 Shares of Blueprint Medicines Corp. BPMC, -2.34 gained 3.3 in premarket trading on Thursday after the company announced a deal with investment firm Sixth Street and Royalty Pharma RPRX, -1.10 , which acquires pharmaceutical royalties, worth up to 1.2 billion. Sixth Street will pay 250 million upfront for future royalties for two products, up to 400 million in a senior secured credit facility, and 260 million in a potential credit facility to support any buy-side business opportunities. 