Efficacy of pegylated interferon alfa-2b «Algeron» in the treatment of chronic hepatitis C

Aim of the study. To compare efficacy and safety of Algeron 1.5 and 2.0 μg/kg with PegIntron in combination with ribavirin in the treatment of chronic hepatitis C and to determine therapeutic dose of Algeron.Materials and Methods. 150 adult treatment-naive patients with HCV (all genotypes)were randomized into 3 groups. In the two main groups the patients received Algeron in the dosage of 1.5 or 2.0 μg/kg/week, in the active control group – PegIntron 1.5 μg/kg/week in combination with ribavirin. Primary efficacy endpoints were rapid and early virologic response (RVR and EVR).Results. Comparative analysis of virologic response rate after 4th and 12th weeks of the therapy and biochemical response did not show any statistically significant differences between the groups. RVR was observed in 64% and 56% of patients receiving Algeron 1.5 and 2.0 μg/kg, respectively, in the PegIntron group – in 66% (mITTanalysis, p>0,05).The frequency of EVR in Algeron groups after 12 weeks of treatment (regardless of a dose – 1.5 or 2.0 μg/kg) was 94%, in the reference group (PegIntron) – 88% (p>0,05). RVR and EVR rate analysis according to HCV genotype also did not showed statistically significant differences between the groups. Safety profiles of Algeron and PegIntron were similar. The complex assessment of the efficacy and safety allowed to make the conclusion about the optimal therapeutic dose of Algeron, equal to 1.5 μg/kg/week.Conclusions. Results of the study provide evidence of the high efficacy and safety of Algeron for suppression of HCV replication and make it possible to recommend Algeron 1.5 μg/kg weekly in combination with ribavirin for the treatment of chronic hepatitis C in treatment-naÏve patients for 24–48 weeks depending on the HCV genotype

Ранний вирусологический ответ при использовании препарата цепэгинтерферона альфа-2b в комбинации с рибавирином в терапии хронического гепатита С

Algeron (cepeginterferon alfa-2b) is a new pegylated form of interferon alfa containing linear polyethylene glycol (molecular weight 20 kDa). Pharmacokinetic profile of Algeron allows once weekly administration. In phase II–III study 150 treatment-naive patients with compensated liver function were randomized into 3 groups: Algeron 1,5 μg/kg/week, Algeron 2,0 μg/kg/week, and a reference group of PegIntron 1.5 μg/kg/week in combination with ribavirin 800– 1400 mg/day. Comparative ITT -analysis of early virologic response (EVR) showed absence of differences between groups in frequency of EVR. In Algeron groups (regardless of a dose – 1,5 or 2,0 μg/kg) EVR was observed in 94%, in PegIntron group – – in 88% of patients. Complete EVR (HCV RNA≤15 I I U/mL) was recorded in 88% and 84% of patients receiving Algeron 1,5 and 2,0 μg/kg, respectively, in the reference group – – in 84% of patients. There were no statistically significant differences between groups where patients received Algeron in different doses and the reference group, with or without genotype stratification. Adverse events occurring during the treatment with Algeron are dose-dependent; however, their frequency is no more than in patients receiving standard doses of PegIntron. Based on the absence of differences in efficacy and more favorable safety profile of a lower dose of the study drug, the therapeutic dose of Algeron was selected to be 1,5 μg/kg/week.Альгерон (цепэгинтерферон альфа 2b) – инновационный препарат пегилированного интерферона-альфа, содержащий линейную ююмолекулу полиэтиленгликоля молекулярной массой 20 кДа. Фармакокинетический профиль Альгерона позволяет вводить препарат 1 раз в неделю. В рамках клинического исследования фазы 150 ранее не применявших препаратов интерферона пациентов с хроническим гепатитом С были рандомизированы в 3 группы терапии: Альгерон 1,5 мкг/кг/нед, Альгерон 2,0 мкг/кг/нед и группу сравнения – ПегИнтрон 1,5 мкг/кг/нед в комбинации с рибавирином 800– 1400 мг/сут. Сравнительный анализ продемонстрировал отсутствие различий в достижении раннего вирусологического ответа (РВО) между группами. В группах пациентов, получавших Альгерон (независимо от вводимой дозы – 1,5 или 2,0 мкг/кг), РВО наблюдался в 94% случаев, в группе ПегИнтрона – в 88% случаев. Полный РВО (HCV РНК ≤15 МЕ/мл) зарегистрирован у 88% и 84% пациентов, получавших Альгерон в дозах 1,5 и 2,0 мкг/кг соответственно, в группе сравнения – у 84% участников. Анализ частоты наличия РВО, в том числе в зависимости от генотипа вируса гепатита С, не выявил статистически значимых отличий между группами. Нежелательные явления, наблюдавшиеся в процессе лечения Альгероном, были дозозависимыми, однако их частота не превышала таковую при использовании стандартных доз ПегИнтрона. На основании отсутствия различий в эффективности при более благоприятном профиле безопасности низкой дозы исследуемого препарата была выбрана терапевтическая доза Альгерона, равная 1,5 мкг/кг/нед

Some safety aspects of a new russian pegylated interferon-A medication “ALGERON” (phase 1 clinical trial)

Treatment of hepatitis C is one of the most acute international healthcare problems. High standard in management of patients with HCV virus is combined therapy with pegylated interferon-a plus ribavirin. A necessity to develop new medications and to improve current treatment regiments is determined by high social and economic significance of this disease. Safety and tolerance assessment in healthy volunteers, definition of maximum tolerated dose are conducted in first phase clinical trial of original, Russian medication - pegylated interferon-a, named Algeron (INN - Cepeginterferon alfa-2b). Step by step dose escalation of Algeron in groups of several healthy volunteers was applied in this trial. Results of this trial demonstrated, that safety profile of Algeron has no significant differences with safety profiles of analogical pegylated interferon-a medications. Thus Algeron can be recommended for the second phase clinical trials

Structural and functional significance of the FGL sequence of the periplasmic chaperone Caf1M of Yersinia pestis.

The periplasmic molecular chaperone Caf1M of Yersinia pestis is a typical representative of a subfamily of specific chaperones involved in assembly of surface adhesins with a very simple structure. One characteristic feature of this Caf1M-like subfamily is possession of an extended, variable sequence (termed FGL) between the F1 and subunit binding G1 β-strands. In contrast, FGS subfamily members, characterized by PapD, have a short F1-G1 loop and are involved in assembly of complex pili. To elucidate the structural and functional significance of the FGL sequence, a mutant Caf1M molecule (dCaf1M), in which the 27 amino acid residues between the F1 and G1 β-strands had been deleted, was constructed. Expression of the mutated caf1M in Escherichia coli resulted in accumulation of high levels of dCaf1M. The far-UV circular dichroism spectra of the mutant and wild-type proteins were indistinguishable and exhibited practically the same temperature and pH dependencies. Thus, the FGL sequence of Caf1M clearly does not contribute significantly to the stability of the protein conformation. Preferential cleavage of Caf1M by trypsin at Lys-119 confirmed surface exposure of this part of the FGL sequence in the isolated chaperone and periplasmic chaperone-subunit complex. There was no evidence of surface-localized Caf1 subunit in the presence of the Caf1A outer membrane protein and dCaf1M. In contrast to Caf1M, dCaf1M was not able to form a stable complex with Caf1 nor could it protect the subunit from proteolytic degradation in vivo. This demonstration that the FGL sequence is required for stable chaperone-subunit interaction, but not for folding of a stable chaperone, provides a sound basis for future detailed molecular analyses of the FGL subfamily of chaperones

Influence of the conserved disulphide bond, exposed to the putative binding pocket, on the structure and function of the immunoglobulin-like molecular chaperone Caf1M of Yersinia pestis.

The Yersinia pestis protein Caf1M is a typical representative of a subfamily of periplasmic molecular chaperones with characteristic structural and functional features, one of which is the location of two conserved cysteine residues close to the putative binding pocket. We show that these residues form a disulphide bond, the reduction and alkylation of which significantly increases the dissociation constant of the Caf1M-Caf1 (where Caf 1 is a polypeptide subunit of the capsule) complex [from a Kd of (4.77+/-0.50)x10(-9) M for the intact protein to one of (3.68+/-0.68)x10(-8) M for the modified protein]. The importance of the disulphide bond for the formation of functional Caf1M in vivo was demonstrated using an Escherichia coli dsbA mutant carrying the Y. pestis f1 operon. In accordance with the CD and fluorescence measurements, the disulphide bond is not important for maintenance of the overall structure of the Caf1M molecule, but would appear to affect the fine structural properties of the subunit binding site. A three-dimensional model of the Caf1M-Caf1 complex was designed based on the published crystal structure of PapD (a chaperone required for Pap pili assembly) complexed with a peptide corresponding to the C-terminus of the papG subunit. In the model the disulphide bond is in close proximity to the invariant Caf1M Arg-23 and Lys-142 residues that are assumed to anchor the C-terminal group of the subunit. The importance of this characteristic disulphide bond for the orchestration of the binding site and subunit binding, as well as for the folding of the protein in vivo, is likely to be a common feature of this subfamily of Caf1M-like chaperones. A possible model for the role of the disulphide bond in Caf1 assembly is discussed