Remission in most patients can be evaluated using insulin-like growth factor I (IGF-I) levels measured 6 weeks postoperatively, although if the IGF-I is only mildly elevated, normalization may occur by 3-6 months.
Long-term follow-up demonstrates that biochemical control is achieved and maintained in about 50% of patients treated with stereotactic radiosurgery (SRS) or fractionated radiotherapy (FRT). However, ongoing monitoring is required because hypopituitarism develops in up to one-third of patients with normal pituitary function.
Injectable Somatostatin Receptor Ligands
In patients on primary lanreotide treatment (120 mg therapy every 4 weeks), a more favorable long-term biochemical response is predicted by older age, female sex, lower IGF-I levels, and tumor T2 magnetic resonance imaging (MRI) hypointensity, at baseline.
As confirmed by several studies, pasireotide long-acting release (LAR) is effective in some patients who have not achieved control with lanreotide or octreotide LAR. However, careful monitoring for glycemic side effects is needed owing to high rates of treatment-induced hyperglycemia and diabetes mellitus.
Pegvisomant demonstrated a 73% biochemical control rate, with transient transaminase elevation occurring at a very low rate and 6.8% of patients demonstrating MRI-observable tumor growth. Data were culled from a 10-year follow-up from ACROSTUDY.
Patients needing combination therapy can effectively be treated at a reasonable cost with low-dose octreotide LAR or lanreotide, plus weekly pegvisomant.
Even at low doses of pegvisomant, biochemical control rates of more than 70% can be achieved with a combination of pasireotide and pegvisomant. However, no improvement in the high rates of pasireotide-induced hyperglycemia results from the addition of pegvisomant.
Oral Octreotide Capsules
If injectable octreotide or lanreotide has produced a complete or partial biochemical response, the administration of oral octreotide capsules (OOCs) is suitable.
The initiating dose of OOCs is 40 mg/day, administered in twice-daily 20 mg capsules taken either 1 hour prior to mealtime or 2 hours following a meal (for maximization of bioavailability). However, according to clinical study data, the majority of patients may benefit most from a starting dose of 60 mg/day.
OOC initiation should occur at the time that the next somatostatin receptor ligand injection had been scheduled.
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Cite this: Acromegaly Clinical Practice Guidelines (PS, 2021) - Medscape - Oct 29, 2021.