IL-6, IL-12p40, IFN-alpha, and IFN-inducible chemokines. Serum IP-10 was found to be the most sensitive assay for subcutaneous CPG 7909 stimulation; its level was significantly increased in all subjects at all dose levels, including the lowest tested dose of just 0.0025 mg/kg. This pattern of chemokine and cytokine induction was markedly different from that previously reported to be induced by TLR9 stimulation in rodents, most likely reflecting species-specific differences in the cell types expressing TLR9. Subcutaneous CPG 7909 injection induced transient shifts in blood neutrophils, lymphocytes, and monocytes, consistent with the increased chemokine expression. Levels of acute phase reactants such as C-reactive protein were also increased. A second subcutaneous CPG 7909 injection administered 2 weeks after the first elicited similar immune responses, showing little or no tolerance to the effects of repeated in vivo TLR9 stimulation. Subjects developed dose-dependent transient injection site reactions and flu-like symptoms but otherwise tolerated injection well, with no evidence of organ toxicity or systemic autoimmunity. The activation of innate immunity was dependent on the route of ODN administration, since intravenous injection caused no such effects. These studies indicate that in vivo activation of TLR9 by subcutaneous administration of CPG 7909 could be a well-tolerated immunotherapeutic approach for induction of TH1 innate immune activation.