Regeneron Pharmaceuticals has completed the acquisition of Sanofi's rights to cemiplimab, a collaborative drug under the trade name Libtayo. Cemiplimab is a PD-1 inhibitor for cancer immunotherapy. Regeneron paid $900 million and will pay a royalty of 11% of net sales. In addition, Sanofi will receive $100 million from Regeneron after FDA or EC approval of the drug as a first-line therapy for non-small cell lung cancer in combination with chemotherapy, and up to $100 million more depending on sales volume over the next 2 years.