This is a multi-center, first-in-human (FIH), open-label, Phase 1a/1b dose escalation and dose expansion study to assess the safety, PK, pharmacodynamics, and antitumor activity of PHST001 monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b) in adult participants with advanced relapsed and/or refractory solid tumors (including but not limited to CNS tumors in Phase 1a only). In Phase 1b cohort expansions, the study will focus on participants with advanced relapsed and/or refractory ovarian cancer, endometrial cancer, and cholangiocarcinoma. The study's primary objective is to evaluate the safety and tolerability of PHST001 and determine the RP2D (Recommended Phase 2 dose) of PHST001 monotherapy and in combination with chemotherapy as well as assess the anti-tumor activity of PHST001 and chemotherapy in Phase 1b.

This phase II trial tests how well evaluating circulating tumor deoxyribonucleic acid (ctDNA) works to guide therapy-change decisions in treating patients with triple-negative breast cancer (TNBC) that has spread from where it first started (primary site) to other places in the body (metastatic). This study wants to learn if small pieces of DNA associated with a tumor (called circulating tumor DNA, or ctDNA) can be detected in investigational blood tests during the course of standard chemotherapy treatment for breast cancer, and whether information from such investigational ctDNA blood testing could possibly be used as an early indication of chemotherapy treatment failure. It is hoped that additional information from investigational blood testing for ctDNA could help doctors to switch more quickly from a standard chemotherapy treatment that typically has significant side effects and which may not be working, to a different standard treatment regimen against TNBC, called sacituzumab govitecan. Sacituzumab govitecan is a monoclonal antibody, called hRS7, linked to a chemotherapy drug, called irinotecan. hRS7 is a form of targeted therapy because it attaches to specific molecules (receptors) on the surface of cancer cells, known as TROP2 receptors, and delivers irinotecan to kill them. Studying ctDNA may assist doctors to change therapy earlier if needed, and may improve health outcomes in patients with metastatic TNBC.

This phase III trial compares the effect of decreased number of radiation (ultra-hypofractionated) treatments to the usual radiation number of treatments (hypofractionation) with standard of care chemotherapy, with cisplatin, gemcitabine or mitomycin and 5-fluorouracil for the treatment of patients with muscle invasive bladder cancer. Hypofractionated radiation therapy delivers higher doses of radiation therapy over a short period of time. Ultra-hypofractionated radiation therapy delivers radiation over an even shorter period of time than hypofractionated radiation therapy. Cisplatin is in a class of medications known as platinum-containing compounds. It works by killing, stopping or slowing the growth of tumor cells. Gemcitabine is a chemotherapy drug that blocks the cells from making DNA and may kill tumor cells. Chemotherapy drugs, such as mitomycin-C and 5-fluorouracil (5-FU), work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving ultra-hypofractionated radiation may be equally effective as hypofractionated therapy for patients with muscle invasive bladder cancer.

This is a Phase 1, open-label, multicenter, study of the safety, tolerability, PK, PD, and anti-tumor activity of MRTX1719 patients with advanced, unresectable or metastatic solid tumor malignancy with homozygous deletion of the MTAP gene.

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.