ArQule (ARQL) announced that it had dosed the first patient in the registrational study known as MOSAIC. This study will be tasked with exploring the drug miransertib in treating patients with PIK3CA-related Overgrowth Spectrum disorders (PROS). The move to start the registration study was based on positive data from part A of a phase 1/2 trial. This will be an important study, because if it ends up meeting the endpoint then the biotech will be able to file for regulatory approval of miransertib to treat this patient population. Another solid clinical product in