The FDA has granted a fast track designation to the investigational antibody-drug conjugate (ADC) ARX788 for use as a monotherapy in the treatment of patients with advanced or metastatic HER2-positive breast cancer who have previously received 1 or more HER2-targeted regimens in the metastatic setting.The decision was based on data from phase 1 trials that evaluated the safety and tolerability of the agent, along with its preliminary efficacy and pharmacokinetic profile.

“This is an important milestone for ARX788 that underscores the strong unmet medical need to develop new and effective treatment options for [patients with] breast cancer whose tumors progressed on currently approved HER2-directed regimens,” Joy Yan, MD, PhD, chief medical officer of Ambrx, stated in a press release. “It’s our mission to drive science forward to help bring innovative therapeutic options to [patients with] cancer and we look forward to working closely with the FDA to optimize and expedite the development of ARX788.”

The novel, site-specific ADC is comprised of a HER2-targeted monoclonal antibody that is linked to the cytotoxic payload AS269, which is a strong tubulin inhibitor. Proprietary technology allows for the incorporation of a non-natural amino acid into a predetermined site on the heavy chain of the monoclonal antibody; AS269 is conjugated specifically to the non-natural amino acid.

Click to continue reading on OncLive.