The optimal choice of second-line treatment for immune thrombocytopenia (ITP) is unclear.
Guidelines recommend either rituximab, splenectomy, or thrombopoietin receptor agonists
(TPO-RA). There is, however, scarce data comparing treatment patterns, outcomes and
resource utilization across second-line treatments. Despite Canada's universal healthcare
system, publicly funded access to second-line ITP therapies is highly variable across
To describe treatment patterns and compare health service utilization and outcomes
among recipients of second-line rituximab and TPO-RA for ITP.
In this multicentre retrospective cohort study, we included adults who received second-line
ITP therapies rituximab, eltrombopag and romiplostim (2012-2020) in Alberta, Canada.
Patients were identified through a provincially-funded special drug access (STEDT)
program. We examined treatment patterns, predictors of second-line treatment, hospitalizations,
blood product utilization, and outcomes. Kaplan-Meier survival curves were used to
estimate the cumulative incidence of ITP-related hospitalizations (bleeding or infections),
overall survival (OS) and relapse-free survival (RFS). Cox proportional hazards regression
was used to examine the impact of second-line therapy on OS.
223 patients received rituximab (67 %), eltrombopag (29 %), and romiplostim (4 %).
TPO-RA recipients experienced significantly longer time from ITP diagnosis to second-line
therapy compared with rituximab recipients (15.9 vs 6.7 months, P < 0.0001), accompanied by significantly higher platelet and IVIG utilization prior
to second-line therapy. Age (adjusted odds ratio [aOR] 1.04, 95 % CI 1.02–1.07, P < 0.0001) and prior intracranial hemorrhage (aOR 12.7, 95 % CI 1.6–272.8, P = 0.03) were significant predictors of second-line TPO-RA. TPO-RA is associated with
a trend towards longer median RFS (6.3 vs 3.8 years, P = 0.06) compared with rituximab, and similar rates of ITP-related hospitalizations,
major bleeding, and thromboembolism. Age, time period, and Charlson comorbidity index,
but not second-line ITP therapy, were significant predictors of OS.
Our study identified older age and intracranial hemorrhage as predictors of second-line
TPO-RA prescription in a real-world practice. There were no significant differences
in hospitalizations and outcomes between second-line rituximab and TPO-RA, although
delayed initiation of TPO-RA was associated with higher blood product utilization.