Michael Pehl has resigned as CEO of Immunomedics (NASDAQ: [[ticker:IMMU]]), 15 months after he left Celgene (NASDAQ: [[ticker:CELG]]) to take the top job at the Morris Plains, NJ, company. In a press release, Immunomedics says Pehl is returning to Europe. According to a securities filing, Pehl will remain an Immunomedics employee for 30 days to help with the transition of his responsibilities. The announcement comes a month after the FDA rejected Immunomedics triple negative breast cancer drug sacituzumab govitecan due to manufacturing problems.