News Feature | September 30, 2014

Merck Posts Early Data For Keytruda In Gastric And Bladder Cancer

By Estel Grace Masangkay

Merck reported positive early trial results for its anti-PD-1 therapy pembrolizumab in both advanced gastric cancer and advanced urothelial cancer or bladder cancer.

Pembrolizumab is a humanized monoclonal antibody that works to block PD-1 from interacting with its ligands PD-L1 and PD-L2. Through its mechanism of action, pembrolizumab releases the PD-1 pathway-mediated inhibition of the immune response and triggers an anti-tumor immune response. Pembrolizumab was approved earlier this month under the FDA accelerated approval program as an anti-PD-1 treatment for melanoma. The drug is marketed in the U.S. under the brand name Keytruda.

The ongoing Phase 1B KEYNOTE-012 study is investigating pembrolizumab as monotherapy in patients with advanced head and neck cancer, advanced triple negative breast cancer (TNBC), advanced bladder cancer, and advanced gastric cancer. The treatment demonstrated a 31 percent overall response rate in patients with PD-L1 positive, advanced gastric cancer. The results were observed to be similar in Asian and non-Asian patients, a population which has a high incidence of gastric cancer. “We are encouraged by the signals of anti-tumor activity in advanced gastric cancer, and are eager to move ahead with the Phase 2 study to better understand the potential of pembrolizumab in advanced gastric cancer,” said Dr. Alise Reicin, VP of Oncology at Merck Research Laboratories. Merck said it will start a Phase 2 study for the indication early next year.

In the same study, pembrolizumab as a monotherapy was shown to achieve a 24 percent rate of overall response in patients with PD-L1 positive advanced bladder cancer. “Although at this stage the dataset is small, we are encouraged by the response rate, complete response rate, and the durability of the response in patients suffering from advanced bladder cancer,” said Dr. Reicin. She added that the results will be used to start a Phase 3 study later this year to further study the drug’s potential in the indication.

The results from both trials were presented at the European Society for Medical Oncology (ESMO) 2014 Congress held in Madrid, Spain.

The emerging anti-PD-1 class of immunotherapies, to which pembrolizumab belongs, is forecasted to produce over $30 billion in annual sales by 2025. Pembrolizumab itself is priced at a monthly $12,500 per patient, and is expected to tap into a $140 million market opportunity.