Abstract: PF661

Type: Poster Presentation

Presentation during EHA23: On Friday, June 15, 2018 from 17:30 - 19:00

Location: Poster area

Background

Prednisolone is most widely used first-line therapy for treatment of newly diagnosed ITP. But most of the adults with ITP relapse after initial response to steroid. To intensify frontline therapy, Rituximab (375 mg/m², weekly for four weeks) in combination with high dose dexamethasone (HDD), was used in newly diagnosed ITP and showed higher long-term remission rates compared with dexamethasone alone. Subsequently, non-randomized trials used low-dose rituximab (100 mg, weekly for four weeks) in combination with HDD in treatment naïve adult patients with ITP. To date, there have been no randomized trials comparing low-dose rituximab plus prednisolone with prednisolone alone as frontline therapy in adult patients with ITP. 

Aims

In this randomized trial we compared efficacy and safety of Low-dose rituximab plus prednisolone with prednisolone alone in newly diagnosed adult patients with ITP.

Methods

In this study, we enrolled newly diagnosed treatment naïve adult (≥ 18 years) ITP patients with symptomatic bleeding manifestations between February 2016 to October 2017. Total 60 patients were evaluated for eligibility and at randomization 8 patient were excluded from the study (pregnant = 1, HIV positive = 1, HBs Ag positive = 1, ANA positive = 1,  three patient received IVIg, one received high dose methyl prednisolone). Fifty-two patients were randomly assigned to two treatment arms. Twenty-six patients received prednisolone 1 mg/kg for 4 weeks followed by tapering of prednisolone over another 4 weeks. Other twenty-six patients received additional rituximab 100 mg weekly, four doses.  

Results

The initial responses were measured at one month. In Rituximab-Prednisolone arm 18 (69.2%) patients achieved CR and 3 (11.5 %) achieved R, mounting an Overall response (OR) to 80.7 %. In prednisolone arm, OR, CR, and R were achieved by 18 (69.2%), 13(50%), and 5(19.2%) patients, respectively. There was no statistically significant difference in initial response between two cohorts (p=0.368). At six months, in Rituximab-Prednisolone arm CR, R and OR were 65.4%, 11.5%, and 76.9%, respectively. Prednisolone arm showed CR, R, and OR of 26.9%, 11.5%, and 38.4 %, respectively (p=0.013). One year response data was available for 19 patients of RP arm and for all the 26 patients of Prednisolone arm. At one year, Rituximab- Prednisolone arm and Prednisolone arm showed CR rates of 52.6% (10/19) and 15.4% (4/26), respectively (p=0.008).

At three months, five patients (27.8%) of Prednisolone arm relapsed, whereas no patient of Rituximab-Prednisolone arm relapsed at 3 months (p=0.01). At six months, only one patient (4.8%) of  Rituximab-Prednisolone arm relapsed, whereas 8 patients (44.4%) of Prednisolone arm relapsed at 6 months (p=0.003). One year relapse data were available for 14 patients of the Rituximab-Prednisolone arm and for all the 18 patients of Prednisolone arm. At one year, 4 patients (28.6%) of the Rituximab-Prednisolone arm and 14 patients (77.8%) of Prednisolone arm relapsed (p=0.002).

Eleven patients (42.3%) of the Rituximab-Prednisolone arm and 10 (38.5%) patients of Prednisolone arm experienced adverse effects. All the adverse effects were grade 1 or grade 2. 

Conclusion

The combination of  low-dose Rituximab plus Prednisolone as frontline therapy for adult patients with newly diagnosed primary immune thrombocytopenia is well tolerated and induces a higher long-term response and lower incidence of relapse than Prednisolone alone.

Session topic: 33.  Platelets disorders

Keyword(s): ITP, Prednisolone, Rituximab