ECE2020 Oral Communications Pituitary and Neuroendocrinology (7 abstracts)
Background: Many patients with acromegaly report limitations of long-acting somatostatin receptor ligand (SRL) injections, including ongoing disease symptoms near cycle-end and injection-site pain. Oral octreotide capsules (OOC) may provide an alternative to monthly injections. The phase 3 CHIASMA OPTIMAL study assessed efficacy and safety of OOC in patients with acromegaly controlled on injectable SRLs.
Methods: A multinational, randomized, placebo-controlled study was conducted in 56 patients ≥18 years of age with active acromegaly (IGF-I ≥1.3 × ULN) and average IGF-I ≤ 1.0 × ULN on stable dose of SRL injections (octreotide or lanreotide, ≥3 months). At baseline (1 month after last injection), patients were randomized to OOC or placebo (28/group) for 36 weeks, followed by an optional open-label extension (OLE). The primary endpoint was proportion of patients maintaining biochemical response, defined as IGF-I ≤ 1.0 × ULN (2-value average at weeks 34 and 36). Secondary endpoints included need for rescue with injectable SRLs, GH response (GH < 2.5 ng/mL), and time to loss of IGF-I response (IGF-I > 1.0 and $1.3 ×ULN for 2 consecutive visits). Safety and tolerability were assessed.
Results: The primary endpoint was met, as 58% of patients receiving OOC maintained IGF-I response vs 19% receiving placebo (P = 0.008). Mean IGF-I levels in patients receiving OOC were within the reference range at treatment end (0.97 × ULN) vs patients receiving placebo (1.69 × ULN). All secondary endpoints were met. Of patients receiving OOC, 75% completed 36 weeks without need for rescue therapy. However, 68% of the placebo group required rescue therapy. GH response was maintained at week 36 in a significantly larger proportion of patients receiving OOC than placebo (78% vs 30%; P = 0.001). Median time to loss of IGF-I response was not reached by the end of the study for patients receiving OOC vs 16 weeks for the placebo group (P < 0.0001). Five patients in the placebo group had IGF-I levels in the reference range at the end of 36 weeks. Only 2 (7% of placebo group) did not meet loss of response criteria anytime throughout the study. OOC were safe and well tolerated; no new/unexpected safety signals were observed. Most patients (55/56) experienced at least one treatment emergent adverse event; most were mild or moderate in intensity. Overall, 90% of patients who completed the trial on OOC opted to enter the open label extension phase.
Conclusion: These phase 3 data demonstrate OOC to be potentially safe and effective for treating adults with acromegaly.
05 Sep 2020 - 09 Sep 2020