PF698 LUSUTROMBOPAG RELIABLY INCREASES PLATELETS REGARDLESS OF BASELINE PLATELET COUNTS IN THROMBOCYTOPENIC CHRONIC LIVER DISEASE PATIENTS UNDERGOING PLANNED INVASIVE PROCEDURES: RESULTS OF 2 PHASE 3 TRIALS

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Background:Lusutrombopag is an oral, small molecule thrombopoietin receptor agonist approved in Japan and US for improvement of thrombocytopenia, and in EU for severe thrombocytonia, associated with chronic liver disease in patients undergoing planned invasive procedures. The degree of thrombocytopenia may impact the treatment response to lusutrombopag and need for platelet transfusion.Aims:This analysis evaluates the increase in platelet count and maximum platelet count achieved according to baseline platelet count.Methods:L‐PLUS 1 and L‐PLUS 2 were two similar phase 3 multicenter, randomized, double‐blind, placebo‐controlled studies; L‐PLUS 1 (JapicCTI‐132323) was conducted in Japan and L–PLUS 2 (NCT02389621) was conducted globally. Patients with thrombocytopenia due to chronic liver disease received lusutrombopag 3 mg or placebo for up to 7 days prior to an invasive procedure scheduled 9–14 days after randomization. Patients were adults with platelet count (x109/L) <50 at baseline. Platelet transfusion was mandated if the platelet count remained <50 no more than two days prior to the planned invasive procedure. The change in platelet count over time was a key efficacy endpoint. A per‐protocol population from the two trials was integrated for this analysis; post‐platelet transfusion platelet counts were excluded from the analysis when calculating the proportion of patients who met a criterion and summary statistics for maximum platelet counts.Results:312 patients were randomized. Of the 270 patients in the per‐protocol population, 78.1% of patients in the lusutrombopag group (n = 137) achieved a platelet count ≥50 at least once during the study versus 30.1% of patients in the placebo group (n = 133). The platelet count increased by double or more in 47.4% and 3.8% in the lusutrombopag and placebo groups, respectively, and increased by 50% or more in 77.4% and 12.8%, respectively. The average maximum platelet count in the lusutrombopag group stratified according to baseline platelet count of <20, ≥20‐<30, ≥30‐<35, ≥35‐<40, and ≥40‐<50 was 56, 45, 64, 82, and 87, respectively (Figure). The average maximum change in platelet count in these strata were +41, 21, 32, 45, and 42, respectively.Summary/Conclusion:Patients on lusutrombopag experienced a clinically meaningful response in platelet count regardless of whether the baseline platelet count was above or below 35x109/L, thereby avoiding the need for use of platelet transfusion.image