Oral Octreotide Capsules Lowered Incidence and Improved Severity of Acromegaly Symptoms Compared to Injectable Somatostatin Receptor Ligands—Results From the MPOWERED Trial

Background: Patients with acromegaly may have high symptom burden. The phase 3 MPOWERED trial assessed control of acromegaly by oral octreotide capsules (OOC; MYCAPSSA(®)) in comparison to injectable somatostatin receptor ligands (iSRLs) in patients responding to both OOC and iSRLs. iSRLs have been first-line medical treatment for patients with acromegaly for decades. OOC are newly approved in the US for patients previously controlled on iSRLs. Methods: Eligibility criteria for MPOWERED included acromegaly diagnosis, biochemical control of acromegaly (insulin-like growth factor I <1.3 × upper limit of normal; mean integrated growth hormone, <2.5 ng/mL) and ≥6 months’ iSRL (octreotide, lanreotide) treatment. Eligible patients entered a 26-week Run-in phase to determine the effective OOC dose; responders at week 24 then entered a 36-week randomized controlled treatment (RCT) phase receiving OOC or iSRLs. Acromegaly symptom number and severity (mild to severe, 1-3) were collected. Total score was calculated by summating all severity scores (Acromegaly Index of Severity [AIS]). Symptom results were assessed using total AIS score and proportion of patients experiencing individual symptoms. Results: At beginning of Run-in, average AIS score of 92 randomized patients was 4.52, representative of symptoms experienced while previously receiving iSRLs. After 26 weeks’ OOC treatment at end of Run-in, average AIS score was significantly reduced to 3.46 (P<0.001). More than 80% of patients on OOC improved or maintained AIS score during Run-in compared to baseline. Over this 26-week period, there was a significant reduction in extremity swelling (P=0.01) and fatigue (P=0.03). During the RCT, of patients randomized to OOC (n=55), 73% maintained or improved AIS score, and 75% maintained or reduced overall number of active symptoms. In comparison, 68% of those randomized to iSRLs (n=37) maintained or improved AIS score, and 70% maintained or reduced overall number of active symptoms. Conclusion: Results from MPOWERED show that patients receiving OOC had significant improvement in number and severity of acromegaly symptoms after switching from iSRLs. These findings validate previous results from a phase 3 study of OOC in acromegaly in which patients switching to OOC from iSRLs showed significant reduction in joint pain, extremity swelling, and fatigue.(1) (1)Melmed S, et al. JCEM. 2015;100(4):1699-1708.