Abstract
Introduction
Patients with myeloproliferative neoplasms (MPN) typically experience debilitating symptom profiles and profound quality of life (QoL) decrements. Characterizing symptom burden in MPN clinical trials is vital to inform efficacy analyses. Previous studies have shown clinicians and researchers depend on patient-reported outcomes (PROs) to glean disease-related symptoms and signs of QoL decline. The current literature also shows that integrating PROs into the routine care of patients with cancer is associated with increased survival compared with usual care. However, the extent to which PROs are employed in MPN clinical trials is undescribed. ClincalTrials.gov is a registry of clinical trials mandated by the US Congress and implemented in 2000 by the National Institutes of Health. This study used data from ClinicalTrials.gov to evaluate the characteristics of MPN clinical trials over time and their use of PROs as primary and secondary outcomes.
Methods
The statistical software R and the rclinicaltrials package were used to download data from ClinicalTrials.gov. Trial data were included in this study if the following criteria were met: (1) the words essential thrombocythemia, polycythemia vera, myelofibrosis, or myeloproliferativeneoplasm (MPN) were used in the registered primary disease condition or official trial title; (2) the trial start date was between January 1, 2000 - July 1, 2018; (3) primary/secondary outcome data were available. Trial outcome data were then parsed for PRO text phrases including MPN-Symptom Assessment Form, quality of life, questionnaire, patient-reportedoutcome, and more specific PRO items (e.g., bone pain, concentration problems, and depression). Descriptive statistics and regression analysis were used to assess rates of primary/secondary outcomes over time.
Results
Clinical trial characteristics
There were 535 trials satisfying the inclusion criteria. Since 2000, the number of registered MPN-related clinical trials ranged from 11 to 36 trials per year with 28 trials registered annually on average (Figure 1). Of the 535 trials, 470 (88%) were interventional and 65 (12%) observational. Trials often employed multiple intervention types including: drug (77%); procedure (28%); biological (19%); radiation (13%); genetic (3%); behavioral (2%); device (2%); dietary supplement (1%); other (24%) [percentages do not sum to 100% as categories are not mutually exclusive]. Eligibility criteria varied widely, though most used 18 years old as the minimum age requirement (71%; 379/535) and nearly all included both genders (>99%; 533/535).
PRO outcomes over time
Of the 535 MPN trials, the number of primary outcomes within MPN trials did not change over time (p=.50) with an average of 1.6 per trial. Around 8% of MPN clinical trials had PRO-related primary outcomes; this rate also did not change over time (Figure 1: solid red line; p=.97). However, the total number of secondary outcomes per trial has increased since 2000 (p<.001). From 2000-2005, 2006-2011, and 2012-2018 there was an average of 2.8, 3.3, and 5.2 secondary outcomes per trial, respectively. Also, the proportion of MPN clinical trials with PRO-related secondary outcomes has increased steadily over time (Figure 1: dashed blue line; p<.001). On average, from 2000-2005, 2006-2011, and 2012-2018 the proportion of MPN clinical trials with PRO-related secondary outcomes increased from 8% to 23%, to 33%.
Conclusion
Analysis of ClinicalTrials.gov data suggest that patient-reported outcomes are being implemented into MPN clinical trials at increasing rates. While this suggests that MPN trials are becoming more patient-centered, PROs are included more often as secondary endpoints than primary endpoints. This analysis also suggests an increase in the number of secondary endpoints in recent years in MPN clinical trials, consistent with observed trends of growing complexity and increasing amount of data captured in clinical trials in general.
Mesa:Ariad: Consultancy; Galena: Consultancy; Gilead: Research Funding; Promedior: Research Funding; Incyte: Research Funding; Novartis: Consultancy; CTI: Research Funding; Celgene: Research Funding. Scherber:Orphan Pharmaceuticals: Honoraria; Incyte: Consultancy. Dueck:Bayer: Employment; Phytogine: Employment; Pfizer: Honoraria.
