Evaluating the Use of KIM-1 in Drug Development and Research Following FDA Qualification.

The Biomarker Qualification Program was established at the Center for Drug Evaluation and Research (CDER), Food and Drug Administration (FDA) to expedite the integration of promising biomarkers across multiple drug development programs. The first set of biomarkers qualified in 2008 consisted of seven nonclinical safety biomarkers for the detection of acute drug-induced nephrotoxicity in rats, and included urinary kidney injury molecule-1 (KIM-1). This article discusses the use of KIM-1 in drug development and research before and after CDER's qualification of KIM-1. Use was determined by analyzing relevant documents identified by keyword searches using three databases: 1) an FDA internal database, Document Archiving, Reporting, and Regulatory Tracking System (DARRTS); 2) ClinicalTrials.gov; and 3) PubMed. The results indicate increased use of KIM-1 as a biomarker for detection of kidney injury in drug development programs reviewed by CDER, as well as in research following qualification.

Building a roadmap to biomarker qualification: challenges and opportunities.

The traditional route for regulatory acceptance of biomarkers in drug development is through submission of biomarker data in drug approval submissions in the context of a single drug development program. The US FDA's Critical Path Initiative called for establishment of a biomarker qualification process to enable progress in the drug development paradigm. In response to this, the Center for Drug Evaluation and Research (CDER) established a Biomarker Qualification Program (BQP) to qualify a biomarker for a specific context of use (COU). The qualified biomarker can then be used in multiple drug development programs for this COU without re-review. Here, we describe some of the features of the BQP and two new initiatives that have the potential to aid biomarker development through early interactions with the FDA. Finally, we discuss some of the feedback the FDA has received from submitters and the BQP's actions to strengthen the program.

Extracellular annexins and dynamin are important for sequential steps in myoblast fusion.

Myoblast fusion into multinucleated myotubes is a crucial step in skeletal muscle development and regeneration. Here, we accumulated murine myoblasts at the ready-to-fuse stage by blocking formation of early fusion intermediates with lysophosphatidylcholine. Lifting the block allowed us to explore a largely synchronized fusion. We found that initial merger of two cell membranes detected as lipid mixing involved extracellular annexins A1 and A5 acting in a functionally redundant manner. Subsequent stages of myoblast fusion depended on dynamin activity, phosphatidylinositol(4,5)bisphosphate content, and cell metabolism. Uncoupling fusion from preceding stages of myogenesis will help in the analysis of the interplay between protein machines that initiate and complete cell unification and in the identification of additional protein players controlling different fusion stages.