Findings of Feasibility Assessment From Multicenter Clinical Trials of Antithrombotic Therapy in Pediatric Venous Thromboembolism

Abstract 4323

BACKGROUND:Two major multicenter pediatric randomized controlled clinical trials (RCTs) in pediatric venous thromboembolism (VTE) have been conducted in the last decade, and each was closed early due to poor accrual. With the recent trend in reduced federal grant support for clinical trials, an emphasis on demonstration of feasibility is critical.OBJECTIVE: In order to inform the design and execution of future RCTs in pediatric VTE, we sought to report findings of feasibility assessment from two ongoing and one proposed clinical trials in the field. METHODS: In the UNBLOCK study (ongoing phase 1 trial of bivalirudin in acute DVT; clinicaltrials.gov registration #NCT00812370), feasibility was assessed informally in 2008/9 during grant development teleconferences and early investigator meetings. In the Kids-DOTT trial (ongoing phase 3 RCT of shortened vs. conventional duration of therapy in acute VTE associated with a transient/reversible clinical risk factor; NCT00687882), feasibility was assessed in 2005 and updated in 2011 using standardized questionnaires, with response data summarized via descriptive statistics. The latter approached was also used in 2011 for the PHLO trial (proposed phase II/III RCT of catheter-directed thrombolysis followed by therapeutic anticoagulation vs. anticoagulation alone in completely veno-occlusive acute DVT of the proximal leg). RESULTS: Response rate (Kids-DOTT and PHLO questionnaires) was 100%. Number of investigative sites/principal investigators assessed and geographical distribution, by trial, were as follows: UNBLOCK: n=6 (all USA); Kids-DOTT: n=26 (25 USA, 1 Canada); PHLO: n=7 (all USA). Of the 26 site PIs in Kids-DOTT, 84% reported past experience with 5 or more trials, with a median experience of 20 per PI. Across all 3 trial feasibility assessments, all but one site used electronic health records in clinical care, and all but one investigative team had trial experience in using electronic data capture systems. With regard to size of the screening population for pediatric VTE trials, Figure 1 shows the reported average annual volume of new pediatric VTE cases managed by each Kids-DOTT investigator/site, using data from the prior 2 years. All sites reported use of inpatient/consult lists in screening efforts. CONCLUSIONS: These findings indicate appropriate site experience and capacity to execute multicenter clinical trials in pediatric VTE. Therefore, feasibility of ongoing and future trials in the field is more likely related to such issues as: suitability of funding and number of sites to targeted enrollment; experience/capabilities of the clinical coordinating and data coordinating centers; and pragmatic protocol design, particularly eligibility criteria, enrollment/randomization windows, and frequency, timing, and invasiveness of follow-up and endpoint determinations.

Disclosures:

No relevant conflicts of interest to declare.

Figure 1.

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Number of New Pediatric VTE Patients per Year

Figure 1.

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Number of New Pediatric VTE Patients per Year

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