Imfinzi plus chemotherapy approved in the US for mismatch repair deficient advanced or recurrent endometrial cancer

AstraZeneca’s Imfinzi (durvalumab) in combination with carboplatin and paclitaxel followed by Imfinzi monotherapy has been approved in the US as treatment for adult patients with primary advanced or recurrent endometrial cancer that is mismatch repair deficient (dMMR).

The approval by the Food and Drug Administration (FDA) was based on the results of a prespecified exploratory subgroup analysis by MMR status in the DUO-E Phase III trial. Results from DUO-E were published in the Journal of Clinical Oncology.

In the trial, Imfinzi plus carboplatin and paclitaxel followed by Imfinzi monotherapy (Imfinzi arm) reduced the risk of disease progression or death by 58% in patients with dMMR endometrial cancer versus chemotherapy alone (hazard ratio 0.42; 95% confidence interval 0.22-0.80).

In the US, endometrial cancer is the fourth most common cancer in women, with more than 66,000 patients diagnosed and almost 12,000 deaths in 2022. Patients diagnosed at an early stage of disease have a five-year survival rate of approximately 80-90%, but there is a significant need for new treatment options for people with advanced disease, where the survival rate falls to less than 20%.

Shannon N. Westin, Professor of Gynecologic Oncology and Reproductive Medicine at The University of Texas MD Anderson Cancer Center, and principal investigator of the trial, said, “With the incidence and mortality of endometrial cancer expected to continue to increase significantly in the coming decades, it is more important than ever that we bring new treatment options to patients at the earliest possible moment in their care. This approval underlines clear evidence that durvalumab plus chemotherapy followed by durvalumab monotherapy delivers important clinical benefits for patients with mismatch repair deficient endometrial cancer.”

Dave Fredrickson, Executive Vice President, Oncology Business Unit, AstraZeneca, said: “There have been limited advances in the treatment of endometrial cancer in the last few decades, and continued innovation is critical as the burden of this cancer is expected to grow in the future. Immunotherapy in combination with chemotherapy is emerging as a new standard of care in this setting, and the approval of Imfinzi offers an important new option for patients with mismatch repair deficient disease.”

The safety and tolerability profile of the Imfinzi and chemotherapy regimen was generally manageable, well tolerated and broadly consistent with prior clinical trials with no new safety signals.

The Lynparza (olaparib) and Imfinzi arm, which investigated Imfinzi plus chemotherapy followed by Imfinzi plus Lynparza as maintenance therapy, also met the primary endpoint of progression-free survival (PFS). The trial continues to assess OS as a key secondary endpoint for both arms. Regulatory applications for both Imfinzi as well as Imfinzi and Lynparza regimens are currently under review in the EU, Japan and several other countries based on the DUO-E results.