The US Food and Drug Administration (FDA) grants orphan drug designation to Ambrx for ARX788, a homogeneous and highly stable antibody drug conjugate, for the treatment of HER2-positive gastric cancer.

The Office of Orphan Drug Products of the FDA grants such orphan status to aid the development of medicines for underprivileged patients, or rare disorders, affecting less than 200,000 people in the US.

With the orphan drug designation for ARX788 to treat patients with gastric cancer and cancer at the gastroesophageal junction, biopharmaceutical company Ambrx – which creates engineered precision biologics with the aid of an expanded genetic code – gets to enjoy benefits such as exemption towards tax credits for qualified clinical trials and FDA prescription drug user fees.

The designation also makes Ambrx eligible for 7 years of market exclusivity to an orphan drug post-approval, after Ambrx receives a marketing approval from the FDA.

By end of 2021, Ambrx expects the release of additional Phase 1 data from the ACE-Gastric-01 trial and initiation of ACE-Gastric-02, a global Phase 3 trial for HER2-positive gastric cancer, during the second half of 2021.

ACE-Gastric-02 is presently designed to be a randomised trial of ARX788 versus the physician’s choice of treatment in second line HER2-positive gastric cancer as well as HER2-positive cancer at the gastroesophageal junction.

Ambrx president and CEO Feng Tian said: “The ongoing Phase 1 ACE-Gastric-01 trial has shown promising anti-tumour activity in HER2-positive advanced gastric patients who have been previously treated with trastuzumab and chemotherapy in the metastatic setting. Receiving orphan drug designation from the FDA is an important milestone in our ongoing efforts to develop ARX788 for a wide range of HER2-positive cancers. We are proud to be targeting a rare disease that is currently severely underserved by advancing ARX788 into additional clinical trials.”