Paper
Primary-outcome text gaps are narrower than general narrative gaps, but they remove the single line that matters most for understanding study intent.
Which named sponsors most often leave older CT.gov study pages without primary outcome descriptions, obscuring what the main endpoint was meant to measure? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot and ranked sponsors with at least 100 studies. We defined a primary-outcome gap as a missing primary outcome description, then compared sponsor stock, rate, and sponsor-class patterns. GlaxoSmithKline led the sponsor primary-outcome-gap stock table at 820 studies, followed by Boehringer Ingelheim at 759, Sanofi at 749, and Pfizer at 645. Ranbaxy Laboratories Limited had the sharpest large-sponsor primary-outcome-gap rate at 98.0 percent, while Mylan Pharmaceuticals reached 94.3 percent and NIH reached 30.7 percent as a sponsor class. Missing the primary outcome description removes the line telling readers what the main endpoint was, even when other registry fields remain visible. These gaps describe missing registry fields and do not by themselves establish legal non-compliance or missing outcome data elsewhere.