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Hormonal maintenance therapy in epithelial ovarian cancer

A Randomised Double-blinded Placebo-controlled Phase III Trial of maintenance therapy with aromatase inhibitor in epithelial ovarian cancer patients (MATAO)

Cancer types
Gynaecological cancer
Trial phase


CHF 220 000
ACF funding

Why this trial

The prognosis of patients with advanced epithelial ovarian cancer is poor with a 5-years overall survival rate of 20-30% and a 5-year relapse rate of 75%.

At present, the standard of care after radical surgery and adjuvant chemotherapy is to watch and wait for recurrence. Therefore, additional treatment options, particularly maintenance therapy regimens which might prolong this period of response, are urgently needed.

The MATAO trial will evaluate letrozole, an aromatase inhibitor, in the adjuvant maintenance setting in ovarian cancer patients. The rationale for hormonal treatment is based on the high estrogen receptor expression as predictive marker in this cancer type.

Why this intervention

Research has shown that a high percentage of epithelial ovarian cancers express estrogen receptor, which is an ideal target for hormonal therapy.

Letrozole has been tested and used extensively in estrogen receptor positive breast cancer and is a potent drug tested in several small groups of patients with heavily pretreated ovarian cancer. Letrozole is generally well-tolerated and commonly used in breast cancer patients for over 20 years, and recommended as a treatment option in ovarian cancer.

The goal of this study is to demonstrate that letrozole can be used as maintenance therapy in ovarian cancer.

Trial design

This is a phase 3, international, randomised, two-arm, multi-centric, double-blinded, placebo-controlled superiority trial. 540 patients will be recruited and treated in 20 Swiss, 30 German and 5 Austrian centres.  

Patients with ovarian cancer will be randomly assigned to letrozole or placebo, to determine if letrozole maintenance therapy would improve progression free survival after primary treatment.



  • Prof. Dr. Viola Heinzelmann-Schwarz, University Hospital Basel, Basel, Switzerland (Sponsor-Investigator Int. Project Lead)
  • Prof. Dr. Andreas Du Bois, Kliniken Essen Mitte, Essen, Germany (Deputy International Project Lead)
  • PD Dr. Maximilian Klar, University Hospital Freiburg, Freiburg, Germany (Coordinating Investigator German AGO)
  • PD Dr. Christian Kurzeder, University Hospital Basel, Basel, Switzerland (Coordinating Investigator Swiss GO Trial Group)
  • Prof. Dr. Christian Marth, Tyrolian Clinics, Innsbruck, Austria (Coordinating Investigator AGO-Austria)


  • Swiss GO Trial group, University Hospital Basel, Basel, Switzerland  

Other partners:

  • Helsana Insurance
  • Cancer League Furstentum Liechtenstein
  • Cancer League Switzerland
  • Clinical Trial Unit Basel (CH)
  • AGO ( Arbeitsgemeinschaft Gynäkologische Oncologie) research group (DE)
  • Novartis
  • Roche

Our role

Financial support

Why we support this trial

Intervention has little or no commercial value

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Expected survival benefit

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No major hurdle for clinical implementation

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CHF 220 000
ACF funding

Questions about participation?

Pamela McLaughlin
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Questions about this trial?

Anticancer Fund
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More info: NCT04111978    

Langdon SP, Gourley C, Gabra H, Stanley B. Endocrine therapy in epithelial ovarian cancer. Expert Rev. Anticancer Ther. 2016:1–9.

Bowman A, Gabra H, Langdon SP et al. CA125 Response Is Associated with Estrogen Receptor Expression in a Phase II Trial of Letrozole in Ovarian Cancer : Identification of an Endocrine-sensitive Subgroup CA125 Response Is Associated with Estrogen Receptor Expression in a Phase II Trial of Let. 2002:2233–2239.

Gershenson DM, Bodurka DC, Coleman RL et al. Hormonal Maintenance Therapy for Women With Low-Grade Serous Cancer of the Ovary or Peritoneum. J. Clin. Oncol. 2017; 35(10):1103–1111.  

Paleari L, Gandini S, Provinciali N et al. Clinical benefit and risk of death with endocrine therapy in ovarian cancer: A comprehensive review and meta-analysis. Gynecol. Oncol. 2017; 146(3):504–513.  

Heinzelmann-Schwarz V, Knipprath Mészaros A, Stadlmann S et al. Letrozole may be a valuable maintenance treatment in high-grade serous ovarian cancer patients. Gynecol. Oncol. 2018; 148(1):79–85.

Author: Kristine Beckers (Trial Manager)

Last updated: November2020