[Non-publication is common among phase 1, single-center, not prospectively registered, or early terminated clinical drug trials]. / Hoeveel klinische geneesmiddelenstudies worden uiteindelijk gepubliceerd?

The objective of this study was to investigate the occurrence and determinants of non-publication of clinical drug trials in the Netherlands. All clinical drug trials reviewed by the 28 Institutional Review Boards (IRBs) in the Netherlands in 2007 were followed-up from approval to publication. Candidate determinants were the sponsor, phase, applicant, centers, therapeutic effect expected, type of trial, approval status of the drug(s), drug type, participant category, oncology or other disease area, prospective registration, and early termination. The main outcome was publication as peer reviewed article. The percentage of trials that were published, crude and adjusted odds ratio (OR), and 95% confidence interval (CI) were used to quantify the associations between determinants and publication. In 2007, 622 clinical drug trials were reviewed by IRBs in the Netherlands. By the end of follow-up, 19 of these were rejected by the IRB, another 19 never started inclusion, and 10 were still running. Of the 574 trials remaining in the analysis, 334 (58%) were published as peer-reviewed article. The multivariable logistic regression model identified the following determinants with a robust, statistically significant association with publication: phase 2 (60% published; adjusted OR 2.6, 95% CI 1.1-5.9), phase 3 (73% published; adjusted OR 4.1, 95% CI 1.7-10.0), and trials not belonging to phase 1-4 (60% published; adjusted OR 3.2, 95% CI 1.5 to 6.5) compared to phase 1 trials (35% published); trials with a company or investigator as applicant (63% published) compared to trials with a Contract Research Organization (CRO) as applicant (50% published; adjusted OR 1.7; 95% CI 1.1-2.8); and multicenter trials also conducted in other EU countries (68% published; adjusted OR 2.2, 95% CI 1.1-4.4) or also outside the European Union (72% published; adjusted OR 2.0, 95% CI 1.0-4.0) compared to single-center trials (45% published). Trials that were not prospectively registered (48% published) had a lower likelihood of publication compared to prospectively registered trials (75% published; adjusted OR 0.5, 95% CI 0.3-0.8), as well as trials that were terminated early (33% published) compared to trials that were completed as planned (64% published; adjusted OR 0.2, 95% CI 0.1-0.3). The non-publication rate of clinical trials seems to have improved compared to previous inception cohorts, but is still far from optimal, in particular among phase 1, single-center, not prospectively registered, and early terminated trials.

Collaborative study for the validation of alternative in vitro potency assays for human tetanus immunoglobulins.

An international collaborative study to validate 2 alternative in vitro methods for the potency testing of human tetanus immunoglobulin products was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM). The study, run in the framework of the Biological Standardisation Programme (BSP) under the aegis of the European Commission and the Council of Europe, involved 21 official medicines control and industry laboratories from 15 countries. Both methods, an enzyme-linked immunoassay (EIA) and a toxoid inhibition assay (TIA), showed good reproducibility, repeatability and precision. EIA and TIA discriminated between low, medium and high potency samples. Potency estimates correlated well and both values were in close agreement with those obtained by in vivo methods. Moreover, these alternative methods allowed to resolve discrepant results between laboratories that were due to product potency loss and reporting errors. The study demonstrated that EIA and TIA are suitable quality control methods for tetanus immunoglobulin, which can be standardised in a control laboratory using a quality assurance system. Consequently, the Group of Experts on Human Blood and Blood Products of the European Pharmacopoeia revised the monograph on human tetanus immunoglobulins to include both the methods as compendial alternatives to the in vivo mouse challenge assay.

Collaborative study for the validation of alternative in vitro potency assays for human tetanus immunoglobulin.

The European Pharmacopoeia (Ph. Eur.) monograph Human tetanus immunoglobulin (0398) gives a clear outline of the in vivo assay to be performed to determine the potency of human tetanus immunoglobulins during their development. Furthermore, it states that an in vitro method shall be validated for the batch potency estimation. Since no further guidance is given on the in vitro assay, every control laboratory concerned is free to design and validate an in-house method. At the moment there is no agreed in vitro method available. The aim of this study was to validate and compare 2 alternative in vitro assays, i.e. an enzyme-linked immunoassay (EIA) and a toxoid inhibition assay (TIA), through an international collaborative study, in view of their eventual inclusion into the Ph. Eur.. The study was run in the framework of the Biological Standardisation Programme (BSP), under the aegis of the European Commission and the Council of Europe. The collaborative study reported here involved 21 laboratories (public and industry) from 15 countries. Initially, 3 samples with low, medium and high potencies were tested by EIA and TIA. Results showed good reproducibility and repeatability of the 2 in vitro methods. The correlation of the data with the in vivo potency assigned by the manufacturers however appeared initially poor for high potency samples. Thorough re-examination of the data showed that the in vivo potencies assigned by the manufacturers had to be corrected: one for potency loss at the time of in vitro testing and one because of a reporting error. After these corrections the values obtained by in vivo and in vitro methods were in close agreement. A supplementary collaborative work was carried out to validate the 2 methods for immunoglobulin products with high potencies. Eight laboratories (public and industry) took part in this additional study to test 3 samples with medium and high potencies by EIA and TIA. Results confirmed that the 2 alternative methods are comparable in terms of assay repeatability, precision and reproducibility. In all laboratories, both methods discriminated between the low, medium and high potency samples. Analysis of the data collected in this study showed a good correlation between EIA and TIA potency estimates as well as a close agreement between values obtained by in vitro and in vivo methods. The study demonstrated that EIA and TIA are suitable quality control methods for polyclonal human tetanus immunoglobulin, which can be standardised in a quality control laboratory using a quality assurance system. Consequently, the Ph. Eur. Group of Experts 6B on Human Blood and Blood products decided in April 2009 to include both methods as examples in the Ph. Eur. monograph 0398 on Human Tetanus immunoglobulin.

Phlorizin treatment prevents the decrease in plasma insulin levels but not the progressive histopathological changes in the pancreatic islets during aging of Zucker diabetic fatty rats.

A hallmark of Type 2 diabetes mellitus (T2DM) is chronic hyperglycemia, which is thought to play a role in pancreatic beta-cell failure. Here we investigated whether treatment of Zucker diabetic fatty (ZDF) rats, an animal model for T2DM, with the renal glucose transport inhibitor phlorizin could prevent alterations in the pancreatic islets. ZDF rats were treated with phlorizin or vehicle for 13 weeks starting with 6-week-old rats and before the onset of hyperglycemia. During the treatment, blood glucose levels in sham-treated ZDF rats increased rapidly from 7.7 +/- 0.3 to 24.8 +/- 0.6 mmol/l, whereas those in phlorizin-treated ZDF rats increased only slightly, but significantly, from 7.0 +/- 0.2 to 8.9 +/- 0.6 mmol/l. Phlorizin prevented the decrease in plasma insulin levels and caused a higher increase in body weight of the ZDF rats. Compared to 6-week-old untreated ZDF rats, in 19-week-old sham- and phlorizin-treated ZDF rats similar changes were found in islet architecture (more irregular boundaries and a disrupted mantle of peripheral islet cells) and in the mitochondria at the ultrastructural level (swelling of the matrix and disruption of the cristae). Using reverse transcriptase-polymerase chain reaction, no differences in mRNA expression levels were found for insulin, islet amyloid polypeptide (IAPP), and the prohormone convertase (PC) 1 and PC2 between 6-week-old untreated ZDF rats and 19-week-old sham- and phlorizin-treated ZDF rats. However, immunohistochemistry revealed similar decreases in insulin and IAPP protein expression in 19-week-old sham- and phlorizin-treated ZDF rats compared to those in 6-week-old untreated ZDF rats. These observations indicate that during aging of ZDF rats phlorizin treatment does not prevent the decreases in insulin and IAPP protein expression and the progressive histopathological changes in the pancreatic islets. Therefore, it is highly unlikely that these changes are caused by chronic hyperglycemia.