Shares of Seattle Genetics /zigman2/quotes/203326163/composite SGEN +1.16% rallied 9.3% in premarket trading on Monday after it announced two cancer deals with Merck & Co. Inc. /zigman2/quotes/209956077/composite MRK +0.55% . Shares of Merck were up 0.6%. The first deal allows Merck to co-develop and commercialize ladiratuzumab vedotin, which is in mid-stage studies, and potentially in combination with Keytruda, Merck's blockbuster cancer therapy. As part of this deal, Merck will pay $600 million upfront, with milestone payments up to $2.6 billion. Merck will also take a $1 billion equity investment in the company. As part of the second deal, Merck will exclusively license cancer therapy Tukysa in Asia, the Middle East and Latin America, for $125 million upfront, with up to $65 million in additional milestone payments. Seattle's stock has gained 31.2% so far this year, while shares of Merck are down 7.8%. The S&P 500 /zigman2/quotes/210599714/realtime SPX -0.02% has gained 3.4% year-to-date.