Promising Combination Therapy for Endometrial Cancer Shows Extended Survival Rates

Introduction to Endometrial Cancer

Endometrial cancer is a common type of cancer that starts in the lining of the uterus. It primarily affects women who have gone through menopause, though it can occur at any age. Early detection can often lead to effective treatment, but advanced cases require more intensive approaches.

This article will focus on the latest findings related to the combination of pembrolizumab and chemotherapy in treating endometrial cancer.

Understanding Pembrolizumab

Pembrolizumab, also known by the brand name Keytruda, is an immunotherapy drug that helps the immune system fight cancer cells. It works by blocking a protein called PD-1, effectively unleashing the immune system to attack tumors more effectively.

Often used in combination with other treatments, pembrolizumab has shown promising results in various types of cancer, including lung, kidney, and now, endometrial cancer.

The NRG-GY018 Trial

The phase 3 NRG-GY018 trial was conducted to evaluate the effectiveness of pembrolizumab combined with chemotherapy in treating endometrial cancer. The trial included a total of 810 patients who were randomly divided into two groups: one receiving the combination treatment and the other receiving a placebo along with chemotherapy.

The trial was presented at the 2024 Society of Gynecologic Oncology Annual Meeting on Women’s Cancer, highlighting significant findings particularly in overall survival (OS) and progression-free survival (PFS).

Key Results for Overall Survival

In patients with mismatch repair proficient (pMMR) status, the median overall survival was slightly better in the pembrolizumab arm compared to the placebo arm—27.96 months vs. 27.37 months, respectively. Although the data were not statistically significant, the trend suggests a potential benefit in OS for patients receiving the combination therapy.

For patients with mismatch repair deficient (dMMR) status, the median OS was not reached in either group, indicating a possible more extended survival benefit for those receiving pembrolizumab in combination with chemotherapy.

Progression-Free Survival Benefits

The results were more pronounced when looking at progression-free survival (PFS). For patients with pMMR status, the median PFS was 13.1 months in the pembrolizumab arm compared to 8.7 months in the placebo arm, showing a significant improvement.

For those with dMMR status, PFS was not reached in the pembrolizumab arm, compared to 8.3 months in the placebo arm—an even more striking result indicating the potential of the combination therapy to delay disease progression substantially.

Impact of PD-L1 Status

The study further evaluated the impact of PD-L1 status. Patients with a PD-L1 combined positive score (CPS) of 1 or more showed better PFS in the pembrolizumab arm across both pMMR and dMMR groups. This suggests that PD-L1 status could be a useful biomarker to identify patients who may benefit most from pembrolizumab treatment.

In the pMMR group, patients with PD-L1 CPS of 1 or more had a median PFS of 13.1 months in the pembrolizumab arm versus 8.5 months in the placebo arm. In the dMMR group with the same PD-L1 score, PFS was not reached in the pembrolizumab arm compared to 8.3 months in the placebo arm.

Conclusion

The findings of the NRG-GY018 trial support the addition of pembrolizumab to chemotherapy for first-line treatment in patients with advanced or recurrent endometrial cancer. These results are promising, particularly for patients with dMMR status, suggesting significant benefits in extending both overall and progression-free survival.

While pembrolizumab plus chemotherapy is not yet an approved regimen for this indication in the United States, ongoing trials and further data may lead to expanded treatment options for endometrial cancer patients in the future.