Lynparza boosts long-term survival in early breast cancer

AstraZeneca and MSD's PARP inhibitor Lynparza has improved long-term survival when given as adjuvant therapy for early breast cancer – the first drug in the class to show that in a clinical trial.

The new data comes from the phase 3 OlympiA study that involved women with BRCA-mutated, HER2-negative breast cancer, who had surgery and chemotherapy to remove the tumour, and compared Lynparza (olaparib) to placebo as a post-surgery regimen to try to prevent the cancer from coming back.

The new analysis – presented at the San Antonio Breast Cancer Symposium (SABCS) – reveals that 87.5% of patients treated with Lynparza were alive at six years compared to 83.2% in the comparator arm, which was a statistically significant difference.

That equates to a 28% reduction in the risk of death compared to placebo, which was accompanied by a 35% cut in the risk of invasive breast cancer recurrence and the risk of distant disease recurrence or death.

OlympiA trial investigator Judy Garber of the Dana-Farber Cancer Institute described the new results as "exciting", adding that they confirm that a single year of Lynparza treatment "continues to deliver clinically meaningful survival benefit for patients with germline BRCA-mutated high-risk HER2-negative early breast cancer even after six years."

Lynparza was approved by the FDA for use in this patient population in 2022, based on data from OlympiA showing that the drug extended invasive disease-free survival (iDFS) compared to control in this challenging and aggressive form of breast cancer.

According to AZ, the data is one of the main drivers for the growth of the PARP inhibitor – which grew 10% to $2.23 billion in the first nine months of the year – along with a recent approval for metastatic prostate cancer on the back of the PROpel trial.

Lynparza is already the most widely-used PARP inhibitor, and the new results could help to extend its lead over rivals in the class like GSK's Zejula (niraparib), Pfizer's Talzenna (talazoparib), and Pharma & Schweiz's Rubraca (rucaparib).

AZ and MSD's drug – which is starting to approach the end of its patent life with generics in the US expected to appear from 2027 onwards – is, however, starting to see a slowdown in growth, so any data that encourages use in its final years of exclusivity will be welcomed by the companies.

GlobalData has predicted that the drug will reach a peak of around $4 billion in sales before generics start to appear.

Photo by National Cancer Institute on Unsplash