SD Announces First Presentation of Data on the Investigational Use of Pembrolizumab in Patients with Advanced Gastric Cancer at ESMO 2014

SD Announces First Presentation of Data on the Investigational Use of Pembrolizumab in Patients with Advanced Gastric Cancer at ESMO 2014

MSD, known as Merck in the United States and Canada, today announced the first presentation of data on the investigational use of pembrolizumab – the company’s anti-PD-1 therapy – in PD-L1 positive, advanced gastric cancer. The early findings presented showed an overall response rate (confirmed and unconfirmed) of 31 percent with pembrolizumab as monotherapy, as measured by investigator assessed, RECIST v1.1 (n= 12/39: 95% CI, 17-47). Similar overall response rates were observed in Asian patients (a population with a high incidence of gastric cancer) and non-Asian patients. At the time of analysis, response durations ranged from 8+ to 20+ weeks with 11 of 12 responders continuing on therapy.

“We are encouraged by the signals of anti-tumour 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.”

These data, from a cohort of the ongoing Phase 1b KEYNOTE-012 study, were presented today, as part of a late-breaking abstract oral session, by Dr. Kei Muro, Aichi Cancer Center Hospital, Nagoya, Japan, at the European Society for Medical Oncology (ESMO) 2014 Congress in Madrid, Spain (ABSTRACT #LBA15). Data investigating the use of pembrolizumab monotherapy in five tumour types will be presented at ESMO 2014.

“MSD is advancing the development of pembrolizumab across different tumour types and lines of therapy,” said Dr. Alise Reicin, vice president, oncology, Merck Research Laboratories. “We are encouraged by the signals of anti-tumour 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.”

Early findings for investigational use of pembrolizumab in advanced gastric cancer

Data from a cohort of the ongoing Phase 1b KEYNOTE-012 study evaluated pembrolizumab monotherapy at 10 mg/kg every two weeks in patients with advanced gastric cancer whose tumours were determined to be positive for PD-L1 expression (n=39). As measured by MSD’s proprietary immunohistochemistry (IHC) clinical trial assay, tumours were classified as PD-L1 positive based on greater than or equal to one percent of tumour cells demonstrating expression of the PD-L1 marker, or any positive staining with the same reagent in tumour stroma. Enrollment was designed to include an equal number of Asian and non-Asian patients. The majority of patients had received two or more prior lines of therapy.

About the KEYNOTE-012 study

KEYNOTE-012 is an ongoing multi-center, non-randomized Phase 1b trial evaluating the safety, tolerability, and anti-tumour activity of pembrolizumab monotherapy in patients with advanced triple negative breast cancer (TNBC), advanced head and neck cancer, advanced urothelial (bladder) cancer, or advanced gastric cancer. The primary endpoints of the study include overall safety, tolerability, and anti-tumour activity (as measured by RECIST v1.1) in PD-L1 positive tumours; secondary endpoints include progression-free survival (PFS), overall survival (OS) and duration of response.

Presentation of additional findings investigating the use of pembrolizumab in advanced non-small cell lung cancer (NSCLC)

Also presented today, were updated findings in patients with treatment-naïve or previously treated advanced non-small cell lung cancer (NSCLC) across cohorts from the ongoing Phase 1b KEYNOTE-001 study (Abstract #LBA43). Data presented in a late-breaking oral session showed anti-tumour activity [overall response rate (ORR)] with pembrolizumab in both treatment-naïve and previously treated patients with advanced NSCLC (n=236) of 26 and 20 percent, respectively, across all doses and schedules assessed as measured by independent central review, RECIST v1.1. Analysis by dose (2 mg/kg every three weeks, 10 mg/kg every three weeks, and 10 mg/kg every two weeks) showed comparable ORR across dosing schedules (33 percent, 21 percent, and 21 percent, respectively).

About pembrolizumab

Pembrolizumab is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2. By binding to the PD-1 receptor and blocking the interaction with the receptor ligands, pembrolizumab releases the PD-1 pathway-mediated inhibition of the immune response, including the anti-tumour immune response.