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NCT Number: NCT07436793

Progestins for the Treatment of Endometrial Cancer or Precancers of the Uterus Before Surgery, The Pro-Window Trial

This phase II trial tests compares the effect of progestins, megestrol acetate to micronized progesterone, in treating patients with endometrial cancer and precancers of the uterus (atypical endometrial hyperplasia) before surgery. Progestins, similar to the natural hormone progesterone, are approved drugs used in birth control and hormone replacement pills, and some can treat uterine endometrial cancers. In the initial comparison of this rotating umbrella trial, megestrol acetate, a progestin, will be compared to micronized progesterone, a form of natural progesterone that is a hormone produced by body normally. Hormone therapy using megestrol acetate and micronized progesterone may be effective in treating patients with endometrial cancer or atypical endometrial hyperplasia before surgery, and understanding the tissue effects of each agent on the malignant endometrium will uncover novel mechanistic and biomarker data to understand how best to advanced hormone therapy for endometrial cancer.

Recruiting

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Key information

Age range

18 year and older

Sex eligibility

Female

Study type

Interventional

Phase

Phase 2

Primary location

University of Iowa/Holden Comprehensive Cancer Center, Iowa City, Iowa, United States

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About this study

PRIMARY OBJECTIVES:

I. Perform an adaptive, master protocol, surgical window of opportunity rotating umbrella trial to assess the effectiveness of progestins in tissues from women with newly diagnosed endometrial cancer or atypical endometrial hyperplasia.

II. Establish biomarkers and molecular signatures of progestin efficacy in patients with endometrial cancer.

OUTLINE: Patients are randomized to 1 of 2 arms in the initial comparison.

ARM I: Patients undergo biopsy or curettage and then receive megestrol acetate orally (PO) twice daily (BID) 21-24 days prior to standard of care (SOC) hysterectomy on study.

ARM II: Patients undergo biopsy or curettage and then receive micronized progesterone PO once daily (QD) beginning 21-24 days prior to SOC hysterectomy on study.

After completion of study treatment, patients are followed up at 30-45 days after surgery.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients must have a histologically proven diagnosis of endometrioid endometrial adenocarcinoma by endometrial curettage or biopsy within 8 weeks prior to registration. Pathology reports should document adequate tissue from the biopsy and slides should be reasonable determined to be obtainable by the study team for study use
  • History/physical examination within 42 +/- 5 days of planned surgical procedure (18-21 days from day 1)
  • Age ≥ 18
  • The trial is open only to women with primary endometrioid adenocarcinoma of the uterine corpus (all histologic grades and stages) who are planned and appropriate for primary surgical treatment to include removal of the uterine corpus via any surgical modality. The patient must be considered a suitable surgical candidate
  • Patients must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, 2, or 3 within 28 days prior to registration
  • Formalin-fixed, paraffin-embedded tumor tissue from the biopsy or curettage must be reasonably deemed available for submission along with the corresponding pathology report
  • Platelets ≥ 100,000/μl
  • Granulocytes (absolute neutrophil count [ANC]) ≥ 1,500/μl
  • Creatinine ≤ 1.6 mg/dl
  • Serum glutamic-pyruvic transaminase (SGPT) (alanine transaminase [ALT]) ≤ 3 x upper limits of normal
  • Bilirubin within institutional normal limits
  • The patient must provide study-specific informed consent and authorization permitting release of personal health information prior to study entry
  • Any patients of childbearing potential must have a negative pregnancy test

Exclusion criteria

  • Patients with any non-endometrioid histology (such as serous, clear cell, or carcinosarcoma or mixed)
  • Patients who have received prior progestin or anti-estrogen therapy during the 3 months before the diagnosis of endometrioid adenocarcinoma of the uterine corpus is established. Estrogen therapy alone is allowed
  • Patients with ECOG performance status of 4
  • Patients with history of deep venous thrombosis or pulmonary embolism within the past 2 years or ongoing thromboembolic disorders
  • Patients who have previously received systemic, radiation or other treatment for uterine cancer
  • Patients for whom formalin-fixed, paraffin-embedded tumor tissue from the biopsy or curettage is scant or unavailable
  • Patients with a suspected or known peanut allergy
  • Patients with serious comorbidities or gastrointestinal obstruction that precludes taking oral medications or have malabsorptive disease

Treatment and study plan

Biopsy Procedure

Procedure

Undergo biopsy

Other names: Biopsy, BIOPSY_TYPE, Bx

Curettage Procedure

Procedure

Undergo curettage

Other names: Curettage

Hysterectomy

Procedure

Undergo hysterectomy

Other names: Hysterectomy NOS, hysterectomy type, hysterectomy_type

Megestrol acetate

Drug

Given PO

Other names: 17-Hydroxy-6-methylpregna-4,6-diene-3,20-dione acetate, 17.alpha.-Acetoxy-6-methylpregna-4,6-diene-3,20-dione, 6-Dehydro-6-methyl-17.alpha.-acetoxyprogesterone, 6-Methyl-6-dehydro-17.alpha.-acetoxyprogesterone, BDH 1298, BDH-1298, Maygace, Megace, Megestat, Megestil, Niagestin, Ovaban, Pallace, SC 10363, SC-10363

Progesterone Only Hormone Replacement Therapy

Drug

Given PO

Other names: Progesterone only

Primary outcomes

  1. Tissue response to progestin therapy

    Time frame: From the time of pre treatment diagnostic biopsy to the time of post treatment hysterectomy specimen

    Will be determined by a change in the percentage in the expression of the proliferative marker Ki-67 comparing the pretreatment diagnostic biopsy to the posttreatment hysterectomy specimen. Immunohistochemical evaluation of Ki-67 protein expression will be determined as a continuous variable using the percent of cells staining positive in the nucleus

Sponsors and collaborators

Lead sponsor

New Mexico Cancer Research Alliance

Other

Collaborators

  • National Cancer Institute (NCI)
  • University of New Mexico Cancer Center

Registry information

Official study title

Evaluating Promising Progestins in Endometrial Cancer Through a Rotating Umbrella Surgical Window Trial - The PRO-WINDOW TRIAL for Endometrial Cancer

Important dates

Study start
2026
Primary completion
2030
Study completion
2031
First posted
Feb 27, 2026
Registry last updated
Jul 2, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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