Susan L Samson, MD, PhD, FRCPC, FACE, Chair of Endocrinology at Mayo Clinic in Jacksonville, Florida, discusses the positive safety data from the open-label extension of the OPTIMAL study of oral octreotide, a drug approved for the treatment of acromegaly. 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. Overall, the safety profile of oral octreotide during the open-label extension period was consistent with previous studies and with that of injectable somatostatin analogs. No serious adverse events were reported in the open-label extension study. Interestingly, Dr. Samson notes that patients who entered the open-label extension study naive to oral octreotide tended to have fewer adverse events compared to patients who were in the treatment arm of the clinical trial. One potential reason for this is that patients in the placebo arm were initially given 60 mg of oral octreotide when they entered the open-label extension, while those in the treatment arm were dose titrated from 40 mg per day to up to a maximum of 80 mg per day. Dr. Samson suggests that the higher dose may have better control of the manifestations of acromegaly which could explain the reduction in adverse events. Further evaluation is needed to determine this.

To learn more about acromegaly and other endocrine disorders, visit