Dive Brief: Amgen on Monday said it has submitted for Food and Drug Administration approval its asthma drug hopeful tezepelumab, advancing a medicine that's crucially important to its plans for growing beyond the aging blockbusters that have sustained its business for years. Tezepelumab, which Amgen has developed with partner AstraZeneca for nearly a decade, is a biologic drug that works to reduce airway inflammation in a new way. By blocking a protein known as TSLP, tezepelumab is thought to prevent the release of other, pro-inflammatory proteins, thereby reducing asthma attacks. Results from a study called NAVIGATOR, released in November, bore this hypothesis out, showing treatment with the drug reduced attacks in patients with severe asthma. But data from a much smaller clinical trial just one month later raised some questions about how competitive tezepelumab might be.