Positive results from the primary analysis of the DUO-E Phase III trial showed that Imfinzi (durvalumab) plus platinum-based chemotherapy, followed by either Imfinzi monotherapy or Imfinzi plus Lynparza (olaparib), both demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared to chemotherapy alone in the overall trial population of patients with newly diagnosed advanced or recurrent endometrial cancer.
These results will be presented today in a proffered paper session at the 2023 European Society for Medical Oncology (ESMO) Congress in Madrid, Spain (Presentation #LBA41) and simultaneously published online in the Journal of Clinical Oncology.
In the overall trial population, results showed that treatment with Imfinzi plus chemotherapy followed by Imfinzi plus Lynparza (Imfinzi plus Lynparza Arm) and treatment with Imfinzi plus chemotherapy followed by Imfinzi monotherapy (Imfinzi Arm) demonstrated a reduction in the risk of disease progression or death, by 45% (hazard ratio [HR] 0.55; 95% confidence interval [CI] 0.43-0.69; pp=0.003), respectively, versus chemotherapy alone (Control Arm). Median PFS was 15.1 months in the Imfinzi plus Lynparza Arm and 9.6 months in the Control Arm.
Mismatch repair (MMR) status is a biomarker of interest in endometrial cancer, therefore a prespecified exploratory subgroup analysis by MMR status was conducted in DUO-E. Results from the analysis of mismatch repair proficient (pMMR) patients showed a reduction in the risk of disease progression or death in both the Imfinzi plus Lynparza and the Imfinzi Arms, by 43% (HR 0.57; 95% CI 0.44-0.73) and 23% (HR 0.77; 95% CI 0.60-0.97), respectively, versus the Control Arm. Median PFS was 15 months in the Imfinzi plus Lynparza Arm and 9.7 months in the Control Arm.
Results from the analysis of mismatch repair deficient (dMMR) patients showed a similar reduction in the risk of disease progression or death in both the Imfinzi plus Lynparza and the Imfinzi Arms, by 59% (HR 0.41; 95% CI 0.21-0.75) and 58% (HR 0.42; 95% CI 0.22-0.80), respectively, versus the Control Arm.
Interim overall survival (OS) data showed a favourable trend for both treatment regimens in the overall population.
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, “These findings showcase, for the first time, the potential of combining immunotherapy with a PARP inhibitor to deliver significant clinical improvements for these patients. These DUO-E data may offer oncologists novel avenues to enhance outcomes for endometrial cancer patients.”
Susan Galbraith, Executive Vice President, Oncology R&D, AstraZeneca, said, “The treatment options for most patients with advanced endometrial cancer are limited, especially for those with mismatch repair proficiency, and have not changed for many years. We are delighted that these DUO-E data show meaningful clinical improvements for patients when Imfinzi and Lynparza are combined or when Imfinzi is added alone. We look forward to discussing these data with global regulatory authorities and bringing these important new treatment approaches to patients as soon as possible.”
PD-L1 is a known biomarker for Imfinzi in other indications and a prespecified analysis based on PD-L1 status showed, in the PD-L1 positive population, that treatment reduced the risk of disease progression or death by 58% (HR 0.42; 95% CI 0.31-0.57) and 37% (HR 0.63; 95% CI 0.48-0.83) in the Imfinzi plus Lynparza and the Imfinzi Arms, respectively, versus the Control Arm. Median PFS was 20.8 months in the Imfinzi plus Lynparza Arm and 9.5 months in the Control Arm.
In the PD-L1 negative population, treatment reduced the risk of disease progression or death by 20% (HR 0.80; 95% CI 0.55-1.16) and 11% (HR 0.89; 95% CI 0.59-1.34) in the Imfinzi plus Lynparza and the Imfinzi Arms, respectively, versus the Control Arm.
The safety and tolerability profiles of both regimens (Imfinzi plus Lynparza Arm and Imfinzi Arm) were broadly consistent with those observed in prior clinical trials and the known profiles of the individual medicines.1,2
The most common adverse events (AEs) (affecting 20% or more of patients) reported in the Imfinzi plus Lynparza Arm during the overall study were anaemia (62%), nausea (55%), fatigue and asthenia (54%), alopecia (51%), neutropenia (42%), constipation (33%), thrombo-cytopenia (30%), diarrhoea (28%), vomiting (26%), peripheral neuropathy (25%), peripheral sensory neuropathy (25%), arthralgia (24%), decreased appetite (23%), leukopenia (20%) and urinary tract infection (20%).
The most common AEs reported in the Imfinzi Arm during the overall study were alopecia (50%), anaemia (48%), fatigue and asthenia (43%), nausea (41%), neutropenia (36%), diarrhoea (31%), arthralgia (30%), thrombo-cytopenia (28%), constipation (27%), peripheral neuropathy (26%), peripheral sensory neuropathy (26%) and vomiting (21%).
Notes
Endometrial cancer
Endometrial cancer is a highly heterogeneous disease that originates in the tissue lining of the uterus and is most common in women who have already been through the menopause, with the average age at diagnosis being over 60 years old.3-5 It is the 6th most common cancer in women worldwide.6 Incidence and mortality of endometrial cancer are expected to increase by approximately 46% and 62% respectively (from 417,400 cases and 97,400 deaths in 2020 to 608,130 cases and 157,813 deaths) in 2040.6,7
The majority of patients with endometrial cancer are diagnosed at an early stage of disease where the cancer is confined to the uterus. They are typically treated with surgery and/or radiation and the 5-year survival rate is high (approximately 95%). Patients with advanced disease (Stage III-IV) usually have a much poorer prognosis, with the 5-year survival rate falling to around 20-30%. The standard of care for advanced endometrial cancer has traditionally been limited to chemotherapy.5,8,9,10,11,12 There is a high unmet need for novel treatment options and strategies that can improve long-term outcomes in advanced or recurring endometrial cancer.10,13
DUO-E
The DUO-E trial (GOG 3041/ENGOT-EN10) is a three-arm, randomised, double-blind, placebo-controlled, multicentre Phase III trial of 1st-line Imfinzi (durvalumab) plus platinum-based chemotherapy (carboplatin and paclitaxel) followed by either Imfinzi monotherapy or Imfinzi plus Lynparza (olaparib) as maintenance therapy versus platinum-based chemotherapy alone as a treatment for patients with newly diagnosed advanced or recurrent endometrial cancer.
The DUO-E trial randomised 699 patients with newly diagnosed advanced or recurrent epithelial endometrial carcinoma to receive either Imfinzi (1120mg) or placebo, given every three weeks in addition to standard-of-care platinum-based chemotherapy. After 4-6 cycles of chemotherapy, patients (whose disease had not progressed) then received either Imfinzi (1500mg) or placebo every four weeks as maintenance, plus 300mg Lynparza (300mg BID [2x150mg tablets, twice a day]) or placebo until disease progression.
The dual primary endpoint was progression-free survival (PFS) of each treatment arm versus standard of care. Key secondary endpoints included overall survival (OS), safety and tolerability. Mismatch repair status, recurrence status and geographic location were stratification factors. Mismatch repair deficient (dMMR) status reflects an inability to correct DNA replication errors and therefore results in an increased risk of cancer, while mismatch repair proficient (pMMR) status indicates when DNA repair pathways remain intact and where the mismatch repair pathway is active and functional.14,15 The trial was sponsored independently by AstraZeneca and conducted in 253 study locations across 22 countries including the US, Europe, South America and Asia.
