Study of DCC-3084 in Participants With Advanced Malignancies Driven by the Mitogen-Activated Protein Kinase (MAPK) Pathway

• DCC-3084 (Drug): Administered orally

Primary outcomes

• Number of Participants with Dose-limiting Toxicities (DLTs) (ModA Part 1) [Cycle 1 (28 days)]: DLTs reported during ModA Part 1.
• Objective Response Rate (ORR) (ModA Part 2) [Start of Therapy to Progressive Disease (PD), Death Due to Any Cause, or Start of New Antitumor Therapy (Estimated up to 24 months)]: ORR is the percentage of participants with confirmed complete or partial remission based on indication specific criteria as defined in the protocol.

Secondary outcomes

• ORR (ModA Part 1) [Start of Therapy to PD, Death Due to Any Cause, or Start of New Antitumor Therapy (Estimated up to 24 months)]: ORR is the percentage of participants with confirmed complete or partial remission based on indication specific criteria as defined in the protocol.
• Progression-Free Survival (PFS) (ModA Part 1 and 2) [Start of Therapy to PD or Death Due to Any Cause (Estimated up to 24 months)]: PFS is the time from start of therapy to PD or death due to any cause.
• Overall Survival (OS) (ModA Part 1 and 2) [Start of Therapy to Death Due to Any Cause (Estimated up to 36 months)]: OS is the time from start of therapy to death from any cause.
• Pharmacokinetics (PK): Maximum observed plasma drug concentration (Cmax) (ModA Part 1 and 2) [Predose up to 12 hours postdose]: Cmax (ModA Part 1 and 2)

Sex: All, ages: 18 Years to any

Inclusion Criteria:

General Inclusion Criteria ModA Part 1 and 2:

* Able to take oral medication
* If a female is of childbearing potential, must have a negative pregnancy test prior to enrollment and all participants agree to follow the contraception requirements
* Adequate organ function and electrolytes
* Eastern Cooperative Oncology Group Performance Status (ECOG-PS) of 0 to 1 at Screening
* Has a life expectancy of more than 6 months
* In addition to these general inclusion criteria, participants must meet all the module cohort-specific inclusion criteria

Inclusion Criteria ModA Part 1 Cohort Specific:

* Pathologically confirmed diagnosis of solid cancer and documentation of Kirsten rat sarcoma (KRAS), Harvey rat sarcoma virus (HRAS), neuroblastoma ras viral oncogene homolog (NRAS), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), v-raf murine sarcoma viral oncogene homolog C1(CRAF), and/or neurofibromatosis 1 (NF1) mutation
* Have exhausted all available standard of care therapies that are known to provide benefit for the participant's condition, as judged by the Investigator

Inclusion Criteria ModA Part 2 Cohort Specific:

* Documented BRAF gene mutation
* Pathologically confirmed diagnosis with PD after at least one prior line of therapy in the advanced or metastatic setting

Exclusion Criteria:

General Exclusion Criteria ModA Part 1 and 2:

* Prior treatment with certain BRAF dimer inhibitors
* Female participant is pregnant or lactating
* Received any prior or concurrent medications or therapies known to be prohibited with DCC-3084 within 14 days
* Received any prior antitumor therapy or any investigational therapy within a specified timeframe prior to first dose of DCC-3084
* Known allergy or hypersensitivity to any component of the study drug
* Invasive malignancy within 2 years prior to the first dose of study drug other than the study indication or specific types of cancer treated with curative intent
* Have not recovered from all clinically relevant toxicities from prior therapy
* Impaired cardiac function
* History of recent thrombotic or embolic events
* Malabsorption syndrome or other illness that could affect oral absorption
* Major surgery within 28 days of the first dose of study drug
* In addition to the general exclusion criteria, participants will also be excluded based on the cohort-specific exclusion criteria

Exclusion Criteria: Module A Part 2 Cohort Specific:

• Has known co-occurring mutation of KRAS, HRAS, NRAS, NF1, epidermal growth factor receptor, Phosphoinositide-3-kinase, catalytic, alpha polypeptide (PI3KCA), or Phosphatase and TENsin homolog deleted on chromosome 10 (PTEN)