A Comparative Observational Study Evaluating the Incidence Rate of Endometrial Cancer in Women aged 50 Years and Over Who Use Low dose Vaginal Estrogen Unopposed by a Progestogen: A Post-authorization Safety Study in the United States and Sweden (Low dose vaginal estrogen and endometrial cancer)

Study identification

• EU PAS number:
  EUPAS45602
• Study ID:
  47017
• Official title and acronym:
  A Comparative Observational Study Evaluating the Incidence Rate of Endometrial Cancer in Women aged 50 Years and Over Who Use Low dose Vaginal Estrogen Unopposed by a Progestogen: A Post-authorization Safety Study in the United States and Sweden (Low dose vaginal estrogen and endometrial cancer)
• DARWIN EU® study:
  No
• Study countries:
  Sweden

  United States
• Study description:
  This study is a retrospective cohort study utilizing a longitudinal US healthcare claims data source (HealthCore Integrated Research Database HIRD) and longitudinal data collected from linked Swedish National Registers. The study includes women aged >=50 years with an intact uterus and no prior use of vaginal estrogens. The three exposed treatment groups are new users of unopposed low-dose vaginal estrogen (LDVE), unopposed moderate-dose vaginal estrogen (MDVE), and unopposed high-dose Premarin VC (HDVC) in US only (regardless of other use of prior hormone therapy). The two comparator groups are non-users of vaginal estrogen who are women over age 50 with at least one gynecological visit without prior or current use of vaginal estrogen at the time of the gynecological visit but, regardless of their prior use of hormone therapy, and E+P HT new users with no prior use of hormone therapy. Diagnosis of endometrial cancer will be identified in the US using codes that have been validated in the HIRD, and in Sweden using records in the Swedish Cancer Register. Covariates will include patient demographics, comorbidities, medications, and healthcare utilization. In the primary analysis, adjusted hazard ratios (HRs) will be calculated using Cox proportional hazards models to compare the hazard of endometrial cancer between 1) unopposed LDVE and non users of vaginal estrogen, 2) unopposed MDVE and non-users of vaginal estrogen, 3) unopposed HDVC with non-users of vaginal estrogen (US only).
• Study status:
  Ongoing

Research institutions and networks

Institutions

HealthCore

Carelon Research

Study timelines

Date when funding contract was signed

Planned: 01/03/2019

Actual: 16/09/2019

Study start date

Planned: 01/04/2022

Actual: 01/05/2022

Date of final study report

Planned: 31/10/2023

Sources of funding

Pharmaceutical company and other private sector 

More details on funding

Pfizer

Regulatory

• Was the study required by a regulatory body?:
  Yes
• Is the study required by a Risk Management Plan (RMP)?:
  Not applicable