Royalty Pharma today announced a preliminary offer to purchase Elan (NYSE:ELN) for $11 per share in a deal being valued at $6.6 billion.

The pharmaceutical investment company had first contacted Elan on Feb. 18. The two companies met two days later, but Elan had not offered a decision. In today's news release, Royalty expressed surprise that Elan last week outlined future business plans without mentioning the offer.

Elan issued its own release today, calling Royalty's timing "highly opportunistic" due to Elan's recent restructuring following the sale of its stake in multiple sclerosis drug Tysabri. The company also noted the "heavily conditional nature" of Royalty's offer.

Royalty's statement offered investors a choice between Elan's sale and "[remaining] an investor in a company whose material assets ... following the completion of the Tysabri Transaction, will consist of cash and the Tysabri Royalty while Elan's management pursues its announced strategy which includes maintaining expected operating expenses in the range of US$170-190 million in the 2013 financial year and investing in a variety of yet-to-be-disclosed business assets."

Elan said it has been working for more than a year on "a number of strategic transactions that, should they be consummated, would be to the benefit of our public shareholders. ... Any credible proposal which may be made by Royalty Pharma or any other party will of course be considered by the Company ..."

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.