Protocol Design Variables Highly Correlated with, and Predictive of, Clinical Trial Performance.

Tufts Center for the Study of Drug Development (Tufts CSDD) collected data on trial design elements and clinical trial performance outcomes from 187 protocols provided by 20 companies. 10 design variables were tested for correlations with 11 performance variables, and regression models of each performance variable were tested. Results: Many significant correlations were found (p < .01, p < .05). The number of countries and the number of sites were each positively correlated with amendment frequency, longer screening and study duration as well as study participant dropout rates. The number of internal reviews prior to protocol finalization was also positively correlated with these same performance outcomes. In regression modeling, scientific and operational design characteristics were significant predictors of cycle time, enrollment and retention outcomes, and amendment frequency, even when controlling for phase and therapeutic area. These predictors included the number of endpoints, eligibility criteria, procedures per visit, number of countries, and investigative sites. The results of this analysis suggest practical considerations for optimizing protocol performance.

The Impact of Protocol Amendments on Clinical Trial Performance and Cost.

BACKGROUND: Tufts Center for the Study of Drug Development (Tufts CSDD), in collaboration with 15 pharmaceutical companies and contract research organizations, gathered data on substantial global protocol amendments to better understand how to manage and to reduce the significant unplanned expense and delays associated with major changes to finalized protocol designs. METHODS: Data from 836 phase I-IIB/IV protocols were analyzed to understand amendment prevalence. Impact assessments were based on data from 136 randomly selected amendments. Data from 52 protocols were analyzed to derive estimates of the direct cost to implement amendments. RESULTS: Tufts CSDD found that 57% of protocols had at least one substantial amendment, and nearly half (45%) of these amendments were deemed "avoidable." Phase II and III protocols had a mean number of 2.2 and 2.3 global amendments, respectively. Protocols with one or more global amendments tended to be larger in scope, with longer patient recruitment durations and overall study durations compared with those without a global amendment. Protocols with at least one substantial amendment had fewer actual screened and enrolled patients relative to the original baseline plan than did those protocols without an amendment. The median direct cost to implement a substantial amendment was US$141,000 for a phase II protocol and $535,000 for a phase III protocol. CONCLUSIONS: The study findings provide insights into optimizing development planning, protocol design, and clinical trial management practices.

Cerebrospinal fluid beta-amyloid and dynabridging in Alzheimer's disease drug development.

Cerebrospinal fluid (CSF) has become a matrix for biomarker discovery and development in recent years. A number of biomarkers for pathogenic processes in Alzheimer's disease have been identified. Studies have revealed the diagnostic potential of CSF amyloid-beta, tau and phosphorylated tau levels. California Clinical Trials has conducted a number of studies in collaboration with drug developers that demonstrate the importance of CSF amyloid-beta peptides as biomarkers for drug development. These studies also establish the utility of CSF sampling via continuous indwelling lumbar catheterization (dynabridging) for assessing pharmacokinetic and pharmacodynamic parameters in conjunction with biomarker analysis. Corroborative approaches using multiple biomarker methods including neuroimaging and CSF biomarkers will provide a complete picture of the Alzheimer's disease brain.

Effect of an oral iron(III)-hydroxide polymaltose complex on tetracycline pharmacokinetics in patients with iron deficiency anemia.

The study was carried out as an open-label, but laboratory-blind, single-dose, single-centre, randomized, two-period crossover study. Twenty-two patients with iron deficiency anemia completed the study. The study consisted of two treatment phases of 36 h, separated by a washout period of between 6 and 14 days. The two treatments were given orally. The reference treatment was tetracycline (CAS 60-54-8) alone (2 x 250 mg capsules) and the test treatment was iron(III)-hydroxide polymaltose complex (IPC, Maltofer) together with tetracycline (2 x 250 mg capsules). IPC had no pharmacokinetic effect on the rate of absorption of tetracycline. With concomitant administration of tetracycline and IPC sufficiently high tetracycline concentrations, to ensure bacteriostasis, will be reached. An inhibitor effect of IPC to the tetracycline absorption, as it is known for ferrous salts, could not be observed.