By Reuters Staff 1 Min Read FILE PHOTO: The Merck logo is seen at a gate to the Merck & Co campus in Linden, New Jersey, U.S., July 12, 2018. REUTERS/Brendan McDermid (Reuters) - Merck & Co Inc said on Thursday it would buy drug developer Pandion Therapeutics Inc for about $1.85 billion in cash, to expand its portfolio of drugs that target autoimmune diseases. The $60-per-share deal represents about 134% premium to Pandion’s closing price on Wednesday. Pandion’s lead drug candidate, PT101, last month met its main goals of safety and tolerability in an early-stage trial in patients with autoimmune diseases. The transaction is expected to close in the first half of 2021, the companies said in a joint statement.