Antibody Treatment Could Potentially Treat Advanced Gastric Cancer

Patients treated with chemotherapy and IMAB362 had a median overall survival of 16.7 months.

A study presented at the 2016 American Society of Clinical Oncology Annual Meeting found that a new antibody can increase median survival when added to chemotherapy in patients with advanced gastric cancer.

The antibody, IMAB362, targets the protein claudin18.2.

“As claudin18.2 is abundant in gastric tumors, we estimate that half of all patients with advanced gastric cancer may be candidates for this new treatment,” said lead study author Salah-Eddin Al-Batran, MD. “In addition, this unique target is not present in any healthy tissues except the lining of the stomach, thereby minimizing treatment side effects.”

Claudin18.2 is found in pancreatic, lung, esophageal, and ovarian cancers. The protein is involved in making tight junctions that control the flow of molecules between cells in a layer, according to the study.

In tumors, these tight junctions are disrupted and claudin18.2, among other claudin proteins, lose their role, the researchers noted.

When IMAB362 attaches to claudin18.2 on the surface of the cancer cells, an immune response is elicited that kills cancer cells that are coated with the antibody. According to the study, these processes are called antibody‐dependent cell‐mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC).

Included in the study were 161 patients with advanced or recurrent gastric or gastroesophageal junction cancer whose tumors had a specific level of claudin18.2. Patients either received standard chemotherapy comprised of epirubicin, oxaliplatin, and capecitabine, or standard chemotherapy plus IMAB362.

Researchers found that IMAB362 was able to extend the median time to disease progression from 4.8 months to 7.9 months with standard chemotherapy alone.

Patients with the highest levels of claudin18.2 had a median survival of 16.7 months with chemotherapy and IMAB362. For these patients receiving chemotherapy alone, overall survival was 9 months.

Researchers said the treatment was well tolerated and found that vomiting and low blood counts or neutropenia were more common among patients receiving IMAB362. However, severe adverse effects were not increased in the IMAB362 cohort.

Researchers are next planning phase 2 and phase 3 studies to further test IMAB362 in patients with pancreatic cancer.