ETBX-021 is an immunotherapy that Etubics is developing for breast cancer.

How ETBX-021 works

ETBX-021 is a type of immunotherapy called a cancer vaccine. The name comes from the fact that it stimulates the immune system to recognize and attack cancer cells.

The therapy helps the immune system recognize tumor-associated antigens, which are substances that would not normally be found in the body. The body then produces immune cells, such as T-cells, that target the antigens to find and kill tumor cells.

ETBX-021 is designed to make the immune system target the HER2 protein, which is commonly found at high levels in breast cancer tumors. It consists of a virus called adenovirus 5 (Ad5), which has been modified so it contains an HER2 gene. The virus is also modified not to be harmful, but to still be recognized by the immune system as foreign.

The therapy leads to the production of cytotoxic, or cell-killing, T-cells against HER2, resulting in the death of the tumor cells.

ETBX-021 in clinical trials

Preclinical-trial studies conducted in mice, and published in the journal Cancer Gene Therapy, demonstrated that ETBX-021 was able to trigger an immune response in mice, significantly slowing tumor growth.

A Phase 1 clinical trial (NCT02751528) that Etubics is conducting with NantBioScience — part of Nantworks  —  is recruiting participants with unresectable advanced breast cancer at a site in South Dakota. An unresectable cancer is one that cannot be completely removed by surgery.

The study will involve an initial dose escalation to find a maximum tolerated dose of ETBX-021. The aim is to evaluate the therapy’s safety, effectiveness, and ability to trigger an immune response. The trial is expected to be completed by December 2020.

ETBX-021 will also be assessed along with a range of other immunotherapies in the QUILT program. The therapy-combination trials that are part of this program are aimed at harnessing all of the elements of the immune system. The trials will test combinations of immunotherapies in up to 20 tumor types, such as breast, lung, prostate, ovarian, brain, head and neck, multiple myeloma, sarcoma, and pancreatic cancers.


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