But during the back-and-forth, some unexpected tax scrutiny almost derailed the talks, according to a new proxy filing. Beginning in late 2019, Alexion management came under pressure from investors, most notably proxy fighter Elliott Advisers, to put itself on the block. Even though the drugmaker set its not-for-sale record straight that December, the buzz continued as "several stockholders encouraged the company to explore strategic alternatives," Alexion said in a securities filing. Pascal Soriot took the hint.