AstraZeneca's (AZN.L) drive to rebuild its portfolio of new medicines received a boost on Tuesday with positive results for a biotech drug for severe asthma that the company has previously flagged as a potential $2 billion-a-year product. The antibody treatment benralizumab, which will compete against rivals including GlaxoSmithKline's (GSK.L) recently launched Nucala, was well tolerated and succeeded in reducing asthma attacks in two pivotal late-stage clinical trials. AstraZeneca said it planned to submit the product for regulatory approval in the United States and Europe in the second half of 2016. Source: Reuters