A phase III randomized, multicentre, double blind, active controlled trial to compare the efficacy and safety of two different anagrelide formulations in patients with essential thrombocythaemia - the TEAM-ET 2·0 trial.

Anagrelide is an established treatment option for essential thrombocythaemia (ET). A prolonged release formulation was developed with the aim of reducing dosing frequency and improving tolerability, without diminishing efficacy. This multicentre, randomized, double blind, active-controlled, non-inferiority trial investigated the efficacy, safety and tolerability of anagrelide prolonged release (A-PR) over a reference product in high-risk ET patients, either anagrelide-naïve or -experienced. In a 6 to 12-week titration period the individual dose for the consecutive 4-week maintenance period was identified. The primary endpoint was the mean platelet count during the maintenance period (3 consecutive measurements, day 0, 14, 28). Of 112 included patients 106 were randomized. The mean screening platelet counts were 822 × 109 /l (95% confidence interval (CI) 707-936 × 109 /l) and 797 × 109 /l (95% CI 708-883 × 109 /l) for A-PR and the reference product, respectively. Both treatments effectively reduced platelet counts, to mean 281 × 109 /l for A-PR (95% CI 254-311) and 305 × 109 /l (95% CI 276-337) for the reference product (P < 0·0001, for non-inferiority). Safety and tolerability were comparable between both drugs. The novel prolonged-release formulation was equally effective and well tolerated compared to the reference product. A-PR provides a more convenient dosing schedule and will offer an alternative to licensed immediate-release anagrelide formulations.

Analysis of the human cytomegalovirus pp65-directed T-cell response in healthy HLA-A2-positive individuals.

Human cytomegalovirus (HCMV) is contained by T-lymphocyte responses focused towards the major tegument protein pp65. To systematically identify T-cell epitopes, we applied the following strategy: 441 overlapping 15mer peptides spanning the entire HCMV pp65 antigen in 1-aa steps were screened in enzyme-linked immunospot (ELispot) assays for interferon gamma (IFN-gamma) secretion by peripheral blood mononuclear cells (PBMCs) from nine healthy HCMV-seropositive subjects expressing human leukocyte antigen (HLA)-A2. This analysis confirmed a number of previously known epitopes and revealed several new ones. A total of 26 epitopes were identified, including 14 HLA-A2, four HLA-B7, -B35, -812 and -B44 restricted class I epitopes, six class II epitopes, and two epitopes of unknown restriction. Three novel HLA-A2 epitopes were confirmed using T2-cells, and one peptide for which only binding data had been published so far was verified. Two novel class II epitopes were confirmed by intracellular cytokine staining. Responses were usually oligoclonal against up to seven HLA-A2 epitopes, albeit with a few dominating epitopes. Clusters of overlapping epitopes (hot-spots) were identified. These and the newly identified T-cell epitopes may be of great value for epitope-based immunotherapeutic approaches, including peptide vaccines.

Therapeutic vaccination of chronic hepatitis C nonresponder patients with the peptide vaccine IC41.

BACKGROUND & AIMS: IC41 is a synthetic peptide vaccine containing 7 relevant hepatitis C virus (HCV) T-cell epitopes and the T helper cell (Th)1/Tc1 adjuvant poly-L-arginine. IC41 has been shown to be safe and to induce HCV-specific interferon (IFN)-gamma-secreting CD4+ and CD8+ T cells in healthy volunteers. We aimed to investigate whether IC41 is able to induce HCV-specific T-cell responses also in chronic hepatitis C patients. METHODS: Sixty HLA-A2-positive chronic HCV patients not responding to or relapsing from standard therapy were randomized in a double-blind phase II study into 5 groups to receive 6 vaccinations of IC41 (3 different dose groups), HCV peptides alone, or poly-L-arginine alone. RESULTS: IC41 was well tolerated, and no drug-related serious adverse events or induction of hepatitis were observed. T-cell proliferation was recorded in up to 67% of patients in the 3 IC41 vaccine groups but only in 17% of patients treated with peptides alone. IFN-gamma enzyme-linked immunospot assay responses were observed exclusively in the IC41 groups with response rates up to 42%. There were 3 RNA responders with transient >1-log declines of HCV serum RNA associated with the strongest IFN-gamma enzyme-linked immunospot assay values within all 60 patients. CONCLUSIONS: This study showed that the HCV peptide vaccine IC41 can induce HCV-specific Th1/Tc1 responses in a subset of difficult to treat HCV nonresponder patients despite persisting viremia. However, changes in HCV RNA occurred only in single patients. Because strongest T-cell responses were associated with HCV RNA decline, further studies with optimized vaccine regimens and combination therapies have been initiated.

Functional and phenotypic characterization of peptide-vaccine-induced HCV-specific CD8+ T cells in healthy individuals and chronic hepatitis C patients.

Only very limited information on phenotype and function of vaccine-induced CD8+ T cells is available for humans. We investigated hepatitis C virus-specific CD8+ T cells after vaccination with the HCV peptide-vaccine IC41 which includes 5 MHC-class I and 3 MHC class-II-restricted epitopes. In healthy subjects, IC41 induced both HCV-specific central memory as well as effector CD8+ T cells which rapidly expanded upon antigen exposure in vitro. IFNgamma production was dependent on formulation of the synthetic peptides with the adjuvant poly-l-arginine. In chronic HCV patients, the frequency of HCV-specific CD8+ T cells increased after vaccination with a decline of CD45RA-positive effector memory cells in some but not all patients. Thus, this study suggests that HCV-specific memory cells can be induced by peptide vaccination and that a reversion of functional impaired phenotypes by therapeutic vaccination is possible in chronic HCV infection.

Immunogenicity and safety of a novel therapeutic hepatitis C virus (HCV) peptide vaccine: a randomized, placebo controlled trial for dose optimization in 128 healthy subjects.

As interferon/ribavirin-based standard therapy is curative in only about half of HCV patients, there remains an important need for alternatives including vaccines. The novel peptide vaccine IC41 consists of five synthetic peptides harboring HCV T cell epitopes and poly-L-arginine as synthetic adjuvant. In this randomized, placebo-controlled trial, 128 HLA-A2 positive healthy volunteers received four s.c. vaccinations of seven different doses IC41, HCV peptides alone, poly-l-arginine alone or saline solution, every 4 weeks. IC41 was safe and well tolerated. Mild to moderate local reactions were transient. Immunogenicity was assessed using T cell epitope specific [3H]-thymidine proliferation, IFN-gamma ELIspot and HLA-tetramer assays. IC41 induced responses in all dose groups. Higher responder rates were recorded in higher dose groups and increasing number of vaccinations were associated with higher responder rates and more robust responses. Poly-L-arginine was required for the aimed-for Th1/Tc1-type immunity (IFN-gamma secreting T cells).