Gastric cancer is one of the most common gastrointestinal malignancies in the world, and the number of new cases and deaths of gastric cancer in China every year is close to 42% of the world，that bring a heavy disease burden for patients, especially those with advanced or metastatic gastric cancer. Human epidermal growth factor receptor2 (HER2) is overexpressed in about 15-20% of gastric cancer patients, which is associated with tumor aggressiveness and poor prognosis. Therefore, there is a huge unmet clinical need in the treatment of patients with HER2-positive gastric cancer who progress or relapse after first-line therapy. The clinical study of KN026 in this indication has preliminarily shown a breakthrough in efficacy and good safety, which has obvious clinical advantages compared with existing treatment methods.

According to the results of a Phase II clinical trial evaluating the safety and efficacy of KN026 monotherapy in patients with advanced HER2-expressing gastric Cancer or gastroesophageal junction adenocarcinoma who have failed at least one previous standard therapy, published in the European Journal of Cancer in November 2022, a total of 45 subjects received KN026 monotherapy at least once, of which 27 had high HER2 expression, 14 had low HER2 expression, and 4 had no HER2 expression. Among the 39 patients assessed for efficacy, the HER2-high expression group had an objective response rate (ORR) of 56%, median duration of response (DoR) of 9.7 months, median follow-up of 14.7 months, median progression-free survival (mPFS) of 8.3 months, and median overall survival (mOS) of 16.3 months. No drug-related deaths were reported in the study, and the most common grade ≥3 adverse event was gastrointestinal disease (5 patients, 11%). Meanwhile, in 14 patients with high expression of HER who had been previously treated with trastuzumab, the objective response rate (ORR) reached 50%. The above clinical data show that KN026 is significantly effective in treating patients who have failed previous anti-HER2 therapy.

The Phase III clinical trial of KN026 in this indication is in the enrollment phase, and the trial is currently well underway. KN026 has been granted breakthrough treatment designation, and its development and review speed will be further accelerated, which is expected to become the first anti-HER2 treatment for second-line gastric cancer where HER2-targeted therapy has failed.