In May 2020 Regeneron announced it would repurchase around $5 billion of its shares, held directly by Sanofi. Prior to the transaction Sanofi held 23.2 million Regeneron shares. In June, the company announced it had agreed a potential $2 billion deal with Translate Bio, expanding an already existing collaboration for COVID-19 treatments. The company agreed to produce 60 million doses of a coronavirus vaccine for the United Kingdom government in July 2020. It uses recombinant protein-based technology for Sanofi's flu vaccine along with GSK's pandemic technology and was seeking regulatory approval by the first half of 2021. Sanofi also agreed to a $2.1 billion deal with the United States for 100 million doses. In August, Sanofi announced it would acquire Principia Biopharma for $3.7 billion, acquiring its BTK inhibitor programme. The acquisition was completed in September 2020. In November, Sanofi announced it would acquire Kiadis Pharma for €308 million (around $359 million, or €5.45 per share) expanding its immuno-oncology pipeline with the acquisition of Kiadis' three clinical compounds: K-NK002 in Phase II trials for hematopoietic stem cell transplants in blood cancer, K-NK003 for relapsed or refractory acute myeloid leukemia and K-NK-ID101 for COVID-19.