IDEAYA’s IDE161 Receives Fast Track Designation for HR+ Her2- Breast Cancer


The FDA has granted IDEAYA Biosciences fast track status for IDE161 as a treatment for HR+, Her2- breast cancer. The therapy is a selective inhibitor of ADP ribose glycohydrolase or PARG.

PARG is a major enzyme responsible for the breakdown (catabolism) of poly (ADP-ribose) glycohydrolase which is involved in DNA repair and replication.

The Pharmaceutical Business Review reports that IDE161 has been developed to treat patients who have metastatic or advanced hormone receptor-positive (HR+), Her2- breast cancer with germline (occur in eggs or cells) or somatic (occur in body cells) BRCA 1/2 mutations. Germline mutations are inherited while somatic mutations are not inherited.

A Brief Explanation

  • HR+ tumor cells with receptors for progesterone or estrogen (or both) hormones can promote HR tumor growth. This subtype is the most common as it affects approximately 65% to 75% of patients with breast cancer
  • HER2= human epidermal growth factor receptor 2

 Adult patients are eligible to participate in the study if they have been treated previously with hormonal therapy, a PARP inhibitor therapy, and a CDK4/6 inhibitor therapy.

The FDA designation is the second granted in IDEAYA’s IDE161 program.

IDE161, a first in human study, is being assessed for safety, drug metabolism (pharmacokinetics), tolerability, and effects of the drugs on the body (pharmacodynamics).

The study also involves patients with solid tumors having similar genetic engineering homologous recombination deficiency. Dose escalation studies involving prior clinical data have shown tumor shrinkage in some patients with the aforementioned condition as well as colon cancer and BRCA mutated endometrial cancer.

The Expansion Phase

The expansion portion of the Phase I study will involve patients who have ovarian cancer and HRD positive breast cancer.

Darrin Beaupre M.D., IDEAYA’s CMO, commented that the FDA’s designation for the PARG inhibitor is indicative of IDE161’s potential to meet some of the community’s unmet medical needs.


Rose Duesterwald

Rose Duesterwald

Rose became acquainted with Patient Worthy after her husband was diagnosed with Acute Myeloid Leukemia (AML) six years ago. During this period of partial remission, Rose researched investigational drugs to be prepared in the event of a relapse. Her husband died February 12, 2021 with a rare and unexplained occurrence of liver cancer possibly unrelated to AML.

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