A Phase 2/3 interventional study of External Beam Radiation and Niraparib in Endometrial Carcinoma, P53 Mutation and Serous Carcinoma, sponsored by University Health Network, Toronto. Terminated at 1 site in Canada. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-08-12.
Sponsored by University Health Network, Toronto · Phase 2/3, Interventional, and Treatment
This is an umbrella, two-arm, multi-stage, phase II trial. The purpose of the trial in the early stage cohort is to determine if EBRT improves disease free survival (defined as the time from random assignment to disease recurrence or death from any cause) compared to vaginal brachytherapy after chemotherapy in women with serous or p53 aberrant endometrial cancer. The purpose of the trial in the advanced stage cohort is to determine if the maintenance with experimental treatment increases progression free survival, defined as the time from random assignment to disease progression or death from any cause.
SC represents a rare and aggressive histologic subtype of endometrial cancer, associated with a poor prognosis. Moreover, there are marked molecular differences between EC and SC, showing the need to separate clinical trials to develop the personalized treatment paradigms that have improved outcomes in other tumor types, such as breast and lung cancer. Given the absence of consensus between pathologists on the diagnosis of SC, this trial will also incorporate a molecular marker, p53abd.
Several studies have been done in early stage endometrial cancer including diverse histologies, stages and molecular characteristics. Due to the heterogeneity of the patients, there is a lack of knowledge on the best treatment strategy. Even in cases where disease is apparently confined to the endometrium, the rate of recurrence is high. The role of radiation therapy in the management of this disease, with a high propensity for distant failures, remains elusive.
Furthermore, women with endometrial cancer often have multiple comorbidities, needing to optimize the treatment strategies and toxicities. It then results crucial to identify a strategy that is effective and results in limited toxicity.
Advanced or recurrent SC has a poor prognosis. There are no maintenance strategies currently approved for endometrial cancer and this is under investigation.
1,325 studies on the registry are indexed under Endometrial Neoplasms; 447 are open to participants now.
This study's enrollment of 11 is below the median of 70 across 941 interventional studies indexed under Endometrial Neoplasms.
Browse Endometrial Neoplasms studies →University Health Network, Toronto is the lead sponsor of 1,411 studies on the registry; 292 are open to participants now.
Of its 17 completed or terminated interventional studies of FDA-regulated products, 3 (18%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Pelvic EBRT at 45Gy in 25 fractions, in 1.8Gy fractions daily, 5 days per week
Radiation: External Beam Radiation
Vaginal high-dose rate brachytherapy 21 Gy in 3 fractions, prescribed to 5mm (i.e. 100% isodose at 5mm) from the cylinder/applicator surface and top along the upper third to half of the vagina (minimum 3cm, maximum 4cm).
Radiation: Vaginal high-dose rate brachytherapy
Observation
Other: Observation - no drugs
Investigational agent (niraparib), orally, at a dose of 200 mg, or 300 mg, once daily, based on baseline platelet count and weight.
Drug: Niraparib
Radiation therapy given outside the patient to a particular part of the body.
Oral drug
Also known as: Zejula
Internal radiation to the vagina
Observation
Disease Free Survival Rate
Time from random assignment until disease recurrence or death
Time frame: 3 years
Overall Survival Rate
Time from enrollment until death.
Time frame: 5 years
Number Adverse Events Experienced
Time frame: 5 years
Plan to share: No
No publications or documents are linked to this record.
This study is terminated, as verified in Aug 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University Health Network, Toronto