Sponsor-Level Accountability on ClinicalTrials.gov: Modality-Stratified Backlog, Ghost Protocols, Overdue Debt, and Narrative-Field Gaps in 249,507 Older Closed Studies

Abstract

ClinicalTrials.gov hosts hundreds of thousands of closed interventional studies, yet systematic accountability for missing results, absent narrative fields, and lagging actual-record discipline has rarely been mapped at the sponsor level across multiple dimensions simultaneously. This article synthesises 15 linked analyses of 249,507 eligible older closed interventional studies drawn from the March 29, 2026 full-registry snapshot. The unifying methodological thesis is that pooled, single-dimension sponsor rankings systematically understate backlog concentration: hiddenness is structurally stratified by intervention modality, geography, text-field type, and silence depth, and only modality-disaggregated, multi-lens rankings reveal which sponsors are repeat offenders across dimensions. Key quantitative findings include: GlaxoSmithKline carried 1,826 detailed-description gaps and 1,033 missing-results studies in drug portfolios, making it the largest named contributor on both text and results dimensions; Boehringer Ingelheim accumulated 15,166 unresolved overdue years and a mean unresolved age of 17.7 years; Cairo University led sponsor ghost excess at 228 studies, and Assistance Publique — Hôpitaux de Paris led adjusted excess no-results at 265 studies; missing actual enrollment corresponded to a 100.0 percent no-results rate and a 62.8 percent ghost-protocol rate, establishing actual-field compliance as the strongest single structural predictor of result opacity; and industry no-results rates rose from 27.3 percent in mixed U.S.-plus-non-U.S. portfolios to 70.9 percent in non-U.S.-only portfolios. Together, these analyses establish a multi-lens accountability framework in which sponsor rank depends fundamentally on the dimension of hiddenness being measured.