NephroGenex, a clinical-stage biotech developing treatments for kidney disease, filed on Monday with the SEC to raise up to $47 million in an initial public offering. The Research Triangle Park, NC-based company, which was founded in 2004, plans to list on the NASDAQ under the symbol NRX. NephroGenex initially filed confidentially on November 8, 2013. Aegis Capital is the sole bookrunner on the deal. No pricing terms were disclosed.