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 Advanced Solid Tumor Patients and in Combination with Fulvestrant in Patients With Advanced Breast Cancer


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.

Who Can Join

To be eligible for this study, patients must meet several requirements, including:

  • Participants must have an advanced solid tumor or breast cancer which contains a PIK3CA mutation.
  • Patients’ cancers must persist despite treatment or be unable to be removed with surgery.
  • At least 2 weeks must pass between the completion of prior treatments and receipt of the study therapy.
  • Patients must be physically well enough that they are able to be mobile, take care of themselves, and engage in all but physically strenuous activities. For example, they must be well enough that they could carry out office work or light housework.
  • This study is for people age 18 and older.

For more information and to ask about eligibility for this study, please call 646-888-4226.




Phase I (phase 1)

Disease Status

Newly Diagnosed & Relapsed/Refractory



ClinicalTrials.gov ID