A Study of JZP815 Oral Capsules in Adult Participants With Advanced or Metastatic Solid Tumors Harboring Mitogen Activated Protein Kinase (MAPK) Pathway Alterations to Investigate the Safety, Dosing, and Antitumor Activity of JZP815

Must have received: standard of care therapy

Participants must have exhausted all available standard of care therapies, or in the opinion of the investigator would be unlikely to tolerate or derive clinically meaningful benefit from available standard of care therapy

Cannot have received: cancer directed therapy

Exception: For Arm 7 (NRAS Q61 mutated anaplastic thyroid cancer) in Part B (Expansion), radio-sensitizing chemotherapy (low-dose chemotherapy) permitted with a wash-out period of 7 days or 5 half-lives, whichever is shorter

Received any cancer directed therapy (chemotherapy, hormonal therapy, biologic, etc.) within 28 days or 5 half-lives (whichever is shorter) of starting study intervention

Cannot have received: radiotherapy

Exception: must have recovered from acute toxicities associated with treatment

Participants who have received radiotherapy must have recovered from acute toxicities associated with treatment

Cannot have received: investigational agent

Concurrent therapy with any other investigational agent