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

Known uncontrolled brain metastases. Stable brain metastases either treated or being treated with a stable dose of steroids/anticonvulsants, with no dose change in the previous 4 weeks, are permitted

Active fungal, bacterial and/or known viral infection including HIV or Hepatitis A, B, C

Concomitant malignancies or previous malignancies with less than 2 years disease-free interval at the time of enrollment, with the exception of non-metastatic, non-melanomatous skin cancers, carcinoma in-situ, melanoma in-situ, prostate cancer with undetectable PSA, indolent thyroid cancer that are adequately treated

Has clinically significant (ie, active) cardiovascular disease: cerebral vascular accident/stroke (\< 6 months prior to enrollment), myocardial infarction (\< 6 months prior to enrollment), unstable angina, congestive heart failure (\> New York Heart Association Classification Class II), QTc ≥ 470 msec, or serious cardiac arrhythmia requiring medication

Uncontrolled or severe intercurrent medical condition

Gastrointestinal condition that could impair absorption of study intervention or inability to ingest study intervention

In the judgement of the investigator, any important medical illness or abnormal laboratory finding that would increase the risk of participating in this study

Received any cancer directed therapy (chemotherapy, hormonal therapy, biologic, etc.) within 28 days or 5 half-lives (whichever is shorter) of starting study intervention. For Arm 7 (NRAS Q61 mutated anaplastic thyroid cancer) in Part B (Expansion), participants who have received radio-sensitizing chemotherapy (low-dose chemotherapy) are permitted a wash-out period of 7 days or 5 half-lives, whichever is shorter (a discussion with the sponsor is required). Participants who have received radiotherapy must have recovered from acute toxicities associated with treatment.

Use of any products or medicines known to be strong or moderate inducers or inhibitors of CYP3A4, which cannot be discontinued at least 4 weeks or 5 half-lives (whichever is shorter) before starting study intervention, or planned use at any time during the study

Use of proton pump inhibitors (eg, omeprazole) and histamine-2 receptor antagonists (eg, famotidine), which cannot be discontinued at least 2 weeks before first dose, or planned use at any time during the study

Concurrent therapy with any other investigational agent

What this study is about