While shares of Nektar Therapeutics (NKTR) have performed strongly year-to-date, "significant upside remains," Mizuho analyst Difei Yang tells investors in a research note. A recent Nature article on IL-2 immunotherapy and new players in the field provide support for Nektar's approach to immuno-oncology, says Yang. Further, she believes the company's collaborations with large pharma, including Bristol-Myers Squibb (BMY) and Pfizer, underscore the "strong potential" of NKTR-214. With multiple data readouts expected in 2019, Yang sees "significant value" in Nektar shares. She reiterates a Buy rating on the name with an $81 price target. The stock closed yesterday down 3% to $44.76.