Endocrine Abstracts

JOINT1203

Combined therapy of somatostatin analogue and growth hormone receptor antagonist for the management of acromegaly. A 35-year-old woman was diagnosed with acromegaly in January 2021. She was consulted by an endocrinologist due to enlarged hands and feet. She also complained of a change in facial features, weight gain, excessive sweating, and severe headaches. Laboratory tests confirmed the diagnosis of acromegaly. MRI of the pituitary gland revealed a pituitary tumor of 22 × 32 × 26 mm. She was referred to the neurosurgery department. The surgery was not complete, the remnant tumor was 25 × 28 × 16 mm and comprised the right cavernous sinus. The patient was suggested to start radiotherapy but did not agree. A first generation somatostatin analogue was introduced. IGF-1 concentration was 492 ng/dl (115-307). Due to the lack of improvement, a second generation of somatostatin analogue was started. At the beginning patient received 40 mg of pasireotide. After a few months, IGF-1 concentration was still elevated [416 ng/dl, (115-307)]. Then the dose was increased to 60 mg. During the nine months of treatment, a normal IGF-1 level was observed only once (306 ng/dl, (115-307)], in January 2023. The patient was dismissed from this treatment due to the lack of normalization of IGF-1 and the poor tumor shrinkage. The patient underwent radiotherapy in June 2023. It was not possible to introduce Gamma Knife radiosurgery. It was decided to apply irradiation with a total dose of 54 Gy. Severe headache appeared soon after cessation of pasireotide and aggravated after radiotherapy. It was decided to administer pegvisomant until the effects of radiotherapy appeared. Before administration of pegvisomant, an MRI was done and revealed a residual tumor measuring 17 mm x 20 mm x 20 mm infiltrating the right cavernous sinus and almost completely encasing the internal carotid artery segment. The tumor grew between the base of the right frontal lobe and the inner surface of the right temporal pole toward the optic canal. It did not infiltrate the right optic nerve or the optic chiasm. The initial dose was 10 mg in October 2023. The permanent reduction in IGF-1 level was achieved with a dose of 20 mg. Due to a headache that impaired quality of life significantly, pasireotide was administered again as emergency therapy in November 2023. It was very effective in managing headaches. The patient continues therapy addressing both IGF-1 concentration and the most disturbing symptom.