 Shares of Nektar Therapeutics Inc. NKTR, -34.98 were down 35.9 in trading on Monday after the company announced Friday that it halted development of bempegaldesleukin in combination with Bristol Myers Squibbs BMY, -1.20 Opdivo. The combination was being tested in several types of cancer, including renal cell carcinoma and urothelial carcinoma. 