The U.S. Food and Drug Administration (FDA) has postponed making a decision on Lynparza for metastatic castration-resistant prostate cancer (mCRPC), which is bad news for AstraZeneca and Merck.
According to Merck, the agency will now make the decision in March, so as to give itself more time to fully review the application.
Parathyroid hormone-related protein (PARP) inhibitor Lynparza is recommended for patients with mCRPC, in conjunction with the androgen inhibitor Zytiga from Johnson & Johnson and the steroid prednisone. Prednisone can also be used alone in this regard.
Developed and marketed in tandem by AstraZeneca and MSD, Lynparza has already been used to successfully treat over 75,000 people around the world. The companies are collaborating on a comprehensive clinical trial development program for Lynparza to learn how the drug may affect multiple PARP-dependent tumors.
Supporting the application is data from the PROpel phase 3 trial, which found that the combination was superior to the current gold standard of care (Zytiga plus prednisone) in preventing disease progression – the risk of disease progression was reduced by nearly 34%. Incorporating Lynparza further prolonged survival by over eight months.
In May 2020, the FDA approved Lynparza for use in treating prostate cancer in patients who had previously been treated but who possessed mutations in their homologous recombination repair (HRR) genes. The FDA initially green-lit the drug in 2014 to treat ovarian cancer; subsequent approvals followed in 2018 for breast cancer and 2019 for pancreatic cancer.
In 2021, Lynparza helped AZ bring in $2.75 billion, up 21% from the year before. According to Merck, the drug generated nearly $990 million in revenue in 2016, up 36% from the previous year.
In the battle against prostate cancer, Lynparza has an established advantage over GSK and J&J’s Zejula. J&J is attempting to get Zejula approved for use in prostate cancer, but the drug has not yet been given the green light.
Analysts with SVB Securities mentioned after the announcement that “given some of the emerging concerns for the PARP inhibitor class, we think it is possible the FDA asked AZN for more information on OS data/trends, including for the HRD- subgroup, where the asset may be less efficacious.” The analysts went on to speculate that the FDA may be wary of the risk/benefit ratio of the PARP class for certain patient subsets.
Metastatic prostate cancer is linked to a high death rate. The androgen hormones play a significant role in the progression of prostate cancer.
Even though androgen-deprivation therapy is used to stop the growth and spread of prostate cancer in patients with mCRPC, the cancer continues to develop and spread to other body parts.
Between 10 and 20% of men suffering from advanced prostate cancer will see it progress to castration-resistant prostate cancer within a period of five years. At the time of their CRPC diagnosis, nearly 85% of these men will already have metastases. For patients who haven’t developed metastases at CRPC diagnosis, one-third have a high likelihood to get it within two years.