Novel Antibody Drug Conjugate May Provide Survival Benefit in Clinical Trial of HER2-Positive Metastatic Breast Cancer

Patients with HER2-positive metastatic breast cancer treated with the novel antibody drug conjugate ARX788 had a greater progression-free survival benefit compared with those treated with a control, according to findings from an analysis of an ongoing phase 3 study.

Findings from an interim analysis of the phase 3 ACE-Breast-02 trial demonstrated that it met its primary endpoint, meaning the main result that is measured to see if a treatment worked. The primary efficacy endpoint of this trial was progression-free survival (time during and after treatment when the patient lives without disease progression), according to a press release from the drug’s manufacturer, Ambrx Biopharma, and its partner on the trial, NoxoCodex.

After reviewing results of that analysis, ARX788 demonstrated a greater progression-free survival compared to the control group.

“We congratulate our partner, NovoCodex, on this positive phase 3 study. The positive results from this large phase 3 study provide further support for our rationale to develop ARX788 globally in HER2-positive breast cancer patients," said Daniel O’Connor, chief executive officer of Ambrx, in the release.

Researchers conducting the randomized phase 3 clinical trial are evaluating the anti-HER2 monoclonal antibody conjugate ARX788 in patients with HER2-positive breast cancer that has either locally advanced (spread to nearby tissue or lymph nodes) or metastasized (spread from one part of the body to another).

The trial includes 441 patients with HER2-positive breast cancer who were previously treated with taxane and Herceptin (trastuzumab), according to the release. These patients were randomly assigned either ARX788 or Tykerb (lapatinib) combined with Xeloda (capecitabine), known as the control group.

ARX788 is also currently being studied in gastric cancer, gastroesophageal junction adenocarcinoma (a rare cancer type of the esophagus) and other solid tumors, according to the release. The U.S. Food and Drug Administration has previously granted ARX788 fast track designation for patients with HER2-positive metastatic breast cancer and orphan drug designation for gastric cancer.

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