A Phase I Study of RLY-2608 Alone in People with Solid Tumors or in Combination with Fulvestrant in People with Breast Cancer

Full Title

A First-in-Human Study of Mutant-selective PI3Ka Inhibitor, RLY-2608, as a Single Agent in Patients with Advanced Solid Tumors and in Combination with Endocrine Therapy +/- a CDK4/6 or CDK4 Inhibitor in Patients With Advanced Solid Tumors or Advanced Breast Cancer

Purpose

The purpose of this study is to find the highest dose of the investigational drug RLY-2608 that can be used alone in people with advanced solid tumors and with fulvestrant in people with advanced breast cancer. Participants in this study will have cancers that contain a mutation in a gene called PIK3CA. Their cancers must have continued to grow despite treatment or be inoperable.

RLY-2608 works by targeting and blocking a protein called PI3K, which promotes cancer growth and spread in people with a PIK3CA mutation. RLY-2608 is a capsule that is taken orally (by mouth). Fulvestrant is a standard hormonal treatment for certain types of breast cancer and is given by injection.