The U.S. Food and Drug Administration granted accelerated approval to AstraZeneca PLC and Daiichi Sankyo Co. Ltd.'s Enhertu for the treatment of certain breast cancer patients who are ineligible for surgery.

Enhertu's application received priority review in October, and has now been approved three months ahead of schedule. The FDA originally planned to respond to the application by the second quarter of 2020.

The drug regulator approved Enhertu, or trastuzumab deruxtecan, to treat patients with human epidermal growth factor receptor 2-positive breast cancer that has spread across the body or has metastasized after receiving two or more therapies. The FDA said the approval is based on a phase 2 clinical trial called Destiny-Breast01, which showed positive results in patients with this type of breast cancer.

AstraZeneca and Daiichi Sankyo are developing the cancer treatment through a partnership agreement. British pharmaceutical giant AstraZeneca paid Daiichi Sankyo $1.35 billion upfront to share costs and profits for the development and commercialization of Enhertu worldwide, excluding Japan. Tokyo-based Daiichi Sankyo is solely responsible for the manufacturing and supply of Enhertu.

The drug previously received breakthrough therapy and fast track designations from the FDA for treating patients with HER2-positive breast cancer that is locally advanced or has spread to other organs.