Safety and Potency of a High Cabergoline Dosage in Microprolactinomas
University of Sao Paulo General Hospital
70 participants
Mar 4, 2026
INTERVENTIONAL
Conditions
Summary
This will be a multicenter, prospective, randomized, open-label trial with women harboring microprolactinomas and treatment naïve. The sample will be added consecutively and randomized into 2 unblinded groups: the high dosage group will receive a high cabergoline (CAB) dose for a period of \~6 months vs the standard dosage group, which will use the lowest needed dose of CAB to achieve normoprolactinemia for 2 years. The primary outcome will be remission rate.
Eligibility
Inclusion Criteria15
- \. Willing and able to provide written informed consent prior to any study-related procedures
- \. Adults \>18 years old
- \. Pre-menopausal women
- \. Presence of signs and symptoms matching prolactinoma
- \. Hyperprolactinemia, defined as a prolactin (PRL) level ≥2 times the local laboratory maximum level of normality, present at the time of enrolment
- \. Presence of an identifiable pituitary mass on MRI with a maximum diameter of less than 1cm, independently of Knosp/invasiveness of the cavernous sinus
- \. Treatment naïve
- \. Females who engage in heterosexual intercourse must agree to use either a highly effective or a clinically acceptable method of contraception from the beginning of screening to the last study visit, which will include:
- Hysterectomy or bilateral salpingectomy
- Bilateral tubal occlusion or ligation
- Vasectomized partner
- Intrauterine device (copper or hormonal)
- Progestogen-only contraception (oral, injectable or implantable)
- Male or female condom with or without spermicide
- Sexual abstinence (only when it is the usual and preferred lifestyle of the subject)
Exclusion Criteria19
- \. History of primary hyperparathyroidism
- \. Use of combined hormonal contraceptive within the past 4 weeks
- \. Pregnancy or current pregnancy desire
- \. Prolactinoma associated with a known genetic syndrome
- \. Familial history of pituitary adenoma
- \. Renal failure (estimated glomerular filtration rate \<30 mL/min /1.73m2)
- \. IGF-1 level above the age-adjusted normal range of the local laboratory (IGF 1 \>1x ULNR)
- \. Idiopathic hyperprolactinemia (normal MRI) or presence of macroprolactinemia
- \. Concomitant mental condition rendering her unable to understand the nature, scope, and possible consequences of the study, and/or decompensated psychiatric disease (i.e. gambling or severe obsessive-compulsive disorder), as judged by the Investigator
- \. Chronic use of drugs related to hyperprolactinemia (such as metoclopramide, methyldopa, ranitidine, and opioid-related analgesics)
- \. Resistant prolactinoma, defined as non-normalization of PRL levels with 2mg/w of CAB
- \. Patients in the high dosage group who did not use 3.5mg/w of CAB for an entire 6 months (due to intolerance or non-compliance) or failed to achieve the target dose for any other reason
- \. Active malignant disease within the last 5 years, except basal and squamous cell carcinoma of the skin with complete local excision
- \. Any decompensated chronic condition (i.e. heart failure NYHA 3-4, diabetes with HbA1c \>8.5%, hypothyroidism with TSH \>10 mIU/L) that, in the opinion of the Investigator, would impede compliance, hinder completion of the study, compromise the well-being of the patient, or interfere with the study outcomes
- \. Male sex
- \. Cushing stigmas (moon face, muscle weakness, red striation) or suspicious
- \. Prior radiotherapy of the pituitary gland area for any reason
- \. Additional pituitary tumor-directed therapy, including temozolomide, everolimus, lapatinib, or cytotoxic chemotherapy
- \. Hepatopathy with AST/TGO or ALT/TGP \>3x the upper limit of normality
Interventions
Patients eligible for the study and randomized to the HIGH CAB arm will start oral CAB, 1 pill of 0.5mg, once a week. The dose will be increased by 0.5mg every week until the target dose of 3.5 mg/w. This initial low-dose-escalating regimen of 7 weeks will be used to prevent symptoms of intolerance. When 3.5 mg/w (1 pill every day) is reached, the patient must maintain this dose for 6 months. After this period, a 1-month de-escalation regime is implemented, reducing the dose by 1 mg/w (2 pills per week) until discontinuation.
The standard dosage group will receive conventional treatment as recommended by current guidelines: a low dose of CAB enough to achieve normoPRL for 2 years. All patients will start CAB with 1 pill (0.5mg) once a week. The CAB dose can be adjusted during visits if hyperPRL is not resolved (maximum dose 2mg/w to prevent inclusion of resistant cases). The expected dose used for this arm during follow-up is between 0.5 and 1 mg/w. After completion of 2 years of treatment, all patients will have CAB withdrawn, irrespective of tumor reduction, PRL levels or last CAB dose used.
Locations(16)
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NCT07463235