AstraZeneca and Merck’s HER2-negative Breast Cancer Treatment Wins Yet Another Approval

On August 25, AstraZeneca and Merck announced the Japan Pharmaceuticals and Medical Devices Agency (PMDA) approved their drug LYNPARZA® (olaparib). LYNPARZA is a PARP inhibitor treating BRCA-mutated (BRCAm), human epidermal growth factor receptor 2 (HER2)-negative high recurrence risk breast cancer.

Related Article: First Targeted Therapy for HER2-Low Breast Cancer Approved by FDA

How LYNPARZA Treats HER2-low Breast Cancer

HER2 proteins are receptors on breast cells that control how the cells grow, divide, and repair themselves. Though in 10-20% of breast cancer, the gene controlling this protein fails to function correctly. As a result, the gene produces too many copies of the protein. 

On the other hand, HER2-negative breast cancer does not express abnormal levels of HER2 proteins. A critical difference between the two types is that HER2-positive cancer is typically treated with targeted therapies, while few are available for HER2-negative patients.

However, there have been recent strides in advancing the field for targeted HER2-negative therapies. For example, the U.S. Food and Drug Administration (FDA) recently approved the target trippy Enhertu (fam-trastuzumab-deruxtecan-nxki) for HER-2 negative patients. Developed by Daiichi Sankyo and AstraZeneca, Enhertu attaches to the HER2 receptor on cancer cells and releases its chemotherapy component, destroying the cancer. 

Though LYNPARZA treats the same kind of cancer, it works differently. The mutation of the BRCA gene causes breast cancer. Typically, this gene prevents breast cancer, but when damaged, it no longer provides that protection. LYNPARZA, a poly ADP-ribose polymerase (PARP) enzyme, fixes the damage in cancer and healthy cells. As a result, it is harder for cancer cells to survive. 

Due to the OlympiA trial proving LYNPARZA’s safety and efficacy, the drug won several approvals, with the latest from the PMDA.

The Results of OlympiA Convince Another Regulatory Agency

Published in The New England Journal of Medicine in June 2021, OlympiA is a Phase 3, double-blind, international trial evaluating the efficacy and safety of LYNPARZA versus placebo. Overall, the study showed that LYNPARZA provided patients with a significantly longer survival rate than those taking the placebo. The risk of invasive breast cancer recurrences, new cancers, or death saw a 42% reduction.

The outcomes of the OlympiA trial resulted in the FDA’s approval of LYNPARZA for the treatment of BRCAm HER2-negative patients on March 11 of this year. Soon after, the European Union (EU) followed suit on August 4. Today, Japan’s PMDA followed suit, and LYNPARZA won yet another approval. 

On the PMDA’s decision, Dr Eliav Barr, senior vice president, head of global clinical development and chief medical officer at Merck Research Laboratories, said, “With this approval, LYNPARZA becomes the first and only PARP inhibitor available for patients with BRCA-mutated, HER2-negative early breast cancer in Japan. This further reinforces the critical need to conduct BRCA testing at the point of diagnosis so that all eligible patients can be identified.”

Author

Max Heirich