AstraZeneca's Lynparza (olaparib), a poly ADP-ribose polymerase (PARP) inhibitor, has been added to the Korean Breast Cancer Society’s (KBCS) practice guidelines, two months after expanding its indication to postoperative adjuvant therapy in adult patients with breast cancer in Korea.

Last month, the KBCS released the 10th Korean Breast Cancer Treatment Recommendations, which includes the latest treatment guidelines for breast cancer, including adjuvant therapy after lumpectomy.

In the revised recommendation, Lynparza has been updated to the Level of Evidence 1, Class of Recommendation A for postoperative adjuvant therapy in HER2-negative early-stage breast cancer with gBRCA mutations.

Lynparza's expanded indication and the speedy recommendation update came because Lynparza is the first and only PARP inhibitor to demonstrate improved overall survival (OS) in gBRCA-mutated, HER2-negative, high-risk early-stage breast cancer.

In the phase 3 OlympiA study of HER2-negative early-stage breast cancer patients with gBRCA1/2 mutations who had completed local therapy and upfront or adjuvant chemotherapy, Lynparza as postoperative adjuvant therapy demonstrated a statistically significant improvement in invasive disease-free survival (IDFS). The proportion of patients in the Lynparza adjuvant arm who were free of invasive breast cancer recurrence at three years was 85.9 percent, compared to 77.1 percent in the placebo arm.

Lynparza as postoperative adjuvant therapy reduced the risk of breast cancer recurrence or death by 42 percent, compared with placebo, and the risk of death by 32 percent, compared with placebo, over a median follow-up of 3.5 years, confirming a significant improvement in OS.

Lynparza's 4-year IDFS was 82.7 percent compared to 75.4 percent in the placebo arm, and distant disease-free survival (DDFS) was also significantly improved at 86.5 percent in the Lynparza arm and 79.1 percent in the placebo arm.

Based on these findings, the 10th Korean Breast Cancer Treatment Recommendations states that adjuvant olaparib for one year after completion of upfront or adjuvant chemotherapy, surgery, and radiotherapy is indicated for HER2-negative breast cancer with gBRCA mutations.

In other countries, there is also strong interest in Lynparza as postoperative adjuvant therapy for gBRCA mutations. The American Society of Clinical Oncology (ASCO) quickly revised its guidelines to include adjuvant Lynparza for one year after preoperative chemotherapy or postoperative adjuvant therapy for hormone receptor-positive/HER2-negative and triple-negative breast cancer patients with BRCA 1/2 mutations at high risk of recurrence.

The latest NCCN (National Comprehensive Cancer Network) guidelines also recommend Lynparza first for HER2-negative breast cancer patients with gBRCA mutations.

"Olaparib has demonstrated OS improvement in HER2-negative high-risk early breast cancer patients with gBRCA mutations," said Professor Sohn Joo-hyuk at the Oncology Department at Severance Hospital. "The medical evidence (for Lynparza) is strong as the study was a phase 3 trial and showed a 42 percent improvement in the risk of recurrence and death."

The problem is that Lynparza is not covered by health insurance in Korea, Sohn added.

“The inclusion of Lynparza in the recommendations was only natural because treatments that can reduce recurrence should be applied in clinical practice.”