Merck’s Anti-PD1 Therapy Receives Second FDA Approval for Esophageal Carcinoma

On March 23rd, pharma giant Merck announced their anti-PD1 therapy, Keytruda, in combination with platinum- and fluoropyrimidine-based chemotherapy received FDA approval for the treatment of advanced or metastatic esophageal or gastroesophageal junction (GEJ) carcinoma.

Esophageal cancer is the 8th most diagnosed cancer (7th for men, and 13th for women). Although it only accounts for 1% of the newly diagnosed cancers in the US, it is more common in African, and Asian countries. In 2018, Malawi, Mongolia, Kenya, Cape Verde, and China had the highest rates of esophageal worldwide, with around 20 per 100,000.

Currently, there are only two immunotherapies approved for the treatment of esophageal cancer, Opdivo developed by Bristol-Myers Squibb and Keytruda developed by Merck. Both are approved to treat a type of esophageal cancer known as esophageal squamous cell carcinoma. Studies are currently on their way to try to expand their use in other types of esophageal cancer and cement their position as the preferred immunotherapy for esophageal cancer

Blockbuster Drug

Keytruda is a humanized monoclonal antibody that blocks the PD-1 receptor. As a result, it activates the body’s T-lymphocytes, a type of immune cell, which then can detect and fight tumor cells. Currently, over 1,400 trials are studying the efficacy of Keytruda against a wide range of cancers.

Keytruda has been approved, as a single agent or in combination, for the treatment of multiple cancers including melanoma, non-small cell lung carcinoma, head, and neck squamous cell cancer, Hodgkin lymphoma, and others. Not surprisingly, Keytruda is a blockbuster drug for Merck in terms of revenue. The company recently announced that the 2020 worldwide sales of the drug grew 30% to $14.4 Billion.

In 2019, Keytruda was approved for the treatment of a specific type of esophageal cancer, squamous cell cancer, that was positive for PD-L1 expression, one of the ligands for PD-1. The approval differs because it approves Keytruda as a combination therapy for all Advanced or Metastatic Esophageal or Gastroesophageal Junction (GEJ) Carcinoma, regardless of type or PD-L1 expression. This would increase the number of patients eligible to receive Keytruda.

KEYNOTE-590 Trial

The efficacy of Keytruda in combination with platinum- and fluoropyrimidine-based chemotherapy was tested on a multicenter, randomized, placebo-controlled Phase 3 clinical trial. The 749 patients were separated 1:1 ratio, with half of the patients receiving chemotherapy alone, and the other half chemotherapy plus Keytruda. All treatments were administered by intravenous injection. The results are as follows:

• Significantly more patients showed a partial or complete reduction in tumor size with Keytruda plus chemotherapy than with chemotherapy alone (Complete response: 6% vs 2.4%; Partial response: 39% vs 27%).
• Keytruda plus chemotherapy reduced risk of death by 27%.
• Keytruda plus chemotherapy resulted in longer progression-free survival time (Median= 6.3 months) versus chemotherapy alone (Median=5.8 months).
• Most common side effects of Keytruda were nausea, constipation, diarrhea, vomiting, fatigue, decreased appetite, and weight loss.

“There have been few advances in improving survival outcomes in the first-line treatment setting for esophageal cancer over the last three decades,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “We are committed to putting patients first and continuing our research to help advance new approaches to potentially extend the lives of people with cancer. We thank all of the patients, their caregivers, and healthcare professionals who participated in the study.”

Related Article: Novartis’ Acquired Asset from Endocyte Shines in Phase 3 Prostate Cancer Trial

Author

Daniel Ojeda