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])