Susan L Samson, MD, PhD, FRCPC, FACE, Chair of Endocrinology at Mayo Clinic in Jacksonville, Florida, discusses positive efficacy data from the open-label extension of the OPTIMAL study of oral octreotide, an orphan drug that was approved for the treatment of acromegaly in 2020. Data from the open-label extension was presented at the ENDO 2022 Annual Conference.

Acromegaly is a rare endocrine disorder in which the body secretes too much growth hormone in adulthood, usually as a result of a pituitary tumor.  Since the increased growth hormone occurs past puberty, the changes in bone structure can be very gradual. As a result, it can take several years for a person with acromegaly to be diagnosed.

As Dr. Samson explains, the OPTIMAL trial (NCT03252353) was a randomized, double-blind, placebo-controlled, phase 3 clinical trial of octreotide capsules in 56 adult acromegaly patients whose disease was controlled by injectable somatostatin analogs (octreotide or lanreotide). Eligible patients were then randomized 1:1 to octreotide capsules or placebo. The primary endpoint of the trial was the proportion of patients who maintained their biochemical response (insulin-like growth factor I [IGF-1] levels less than 1.0 × upper limit of normal [ULN]), at the end of the 9-month, double-blind, placebo-controlled period. The OPTIMAL study met the primary endpoint and all secondary endpoints which led to the US approval of oral octreotide, the first oral somatostatin analog, for the long-term maintenance treatment in acromegaly patients who have responded to and tolerated treatment with injectable octreotide or lanreotide.

After the 9-month, double-blind, placebo-controlled period, patients were eligible for enrollment in the open-label extension study to evaluate the long-term efficacy and safety of oral octreotide. One of the key findings presented at ENDO 2022 was that maintenance of biochemical response (defined as IGF-I levels below ULN) to oral octreotide was durable up to 96 weeks. 100% of subjects (n= 17) who were responders at week 48 and 93% of subjects overall (n=29) demonstrated a biochemical response at week 96. Median exposure to oral octreotide was 2.1 years, with exposure >3 years for 5 patients.

To learn more about acromegaly and other endocrine disorders, visit