Merck Reports Results Of KEYTRUDA In Patients With Advanced Stomach Cancer

(RTTNews) - Merck (MRK) announced clinical results on the investigational use of KEYTRUDA in PD-L1 positive, advanced stomach cancer.

The early findings presented showed an overall response rate of 31 percent with KEYTRUDA as monotherapy. In a small Phase I study involving 39 patients with PD-L1 positive, advanced stomach cancer, a total of 12 people showed tumor shrinkage after being given Keytruda.

Almost, same kind of overall response rates were observed in Asian patients and non-Asian patients. At the time of analysis, response durations ranged from more than 8 to 20 weeks with 11 of 12 responders continuing on therapy.

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

The company said that the adverse events were consistent with previously reported safety data for KEYTRUDA. The most common investigator-assessed, treatment-related adverse events included hypothyroidism and fatigue. Grade 3-5 investigator-assessed, treatment-related adverse events occurred in a total of three patients, with one patient each in peripheral sensory neuropathy, hypoxia and pneumonitis. No infusion-related reactions were observed and no patients discontinued KEYTRUDA due to a treatment-related adverse reaction. One treatment-related death due to hypoxia, as assessed by the investigator, was reported.

KEYTRUDA or 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, KEYTRUDA releases the PD-1 pathway-mediated inhibition of the immune response, including the anti-tumor immune response.

Gastric cancer, also called stomach cancer, is a type of cancer that begins in the stomach. Most gastric cancers are adenocarcinomas, which develop from the cells of the innermost lining (mucosa) of the stomach. More than 70 percent of gastric cancer cases occur in developing countries, with half of all cases occurring in Eastern Asia.

Merck said it plans to start a Phase II study in the first quarter of 2015 on the back of the positive results.