Adding Keytruda to Standard Chemo Improves Outcomes in Advanced Endometrial Cancer

The phase 3 NRG-GY018 trial met its main goal of improved progression-free survival (time from treatment until disease worsens) with Keytruda (pembrolizumab) plus standard of care chemotherapy in patients with stage 3 or 4 or recurrent endometrial cancer, according to an announcement from Merck, the manufacturer of Keytruda.

Keytruda bested chemotherapy alone in this patient population, regardless of their mismatch repair deficient status, a biomarker that — among other things — has been associated with promising responses to immunotherapy agents such as Keytruda.

“Patients with advanced stage or recurrent endometrial cancer, the most common type of gynecologic cancer in the U.S., face a poor prognosis with limited treatment options. This is particularly notable in patients who progress after prior platinum-based adjuvant therapy with disease not amenable to curative surgery or radiation,” said Dr. Ramez Eskander, principal investigator and gynecologic oncologist at the University of California, San Diego.

NRG-GY018 is a randomized, placebo-controlled (meaning that some patients got standard of care plus placebo, while the others got standard of care plus Keytruda) phase 3 trial that included 819 patients with stage 3, 4A or 4B or recurrent endometrial cancer (disease that has come back and spread from the uterus beyond the pelvis). Patients were randomly assigned to either the placebo or Keytruda groups with all receiving standard chemotherapy (paclitaxel and carboplatin).

Of note, patients also had their mismatch repair status tested before the start of the trial; 70% were mismatch repair proficient, whereas 30% were mismatch repair deficient, meaning that a majority of patients had a genetic mutation that makes it more difficult for mistakes from DNA replication to be repaired. As such, these patients tend to have more genetic mutations, which could lead to cancer.

The main goal of the trial was progression-free survival, but secondary endpoints that the researchers were also considering were overall survival (time from treatment until death of any cause), objective response rate (the percentage of patients whose cancer shrinks as a result of treatment), duration of response and safety.

“In this study, (Keytruda) in combination with carboplatin and paclitaxel resulted in a statistically significant and clinically meaningful improvement in progression-free survival in both the (mismatch repair deficient) and (mismatch repair proficient) study populations.”

Eskander noted that findings from the study will be presented at an upcoming oncology meeting.

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