This phase Ib trial tests the safety and tolerability of ZEN003694 in combination with an immunotherapy drug called pembrolizumab and the usual chemotherapy approach with nab-paclitaxel for the treatment of patients with triple negative-negative breast cancer that has spread to other parts of the body (advanced). Paclitaxel is in a class of medications called antimicrotubule agents. It stops cancer cells from growing and dividing and may kill them. Nab-paclitaxel is an albumin-stabilized nanoparticle formulation of paclitaxel which may have fewer side effects and work better than other forms of paclitaxel. Immunotherapy with monoclonal antibodies, such as pembrolizumab may help the body's immune system attach the cancer and may interfere with the ability of tumor cells to grow and spread. ZEN003694 is an inhibitor of a family of proteins called the bromodomain and extra-terminal (BET). It may prevent the growth of tumor cells that over produce BET protein. Combination therapy with ZEN003694 pembrolizumab immunotherapy and nab-paclitaxel chemotherapy may help shrink or stabilize cancer for longer than chemotherapy alone.

This phase II ADC MATCH screening and multi-sub-study treatment trial is evaluating whether biomarker-directed treatment with one of three antibody-drug conjugates (ADCs) (sacituzumab govitecan, enfortumab vedotin, and trastuzumab deruxtecan) works in treating patients with solid tumor cancers that have high expression of the Trop-2, nectin-4, or HER2 proteins and that may have spread from where they first started (primary site) to nearby tissue, lymph nodes, or distant parts of the body (advanced) or to other places in the body (metastatic). Precision medicine is a form of medicine that uses information about a person's genes, proteins, and environment to prevent, diagnose, or treat disease in a way that is tailored to the patient. ADCs such as sacituzumab govitecan, enfortumab vedotin, and trastuzumab deruxtecan are monoclonal antibodies attached to biologically active drugs and are a form of targeted therapy. Sacituzumab govitecan is a monoclonal antibody, called sacituzumab, linked to a drug called govitecan. Sacituzumab attaches to a protein called Trop-2 on the surface of tumor cells and delivers govitecan to kill them. Enfortumab vedotin is a monoclonal antibody, enfortumab, linked to an anticancer drug called vedotin. It works by helping the immune system to slow or stop the growth of tumor cells. Enfortumab attaches to a protein called nectin-4 on tumor cells in a targeted way and delivers vedotin to kill them. Trastuzumab deruxtecan is composed of a monoclonal antibody, called trastuzumab, linked to a chemotherapy drug, called deruxtecan. Trastuzumab attaches to HER2 positive tumor cells in a targeted way and delivers deruxtecan to kill them. Personalized treatment with sacituzumab govitecan, enfortumab vedotin, or trastuzumab deruxtecan may be an effective treatment option for patients with advanced or metastatic solid tumors that screen positive for high expression of Trop-2, nectin-4, or HER2, respectively.

This ComboMATCH patient screening trial is the gateway to a coordinated set of clinical trials to study cancer treatment directed by genetic testing. Patients with solid tumors that have spread to nearby tissue or lymph nodes (locally advanced) or have spread to other places in the body (advanced) and have progressed on at least one line of standard systemic therapy or have no standard treatment that has been shown to prolong overall survival may be candidates for these trials. Genetic tests look at the unique genetic material (genes) of patients' tumor cells. Patients with some genetic changes or abnormalities (mutations) may benefit from treatment that targets that particular genetic mutation. ComboMATCH is designed to match patients to a treatment that may work to control their tumor and may help doctors plan better treatment for patients with locally advanced or advanced solid tumors.

This is a randomized, open-label study comparing the efficacy and safety of adjuvant sacituzumab tirumotecan (MK-2870) in combination with pembrolizumab compared to treatment of physician's choice (TPC) in participants with triple-negative breast cancer (TNBC) who received neoadjuvant therapy and did not achieve a pathological complete response (pCR) at surgery. The primary objective is to compare sacituzumab tirumotecan plus pembrolizumab to TPC (pembrolizumab or pembrolizumab plus capecitabine) with respect to invasive disease-free survival (iDFS) per investigator assessment. It is hypothesized that sacituzumab tirumotecan plus pembrolizumab is superior to TPC with respect to iDFS per investigator assessment.

This study will evaluate the efficacy and safety of the combination of inavolisib plus a cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i) and letrozole versus placebo plus a CDK4/6i and letrozole in the first-line setting in participants with endocrine-sensitive PIK3CA-mutated hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-), advanced breast cancer (ABC).

This is a Phase 1b open-label, 2-part study in 3 treatment groups. The 3 treatment groups are as follows:

Treatment Group 1: Palazestrant (OP-1250) in combination with ribociclib (KISQALI, Novartis Pharmaceuticals Corporation).

Treatment Group 2: Palazestrant (OP-1250) in combination with alpelisib (PIQRAY, Novartis Pharmaceuticals Corporation).

Treatment Group 3: Palazestrant (OP-1250) in combination with everolimus.

Treatment Group 4: Palazestrant (OP-1250) in combination with atirmociclib.

This phase III trial compares the effect of continuation of treatment with pembrolizumab (usual approach) to observation only at preventing cancer from coming back in patients with early-stage triple-negative breast cancer (TNBC) who achieved a pathologic complete response after preoperative chemotherapy in combination with pembrolizumab. The usual approach for patients with early-stage TNBC who receive preoperative chemotherapy plus pembrolizumab is to continue to receive pembrolizumab for up to 27 weeks after surgery. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. This trial may help researchers determine if observation is as good as receiving pembrolizumab for 27 weeks after surgery in triple-negative breast cancer patients who achieved a pathologic complete response after preoperative treatment with chemotherapy and pembrolizumab.

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 open-label research study is studying (Z)-endoxifen as a possible treatment for pre-menopausal women with ER+/HER2- breast cancer. (Z)-endoxifen belongs to a group of drugs called selective estrogen receptor modulators or "SERM", which help block estrogen from attaching to cancer cells. This study has two parts: a pharmacokinetic part and a treatment part.

The PK part (how the body processes the drug) will enroll about 18 participants. All participants will take (Z)-endoxifen capsules daily. Twelve participants will be randomly assigned (50/50 chance) to take (Z)-endoxifen alone or (Z)-endoxifen with a monthly injection of goserelin a drug that temporarily stops the ovaries from making estrogen. This part will help determine the best dose of (Z)-endoxifen by measuring the drug levels in the blood and how long the body takes to remove it.

The Treatment Cohort has been simplified to a single study arm (Z)-endoxifen + goserelin. Up to 20 participants will be enrolled that have a baseline Ki-67 10% and 45 participants will be enrolled that have a baseline Ki-67\>10%.

A key goal of the study is to see if (Z)-endoxifen can slow down or stop tumor growth as measured by a reduction in Ki-67 levels. Tumor tissue samples will be taken by breast biopsy after about 4 weeks of treatment to check levels of this biomarker. If the tumor shows signs of response, participants can continue treatment for up to 24 weeks or until they have surgery.

Study participation is up to 6 months (24 weeks of treatment) followed by surgery and a one-month follow up visit.

The purpose of this study is to test the safety and effectiveness of the sequence of two investigational drugs (trastuzumab deruxtecan followed by datopotamab deruxtecan, or datopotamab deruxtecan followed by trastuzumab deruxtecan) to learn whether the treatment works in treating HER2-negative (HER2-low or HER2-0) metastatic breast cancer.

The names of the study drugs involved in this study are:

* Datopotamab deruxtecan (a type of antibody drug conjugate)
* Trastuzumab deruxtecan (a type of antibody drug conjugate)