NKTR-214 (investigational agent) is an IL-2 pathway agonist designed to target CD122, a
      protein which is found on certain immune cells (known as CD8+ T Cells and Natural Killer
      Cells) to expand these cells to promote their anti-tumor effects. Nivolumab is a full human
      monoclonal antibody that binds to PD-1 (programmed cell death protein 1) on immune cells and
      promotes anti-tumor effects. NKTR-214, nivolumab and ipilimumab each target the immune system
      differently and may act synergistically to promote anti-cancer effects.

      The study is designed in four parts.

      Part 1: Dose escalation of NKTR-214 in combination with nivolumab. Part 1 has been completed
      and the recommended phase 2 dose (RP2D) has been identified, which is being studied further
      in Parts 2, 3 and 4 of the study.

      Part 2: Dose expansion of NKTR-214 in combination with nivolumab. Patients with the following
      tumor types (Melanoma, RCC, NSCLC, UC, mBC and CRC) will be enrolled to receive the RP2D of
      NKTR-214 in combination with nivolumab. In addition, NKTR-214 with nivolumab and other
      anti-cancer therapies including cytotoxic chemotherapy will be evaluated in select patients
      with NSCLC. Each cohort in Part 2 has a target enrollment of 12-36 patients and could include
      up to a total of 650 patients who are either checkpoint-therapy naïve or anti-PD-1 or
      anti-PD-L1 relapsed/refractory. One dedicated and separate cohort in Part 2 will evaluate
      NKTR-214 with nivolumab in an additional 100 second-line NSCLC patients previously treated
      with an anti-PD-1 or anti-PD-L1 in combination with doublet platinum-containing cytotoxic
      chemotherapy in first-line.

      Part 3: Schedule and safety finding of NKTR-214 in combination with nivolumab and ipilimumab.
      During this part of the study, the RP2D triplet combination schedules will be determined in
      the following tumor types: RCC, NSCLC, Melanoma, or UC.

      Part 4: Dose expansion of triplet combinations of NKTR-214 in combination with nivolumab and
      ipilimumab in select tumor types. Each cohort will enroll between 6-36 patients and could
      include up to 106 patients. Enrollment into Part 4 will commence once the RP2D for the
      triplet combination has been established in Part 3 for each respective tumor type.

      All patients enrolled in the study will be closely monitored for safety, tolerability and
      response per RECIST criteria. The primary efficacy endpoint of the combination will be
      assessed using objective response rate (ORR). Exploratory immunological biomarkers in plasma
      and tumor samples will evaluate immune activation.