Using Bayesian Dynamic Borrowing to Maximize the Use of Existing Data: A Case-Study

Bayesian Dynamic Borrowing (BDB) designs are being increasingly used in clinical drug development. These methods offer a mathematically rigorous and robust approach to increase efficiency and strengthen evidence by integrating existing trial data into a new clinical trial. The regulatory acceptability of BDB is evolving and varies between and within regulatory agencies. This paper describes how BDB can be used to design a new randomised clinical trial including external data to supplement the planned sample size and discusses key considerations related to data re-use and BDB in drug development programs. A case-study illustrating the planning and evaluation of a BDB approach to support registration of a new medicine with the Center for Drug Evaluation in China will be presented. Key steps and considerations for the use of BDB will be discussed and evaluated, including how to decide whether it is appropriate to borrow external data, which external data can be re-used, the weight to put on the external data and how to decide if the new study has successfully demonstrated treatment benefit.

A Canine Surgical Model of Stroke by Minimally Invasive Occlusion of the Proximal Middle Cerebral Artery

In this study, a model of ischemic stroke by surgical proximal middle cerebral artery (MCA) occlusion was developed on 10 beagle dogs. The advantages of this model are the transtemporal approach and a minimally invasive surgical procedure. Dogs were randomly assigned to two groups: sham-operated (proximal MCA exposure without occlusion) and experimental (permanent proximal MCA occlusion) groups. Different evaluation methods were used to assess the consequences of MCA occlusion in dogs, including neurobehavioral tests, MRI, and immunohistochemical staining. Clear signs of cerebral infarction associated with the region supplied by MCA were confirmed and the model showed good repeatability and consistency. The model can serve as an appropriate large animal model to improve the translation of stroke therapeutics research from the laboratory to the clinical practice.

Suppression of haematopoiesis by sera from patients with aplastic anemia

To describe the suppressive effect of sera from patients with aplastic anemia (AA) on heamatopoietic progenitor cells and explore further the features of serum inhibitor, we first examined the inhibiting activity of the serum on the colony formation of burst-forming units of erythrocyte (BFU-E) and colony-forming units of granulocyte/macrophage (CFU-GM). The potent inhibiting activity was demonstrated in six of 20 patients. Five of the six patients were severe AA (SAA). The suppressive effect did not change after elimination of monocyles and lymphocytes from target MNC. The haematopoietic inhibitory activity of sera from three of the six patients was almost totally neutralized by the MoAb against gamma-IFN. All these three patients were SAA. These data suggest that inhibitor of haematopoietic progenitor cells is present in most of SAA patients. In some patients, the inhibitor was gamma-IFN, which play an important role in the pathogenesis of SAA.