Evolution of the Designs of the Sitagliptin (SITA) Pediatric Clinical Studies

Approved antihyperglycemic therapies for pediatric patients with T2D are currently limited to metformin (MET) and insulin. SITA is being evaluated in 3 studies in patients 10-17 years of age with T2D: SITA as initial oral therapy, MK-0431 P083; SITA as add-on to MET administered as a fixed dose combination (FDC), MK-0431A P170; and SITA as add-on to MET extended-release administered as a FDC of SITA and MET XR, MK-0431A XR P289. The studies, conducted to fulfill post-marketing requirements, and a Pediatric Investigation Plan (EU), were initiated between 2011 and 2013; enrollment completed in 2018. Study protocols were amended since initiation to accommodate regulatory agency requirements, reduce patient burden related to study conduct, and improve patient accrual. Major amendments to the protocols, their rationales, and their impacts are summarized (Table) and demonstrate the flexibility that may be required to enroll such studies. The impact on enrollment of 2 amendments common to all 3 studies were quantifiable. Of patients randomized after approval of an amendment that broadened the A1C entry criterion (from lower limit of 7.0% to 6.5%), ∼34% in P083, ∼20% in P170 and ∼20% in P289 had a baseline A1C between 6.5% and 6.9%. Of patients randomized after approval of an amendment to include patients on background insulin, 11% of patients in P083, 22% in P170, and 19% in P289 enrolled on background insulin. Disclosure R. Shankar: Employee; Spouse/Partner; AstraZeneca. Employee; Self; Merck & Co., Inc. Employee; Spouse/Partner; NGM Biopharmaceuticals. V.P. Pozharskaya: Employee; Self; Merck & Co., Inc. K. Leight: Employee; Self; Merck & Co., Inc. Stock/Shareholder; Self; Merck & Co., Inc. R.S. Newfield: Research Support; Self; Bristol-Myers Squibb Company, Daiichi Sankyo Company, Limited, Eli Lilly and Company, University of California and Rady Children's Hospital, San Diego. A. Deeb: None. R. Garcia: None. C.A. Rosario: None. C.K. Saha: Research Support; Self; Indiana University School of Medicine. N. Shehadeh: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Novo Nordisk Inc., Sanofi-Aventis. Speaker's Bureau; Self; Eli Lilly and Company, Merck Sharp & Dohme Corp. Y. Samoilova: None. S.S. Engel: Employee; Self; Merck & Co., Inc. Stock/Shareholder; Self; Merck & Co., Inc. M.Y. Jalaludin: Advisory Panel; Self; Novo Nordisk Inc. Research Support; Self; Merck Sharp & Dohme Corp., Novo Nordisk Inc. P. Zeitler: Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Janssen Research & Development, Merck & Co., Inc., Novo Nordisk Inc. K.D. Kaufman: Employee; Self; Merck & Co., Inc. Stock/Shareholder; Self; Merck & Co., Inc. Funding Merck & Co., Inc.