PERTH, Australia – In the second multi-billion-dollar pharma merger this week, CSL Ltd. has announced plans to buy Vifor Pharma Ltd. for an equity value of $11.7 billion. It’s also the second largest biopharma merger of 2021, a whisker above Merck & Co Inc.’s $11.5 billion acquisition of Acceleron Pharma Inc. in November, although way off Astrazeneca plc’s $39 billion buy of Alexion Pharmaceuticals Inc. in July.