MON-030 - Eleven Years of Primary Medical Therapy with Somatostatin Analogs and Pegvisomant in A Young Man with Acromegaly

Background:
Uncontrolled acromegaly is associated with higher morbidity and mortality rates with increased risk of cardiomyopathy, diabetes, and cancer. While first line treatment of acromegaly is usually surgical intervention to remove the source of growth hormone excess (usually from a pituitary adenoma), medical therapy may be utilized for patients who decline surgery or are not surgical candidates. In this case, we demonstrate the experience of a young man with acromegaly who has been on primary medical therapy with somatostatin analogs and pegvisomant for more than a decade and describe its impact on insulin-like growth factor 1 (IGF-1) and pituitary tumor volume over time.

Case Description:
A 27-year-old male presented to clinic for follow-up of ongoing acromegaly. He was diagnosed at age 16 after presenting with tall stature, increased size of hands and feet (shoe size 16), macroglossia, and need for multiple revised fittings of his dental braces. At time of diagnosis, IGF-1 was elevated >1600 ng/mL (Z-score >13), and magnetic resonance imaging (MRI) revealed an invasive pituitary mass measuring 29 mm in maximum dimension. Other labs were notable for hyperprolactinemia and hypogonadism. Surgery was strongly recommended, but due to personal reasons, he declined and elected to start medical therapy instead. He was started on octreotide long-acting release, later switching to lanreotide Autogel at a dose of 120 mg every 4 weeks. After two years, IGF-1 improved to 738 ng/mL (Z-score +5.6), and tumor size decreased to 18 mm. Pegvisomant was then added at 60 mg 2 times per week, and IGF-1 was normal one year later (439 ng/mL, Z-score +2.0) but soon became elevated again.

Ten years after addition of pegvisomant, his latest MRI shows a maximum tumor dimension of 10 mm, indicating 66% reduction in maximum tumor dimension since diagnosis. IGF-1 remains high at 870 ng/mL (Z-score +4.3). He continues to have hypogonadism with inconsistent adherence to testosterone replacement and has since developed pre-diabetes. His echocardiogram shows mild LV enlargement and aortic root dilation but normal ejection fraction. Treatment options of surgery, addition of cabergoline, and switch to pasireotide have all been discussed and recommended to avoid complications of GH/IGF-1 excess, but the patient has so far continued to decline these options as he overall feels well.

Conclusion:
To our knowledge, this is the longest reported case of primary medical therapy in the treatment of acromegaly. While some studies have demonstrated effectiveness of long-term medical therapy for IGF-1 normalization and tumor shrinkage, our patient continues to have markedly elevated IGF-1, placing him at risk for continued complications of acromegaly. Our case underscores the need for individualized treatment approaches and counseling strategies for biochemical control in patients with acromegaly who do not undergo surgery.

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