19 January 2025 – The European Medicines Agency (EMA) has officially approved Jemperli (dostarlimab), GlaxoSmithKline’s (GSK) programmed death-1 (PD-1) checkpoint inhibitor, in combination with chemotherapy as a first-line therapy for patients with advanced or recurrent endometrial cancer.

This marks the first time an immune checkpoint inhibitor has been cleared in Europe for frontline treatment of this disease, positioning Jemperli as a new standard of care in a cancer setting long characterized by limited therapeutic advances.

A Difficult Cancer to Treat

Endometrial cancer is the most common gynecologic malignancy in developed countries, but treatment options for advanced or recurrent disease have historically been scarce. Standard chemotherapy regimens such as carboplatin and paclitaxel remain the backbone of care, but their benefits are often modest, and recurrence rates remain high.

Patients with mismatch repair–deficient (dMMR) tumors have shown higher responsiveness to immunotherapies in late-line settings, but until now, frontline access in Europe was lacking. With Jemperli’s approval, patients can now receive immunotherapy earlier in the treatment pathway, potentially improving outcomes for a broader group of women.

Clinical Data Driving Approval

The EMA’s decision was supported by results from the pivotal RUBY trial, a Phase III study evaluating Jemperli plus standard chemotherapy in patients with advanced or recurrent endometrial cancer. Data showed that the combination significantly improved progression-free survival (PFS) compared with chemotherapy alone, with benefits seen across both dMMR and mismatch repair–proficient (pMMR) populations.

In dMMR patients—the subgroup with the strongest response—risk of disease progression or death was reduced by more than 70% compared to chemotherapy. Importantly, the addition of Jemperli did not introduce unexpected safety signals, and the combination was generally manageable with known PD-1 inhibitor side effects.

These findings reflect a growing oncology trend: pairing immunotherapy with chemotherapy to maximize efficacy while broadening patient eligibility beyond biomarker-defined subsets.

Strategic Implications for GSK and Oncology

For GSK, Jemperli represents one of its flagship oncology products, central to the company’s renewed focus on immuno-oncology. The EMA’s decision strengthens GSK’s commercial and clinical footprint in gynecologic cancers, complementing its existing approvals in late-line endometrial cancer.

More broadly, the approval reinforces the global momentum of checkpoint inhibitors in first-line cancer care. Once reserved for salvage settings, PD-1 and PD-L1 inhibitors are now increasingly moving up the treatment ladder into initial regimens—mirroring similar shifts already seen in lung, bladder, and head-and-neck cancers.

This progression is reshaping how clinical trials are designed, as immunotherapy combinations compete head-to-head against established chemotherapies to redefine standard of care. It also signals regulatory willingness to embrace immunotherapy earlier in treatment paradigms, provided the survival benefit is both statistically significant and clinically meaningful.

Patient and Healthcare Impact

For women facing advanced endometrial cancer, the EMA’s approval of Jemperli plus chemotherapy provides a long-awaited expansion of treatment options. Access to frontline immunotherapy could extend remission periods, improve overall survival prospects, and offer new hope where therapeutic progress has been slow.

On a healthcare systems level, the integration of checkpoint inhibitors into frontline settings may increase treatment costs initially, but advocates argue that improved efficacy and potential for reduced recurrence may offset long-term healthcare burdens. Payers and clinicians will now need to balance immediate budget impact with the promise of meaningful patient outcomes.

Conclusion

The EMA’s approval of Jemperli (dostarlimab) plus chemotherapy as a first-line therapy for advanced endometrial cancer is a landmark moment for both patients and the oncology field. It underscores the expanding reach of immunotherapies into earlier lines of treatment and highlights how combination strategies are rewriting standards of care.

As real-world adoption begins, all eyes will turn to confirmatory data, post-marketing surveillance, and access strategies that will determine how widely patients benefit from this breakthrough. For now, the approval offers a major step forward in addressing a critical unmet need in women’s cancer care.