This is an umbrella study evaluating the efficacy and safety of multiple treatment combinations in participants with metastatic or inoperable locally advanced breast cancer.

The study will be performed in two stages. During Stage 1, six cohorts will be enrolled in parallel in this study:

Cohort 1 will consist of programmed death-ligand 1 (PD-L1)-positive participants who have received no prior systemic therapy for metastatic or inoperable locally advanced triple-negative breast cancer (TNBC) (first-line \[1L\] PD-L1+ cohort).

Cohort 2 will consist of participants who had disease progression during or following 1L treatment with chemotherapy for metastatic or inoperable locally-advanced TNBC and have not received cancer immunotherapy (CIT) (second-line \[2L\] CIT-nave cohort).

Cohort 3, 5, and 6 will consist of participants with locally advanced or metastatic hormone receptor-positive (HR+), human epidermal growth factor receptor 2 (HER2)-negative disease with one or more PIK3CA mutations.

Cohort 4 will consist of participants with locally advanced or metastatic HER2+ /HER2-low disease with one or more PIK3CA mutations who had disease progression on standard-of-care therapies (HER2+ /HER2-low cohort).

In each cohort, eligible participants will initially be assigned to one of several treatment arms (Stage 1). During Stage 2, participants in the 2L CIT-nave cohort who experience disease progression, loss of clinical benefit, or unacceptable toxicity during Stage 1 may be eligible to continue treatment with a different treatment combination, provided Stage 2 is open for enrollment and all eligibility criteria are met.

This study is exploring the use of Panitumumab in Head and Neck Cancer. Panitumumab is an approved drug named Vectibix and is used as an anti-cancer agent in other cancers such as colorectal cancer. It works by attaching to the cancer cell in a unique way that allows the drug to get into the cancer tissue. In addition to the Panitumumab, participants will also receive a Panitumumab-IRDye800 (Pan800) or a fluorescently labeled Panitumumab infusion. IRDye800 is an investigational dye that, when tested in the lab, helps various characteristics of human tissue show up better when using a special camera during surgery. Panitumumab-IRDye800 is a combination of the drug and the dye that attaches to cancer cells and appears to make them visible to the doctor when he or she uses the special camera during surgery.

The goal of this study is to use a novel and possibly safer approach to identify an optimal dose for panitumumab to treat cancer patients by using a new light-based therapy. In this study, different drug levels will be analyzed using this approach to understand how much drug reaches the tumor at different administered doses, which may help us provide safer and/or more effective therapies in the future.

The goal is to identify the correct amount or dose of a drug that is needed for effective cancer therapies. Often, clinical studies look at how much of the drug can be tolerated before patients become sick, rather than how much of the drug is required to be effective.

IRDye800 is an investigational dye that, when tested in the lab, helps various characteristics of human tissue show up better when using a special camera during surgery. Panitumumab-IRDye800 is a combination of the drug and the dye that attaches to cancer cells and appears to make them visible to the doctor when he or she uses the special camera during surgery. This will help the surgeon with clinical margins during surgery and will may have a clearer way to differentiate between cancer and healthy tissue.

This phase I/II trial studies the side effects and best dose of temozolomide and M1774 and how well they works in treating patients with cancer that has spread from where it first started (primary site) to other places in the body (metastatic) and may have spread to nearby tissue, lymph nodes, or distant parts of the body (advanced). Temozolomide is in a class of medications called alkylating agents. It works by damaging the cell's deoxyribonucleic acid (DNA) and may kill tumor cells and slow down or stop tumor growth. M1774 may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Adding M1774 to temozolomide may shrink or stabilize cancer for longer than temozolomide alone.