Blocking antibodies targeting PD-1 have achieved remarkable results in the treatment of many
      types of tumors. However, based upon the rate of primary and secondary resistance to PD-1
      blockade, it is apparent that additional immuno-regulatory mechanism(s) underlie tumor immune
      escape. Indeed, research shows that the TIM-3 pathway cooperates with PD-1 to maximize the
      suppression of effector TILs as well as promote resistance to anti-PD-1 therapy. Therefore,
      TIM-3 represents an ideal target with the potential to significantly improve and/or extend
      the therapeutic benefit of anti-PD-1 therapy to a greater number of patients.

      TIM-3 and PD-1 function as immune checkpoint receptors in the overlapping regulation of
      immune tolerance and have been shown to be overexpressed on the tumor infiltrating
      lymphocytes (TILs) from participant samples of various solid tumors including, but not
      limited to non-small cell lung cancer, head and neck squamous cell carcinoma, renal cell
      carcinoma, hepatocellular carcinoma, and gastric carcinoma. Subsequently, the activation of
      TIM-3 and PD-1 represent TILs from both participants or animals across solid tumor types with
      the most exhausted immunophenotype (ie, cytokine expression, proliferation etc.), which can
      be reversed with combined blockade of TIM-3 and PD 1. The overlap in expression and function
      indicates that TIM-3 and PD-1 cooperate to promote effector cell exhaustion which may impede
      an effective antitumor immune response. Based upon the overlapping expression profiles and
      immuno-regulatory functions, the improved in vivo antitumor effects, as well as the potential
      for TIM-3 mediated adaptive resistance, there is strong scientific rationale to evaluate the
      antitumor effects derived from the combined blockade of TIM-3 and PD-1 in advanced solid
      tumors. Accordingly, this study will evaluate the safety and preliminary efficacy of BGB-A425
      (anti TIM-3) in combination with tislelizumab (anti PD-1) in participants with advanced solid
      tumors.

      This is an open-label, multicenter, nonrandomized Phase 1 and Phase 2 clinical trial. Phase 1
      will determine the Recommended Phase 2 Dose (RP2D) for the combination of BGB-A425 and
      tislelizumab. Phase 2 will continue to evaluate the safety but also focus on the efficacy of
      the combination in select tumor types.