Combination Osilodrostat and Cabergoline in Cushing's Disease (COSCA-ECD)

May 15, 2026 updated by: Haider Ayad Alidrisi, University of Basrah

Combination Osilodrostat and Cabergoline Versus Osilodrostat Alone in Cushing's Disease in Iraq: Assessment of Efficacy and Safety

Cushing disease remains a challenging endocrine disorder in which persistent or recurrent hypercortisolism often requires medical therapy after surgery or when surgery is not feasible. Combination medical therapy has emerged as a rational strategy to improve biochemical control through complementary mechanisms while potentially reducing treatment escape and dose-related toxicity. Cabergoline exerts pituitary D2-receptor-mediated inhibition of ACTH secretion and may provide partial cortisol control in selected patients, although treatment escape and variable durability remain important limitations. Osilodrostat is a potent 11β-hydroxylase inhibitor that produces rapid and often substantial reductions in cortisol secretion, with clinical improvement in metabolic and cardiovascular features of hypercortisolism. The osilodrostat-cabergoline combination is mechanistically attractive because it pairs central ACTH suppression with peripheral blockade of cortisol synthesis, but published evidence remains limited to small real-world experiences and does not yet define optimal sequencing, dosing, or long-term benefit. Safety considerations include adrenal insufficiency from overtreatment, osilodrostat-associated hypertension from mineralocorticoid precursor accumulation, and hyperandrogenism due to steroid precursor shunting.

Combination medical therapy in Cushing disease is a promising individualized approach, and the osilodrostat-cabergoline pairing is biologically plausible and potentially effective, but current literature is insufficient to support firm recommendations regarding efficacy, safety, or patient selection.

The study aims to evaluate whether a combination can result in rapid, more control of Cushing's disease (clinically and biochemically)? Can cabergoline reduces Osilodrostat dose requirement, reduces Osilodrostat related mineralocorticoid and hyperandrogenism side effects?

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

In this study, adult patients with active CD (with or without previous TSS or radiotherapy) will be enrolled. Investigators will start treatment for all with Osilodrostat using up-titrating doses on bi-weekly bases. Then the patients will be randomized into two groups. For the first group, carbergoline with escalating doses will be added. For the second group, the patients will continue osilodrostat treatment with increasing doses. Through the period of the study interventions, the patients will be followed clinically, and biochemical looking for treatment related efficacy and safety.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Iraq
      • Basra, Iraq, 61001
        • Faiha Specialized Diabetes, Endocrine, and Metabolism Center
      • Karbala, Iraq
        • Al-Hassan Metabolism Endocrine and Diabetes Center
      • Mosul, Iraq
        • Al-Waffa Specialized Center for Diabetes and Endocrinology
      • Najaf, Iraq
        • Najaf Specialized Diabetes and Endocrine Center
      • Nasiriyah, Iraq
        • Thi-Qar Specialized Diabetes, Endocrine and Metabolism Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Cushing's disease: Not treated or received treatment (TSS and/or radio surgery). And
  • Active disease confirmed with repeated two biochemical tests (1-mg overnight dexamethasone suppression test and late night salivary cortisol), And
  • Inappropriate ACTH elevation, And
  • Positive ACTH response to desmopressin stimulation test, And
  • MRI finding of pituitary adenoma.

Exclusion Criteria:

  • Severe hepatic impairment (Child-Pugh C).
  • Pregnancy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Osilodrostat alone
Osilodrostat up to 15 mg daily
Drug: osilodrostat
1 mg (pill) twice daily for two weeks, titrated to 2.5 mg (5 mg pill divided) twice daily for two weeks, then 7.5 (half 5 mg pill and 5 mg pill) for four weeks, then 10 mg (5 mg pill twice daily) for four weeks, then 15 mg (5 mg pill thrice daily).
Active Comparator: Combination osilodrostat and cabergoline
Osilodrostat up to 5 mg daily plus Cabergoline up to 3 mg weekly
Drug: osilodrostat and cabergoline
1 mg (pill) twice daily for two weeks, titrated to 2.5 mg (5 mg pill divided) twice daily for two weeks, then Add: Cabergoline 0.5 mg twice weekly for four weeks, titrated to 1 mg twice weekly for four weeks, then 1 mg thrice weekly.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in serum cortisol
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, 48 weeks.
serum cortisol (8-9 am and 6-7 pm).
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, 48 weeks.
Number of patients achieved serum cortisol (7-12 Mg/dL)
Time Frame: 4 weeks, 8 weeks, 12 weeks, 24, weeks, 36 weeks, and 48 weeks.
measurement of 8-9 am serum cortisol.
4 weeks, 8 weeks, 12 weeks, 24, weeks, 36 weeks, and 48 weeks.
Changes in Cushing 's Quality-of-Life questionnaire 12-items (CushingQoL) score for the patients quality of life.
Time Frame: At 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Changes in CushingQoL (12 items) questionnaire. The lowest score is 12 and highest score is 60. The highest the score, the better life quality and clinical improvement in Cushing syndrome.
At 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in the patients' Body weight (kg)
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
measurement of the patients' body weight using scale in the early morning and fasting, bare feet, light clothes, using electronic scale.
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Changes in the patients' Blood pressure (increase or decrease) and increase or decrease requirements for blood pressure lowering medications.
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Measurement of the patients' blood pressure (SBP/DBP mmHg) using standard electronic arm cuff blood pressure machine.
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Changes in HbA1c (%)
Time Frame: At 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
measurement of the patients HbA1c % using BioRad D10
At 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Assessment of clinical hyperandrogenic features (acne and hirsutism), whether increase or decrease for female patients
Time Frame: At 12 weeks, 24 weeks, 36 weeks, and 48 weeks.

Acne will be assessed by clinical examination and reported as improved or increased.

Hirsutism will be assessed using the changes in the modified Ferrimann-Gallwey (mFG) score (0 - 36), the highest the score, the more severe hirsutism.
At 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Changes in plasma ACTH
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
measurement of early morning plasma ACTH (pg/ml)
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Changes in serum dehydroepiandrosterone acetate (Mg/dl)
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
measurement of serum dehydroepiandrosterone acetate (Mg/dl)
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Changes in the corrected QT interval on electrocardiograph (ECG).
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Performance of ECG for assessment and record of the c QT interval.
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Changes in serum potassium
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
measurement of serum potassium
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Development of symptoms of hypoadrenalism
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Development of symptoms of hypoadrenalism in the form of (anorexia, nausea, vomiting, fatigue, abdominal pain, dizziness, and hypotension)
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Number of patients will have morning serum cortisol less than (5 Mg/dl)
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
measurement of serum cortisol in the morning and fasting state.
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Other drug related side effects
Time Frame: At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.
Side effects of Osilodrostat and cabergoline
At 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 48 weeks.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Basrah

Investigators

  • Principal Investigator: Haider A Alidrisi, Univeristy of basrah, Faiha Specialized Diabetes, Endocrine, and Metabolism Center
  • Principal Investigator: Ibrahim H Hussein, MD, Univeristy of basrah, Faiha Specialized Diabetes, Endocrine, and Metabolism Center
  • Study Chair: Abbas A Mansour, Univeristy of basrah, Faiha Specialized Diabetes, Endocrine, and Metabolism Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 11, 2026

Primary Completion (Estimated)

June 1, 2028

Study Completion (Estimated)

August 1, 2028

Study Registration Dates

First Submitted

May 11, 2026

First Submitted That Met QC Criteria

May 15, 2026

First Posted (Actual)

May 22, 2026

Study Record Updates

Last Update Posted (Actual)

May 22, 2026

Last Update Submitted That Met QC Criteria

May 15, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 05/13/26

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Only IPD used in the results publication.

IPD Sharing Time Frame

Beginning 3 months and ending 3 years after the publication of results.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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