Tapering cabergoline (CAB) levels can still maintain normal prolactin (PRL) levels in patients with macroprolactinomas, according to a study recently published in the Journal of the Endocrine Society.
Researchers led by Phillipe Chanson, MD, of Hopital de Bicetre in Le Kremlin-Bicetre, France, point out that CAB is “currently the dopamine agonist (DA) of choice” in treating macroprolactinomas because it’s the most effective drug. They also note that Endocrine Society guidelines recommend continuing DA therapy for a minimum of two years once PRL levels have normalized, and that between 24% and 75% of patients maintain a normal PRL level after DA withdrawal. However, they write, there are few data on the necessary dose of CAB to achieve and maintain normal PRL levels.
The team retrospectively studied 260 patients in two groups: one group whose doctors chose to maintain the CAB dose – the fixed-dose group – and one group whose doctors chose to taper the CAB dose – the de-escalation group. PRL levels normalized in 157 patients, with 84 of these patients tapering their CAB doses, 77 of which maintained normal PRL levels. De-escalation even worked in patients who required larger doses, so-called “CAB resistant patients.” The authors write that tapering had no negative long-term effect on tumor size.
“A low effective initial dose of CAB seems to be a good predictor of successful subsequent CAB withdrawal,” the authors write. “In our experience, when a very low maintenance dose and/or a long dosing interval has been achieved, complete CAB withdrawal can be attempted. However, lengthy follow-up is necessary, because CAB has a very long half-life.”
Based on these results, the researchers conclude that the CAB dosage to maintain normal PRL levels is lower than the initial dosage used to normalize PRL levels, and that tapering is almost always successful, even in the CAB resistant patients. They go on to write, “This tapering strategy has two potential benefits: it reduces the possible risks associated with long-term CAB exposure, and it identifies patients in whom hyperprolactinemia is likely to recur if CAB is discontinued. Importantly, CAB de-escalation does not result in renewed tumor growth.”
Read the study here.