GBR 1302 is a therapy that Glenmark Pharmaceuticalsk is developing to treat cancers containing a protein known as human epidermal growth factor 2, or HER2.
These include breast cancer, gastric cancer, and cancers of the esophagus, ovaries and endometrium, or membrane lining the uterus.
How GBR 1302 works
GBR 1302 is a manmade antibody that targets HER2 and a protein known as cluster of differentiation 3, or CD3.
HER2 helps control the way normal cells grow, divide, and repair themselves. But in cancer cells, it does not work correctly, making too many copies of itself. This leads to cells growing and dividing in an uncontrollable way.
CD3 is found on the surface of several types of immune T-cells. It helps activate the T-cells so they can respond to infections or diseases such as cancer.
GBR 1302 is known as a bispecific monoclonal antibody because scientists produce it in a laboratory to bind to two targets — the HER2 protein that a number of cancer cells over-produce and the CD3 protein found on the surface of T-cells.
By binding to both targets at the same time, GBR 1302 recruits killer T-cells to the locations of cancer that contain HER2 so they can kill the cancer.
GBR 1302 is the first therapy that Glenmark developed with a proprietary technology it calls BEAT — for bispecific engagement of antibodies based on the T cell receptor. It is the first technology that allows scientists to produce bispecific antibodies in large quantities.
GBR 1302 in clinical trials
After extensive studies of GBR 1302 in the laboratory, Glenmark moved it to a Phase 1 clinical trial in 2016.
The lab studies showed that GBR 1302 does a better and faster job of killing tumors containing HER2 than other antibody-based therapies, including Herceptin (trastuzumab) and Perjeta (pertuzumab).
Glenmark presented the findings at the 4th European Society of Medical Oncology Symposium on Immuno-Oncology in Lausanne, Switzerland, in November 2016. Researchers said GBR 1302 showed punch against breast, gastric and other cancers.
Another plus was that it activated T-cells only when binding with cancer cells, researchers said. This suggested it would be safe, because activating T-cells in other situations could be harmful.
The Phase 1 trial (NCT02829372) is testing GGBR 1302 in patients with several types of tumors that contain HER2. The study, which started in July 2016, continues to recruit participants at four sites in Germany. Glenmark plans to expand the trial to the United States later.
There are two parts to the study. In the first part, patients who were previously treated with other therapies receive one of several doses of GBR 1302. The goal is to determine a maximum tolerated dose.
In the second part, researchers will give the optimal dose to the same patients who took part in part one. The objectives are to see how effective the dose is, and whether it is safe.
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