Pembrolizumab combination results in superior efficacy in ORR in GI cancer
When combined with trastuzumab and chemotherapy, pembrolizumab significantly increased overall response rate in patients with HER2 positive metastatic gastric or gastroesophageal junction cancer, according to data from a phase 3, randomized study of 1L pembrolizumab compared with chemotherapy.
"The first interim analysis of the KEYNOTE 811 study demonstrated a superior efficacy in overall response rate of 74% that resulted in a statistically significant, clinically meaningful improvement and difference of 22.7% when compared to the placebo arm," Yelena Y. Janjigian, MD, a medical oncologist at Memorial Sloan Kettering Cancer Center, said.
In addition, Janjigian and colleagues reported treatment responses were durable and safe.
"The takeaway point is that HER2 is an important biomarker in our disease, and we have a new treatment option for previously untreated patients in combination with pembrolizumab and trastuzumab," Janjigian said.
The researchers enrolled 264 patients whom they randomly divided to receive either pembrolizumab, trastuzumab and chemotherapy, or trastuzumab, chemotherapy and a placebo.
"The overall response rate [in the pembrolizumab arm] was statistically and clinically meaningfully higher, 74% compared with 51% in the placebo arm, with overall response difference of 22.7% with a clinically and statistically significant difference," Janjigian said.
Further, the data demonstrated that response rates were more robust for the pembrolizumab arm, with 32% of patients experiencing a more than 80% decrease in disease burden.
"Median duration of response appears to be also longer with combination therapy, with 70% of patients in the combination arm being on a therapy for at least 6 months or more," Janjigian said.
Adverse events were statistically similar between the two treatment populations, with 80 similar incidents recorded, according to Janjigian.
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Janjigian Y, et al. Abstract 4013. Presented at: ASCO Annual Meeting 2021; June 4-8, 2021 (virtual meeting).
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