Inclusion Criteria:

          -  Advanced or metastatic solid or primary CNS tumor which has failed standard of care
             therapies

          -  Evidence of an activating RET gene alteration in the tumor and/or blood

          -  Measurable or non-measurable disease

          -  Karnofsky (participants 16 years and older) or Lansky (participants younger than 16)
             performance score of at least 50

          -  Participant with primary CNS tumors or cerebral metastases must be neurologically
             stable for 7 days prior and must not have required increasing doses of steroids within
             the last 7 days

          -  Adequate hematologic, hepatic and renal function.

          -  Ability to receive study drug therapy orally or via gastric access

          -  Willingness of men and women of reproductive potential to observe conventional and
             effective birth control

        Exclusion Criteria:

          -  Major surgery within two weeks prior to planned start of LOXO-292

          -  Clinically significant, uncontrolled cardiac, cardiovascular disease or history of
             myocardial infarction within 6 months prior to planned start of LOXO-292

          -  Active uncontrolled systemic bacterial, viral, fungal or parasitic infection

          -  Clinically significant active malabsorption syndrome

          -  Pregnancy or lactation

          -  Uncontrolled symptomatic hyperthyroidism or hypothyroidism (i.e. the participant
             required a modification to current thyroid medication in the 7 days before start of
             LOXO-292)

          -  Uncontrolled symptomatic hypercalcemia or hypocalcemia

          -  Known hypersensitivity to any of the components of the investigational agent, LOXO-292
             or Ora-Sweet® SF and OraPlus®, for participants who will receive LOXO-292 suspension

          -  Prior treatment with a selective RET inhibitor(s) (including investigational selective
             RET inhibitor[s])