P1638: EARLY USE OF ELTROMBOPAG IN ADULT PATIENTS WITH ITP WHO ARE REFRACTORY OR RELAPSED AFTER FIRST-LINE CORTICOSTEROID THERAPY – AN AD HOC ANALYSIS OF THE TAPER TRIAL RESULTS

Abstract

Background: Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by reduced platelet count (<100×109/L) and increased bleeding risk in the absence of other causes. It is categorized by disease duration from diagnosis: newly diagnosed (ndITP; ≤3 months [mo]), persistent (pITP; 3-12 mo), and chronic (cITP; >12 mo). Eltrombopag (EPAG), a thrombopoietin receptor agonist, is approved in Europe for the treatment of ITP lasting ≥6 mo in patients (pts) refractory to other treatments. The TAPER trial (NCT03524612) was designed to assess sustained response off treatment following EPAG tapering in adults with ITP of any duration, who were refractory/had relapsed after first-line corticosteroids. Aims: To conduct an ad hoc analysis of the ongoing TAPER trial, assessing initial response to EPAG therapy according to time since ITP diagnosis (ndITP, pITP, cITP). Methods: Pts with ≥6 mo of data, or pts who discontinued the study prior to Month 6 were included. Newly enrolled pts with <6 mo of data were excluded. Pts were grouped according to time since ITP diagnosis at baseline (<3, 3 to <6, 6 to ≤12, and >12 mo). The main analysis of hematologic response (ie, percentage of pts with platelet count thresholds of ≥30, ≥50, and ≥100 ×109/L achieved at least once without rescue therapy) was restricted to data from the first 2 mo (~Day 57) to ensure pts were on treatment. Safety analyses were restricted up to and including Month 6. Results: A total of 82/105 (78%) pts from TAPER were included. Median (range) age was 49 (18-88) years and 58.5% were female. In the first 6 months, the median (interquartile range [IQR]) duration of EPAG exposure was 5.3 (2.6-6.0) mo, and median (IQR) dose was 53.2 (37.5-69.6) mg/day. The proportions of pts with platelet counts equal to or above the specified thresholds were comparable across the time-since-ITP-diagnosis groups, ranging from 69% to 100% (Fig. 1). The median time to a platelet count of ≥50×109/L was also comparable across groups, ranging from 8 to 17 days, and the median (IQR) increase in platelet count to ~Day 57 was 84.5×109/L (36.5-165.6). The percentages of pts without World Health Organization Grade 1-4 bleeding events increased from Day 1 to ~Day 57 across all groups (<3 mo: 39.5%→84%; 3 to <6 mo: 61%→100%; 6 to ≤12 mo: 50%→88%; >12 mo: 70%→89%). The most common all-grade adverse events (AEs) were headache (pts: 18% [<3 mo], 22% [3 to <6 mo], 12.5% [6 to ≤12 mo], 10% [>12 mo]) and thrombocytopenia (pts: 21% [<3 mo], 17% [3 to <6 mo], 12.5% [6 to ≤12 mo], 0% [>12 mo]). One pt (6%; 3 to <6 mo) had grade ≥3 headache; 5 (13%; <3 mo), 2 (11%; 3 to <6 mo), and 2 (12.5%; 6 to ≤12 mo) pts had grade ≥3 thrombocytopenia. There were 3 treatment-related severe AEs (intentional product misuse [<3 mo], infectious diarrhea secondary to EPAG, and pulmonary embolism [both 6 to ≤12 mo]). Two deaths were reported by the cut-off date (central nervous system hemorrhage [n=1; <3 mo]; intracranial hemorrhage [n=1; 3 to <6 mo]) that were not considered study drug related. Image:Summary/Conclusion: The data show that EPAG achieved comparable rates of platelet response and reduced the frequency and severity of bleeding events in pts with ndITP, pITP, and cITP. Safety findings were comparable across the 4 groups, and aligned with the well-established safety profile of EPAG. These findings suggest that EPAG is as efficacious and well tolerated in pts who receive it early following diagnosis as in those who receive it later.