The day after I applied online I received a call from someone in HR for an (unexpected) informal phone interview. I had another phone interview with someone else from HR and a phone interview with the hiring manager before I was invited to Regeneron for an in-person interview. I was there all day (11am-4pm) and met with 5 other people across various functions (legal, regulatory, med. ed., marketing, etc.). At the end of the interview I was told I would hear from them the following Friday, the next Monday at the latest. After two weeks with no word I followed up twice the woman from HR I interviewed with in person. She said the team had still not made a decision. Finally, three weeks after my in-person interview she called to let me know that they would move forward with another candidate.