The US Food and Drug Administration (FDA) has granted priority review to the supplemental biologics licence application (sBLA) for Enhertu, a treatment developed by Daiichi Sankyo and AstraZeneca to treat unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-positive solid tumours.

Enhertu is an antibody-drug conjugate engineered to target HER2, a protein overexpressed in certain types of cancer.

It is intended to treat adults who have been previously treated or who lack satisfactory alternative options.

This designation is reserved for therapies that could substantially improve upon existing treatments in terms of efficacy, safety or patient compliance.

Priority review status accelerates the review process for therapies that have the potential to offer improvements in the treatment of serious ailments.

A decision on the approval under the Prescription Drug User Fee Act is expected on 30 May 2024.

The FDA's decision follows a breakthrough therapy designation awarded to Enhertu in August 2023 to treat patients with metastatic HER2-positive solid tumours.

The sBLA is under review through the regulator’s Real-Time Oncology Review programme and Project Orbis, initiatives aimed at expediting the delivery of cancer treatments to patients.

Enhertu’s application is supported by findings from the ongoing DESTINY-PanTumor02 Phase II trial, which showed that the drug provided clinically meaningful and durable responses, translating into a significant survival benefit for patients with advanced HER2-expressing solid tumours.

Additional data from other trials, including DESTINY-Lung01 and DESTINY-CRC02, which involved patients with HER2-positive IHC 3+ tumours, were also included in the sBLA submission.

Daiichi Sankyo research and development global head Ken Takeshita stated: “The clinical benefit seen across HER2-expressing metastatic solid tumours in the DESTINY-PanTumor02 trial and ongoing data from the Enhertu clinical development programme continues to demonstrate the potential of this medicine beyond its approved indications.

“If approved, ENHERTU could become the first HER2-directed therapy and antibody-drug conjugate with a tumour agnostic indication, providing patients with a potential new treatment option.”

The latest development comes after the European Commission approved Enhertu to treat advanced non-small cell lung cancer patients with a HER2 mutation.