Immune Thrombocytopenia (ITP)
The safety and efficacy of WAYRILZ in adult patients with primary persistent or chronic ITP was evaluated in a randomized, double-blind (DB), placebo-controlled, parallel-group study consisting of 24 weeks of blinded treatment followed by an open-label (OL) period [LUNA-3 Study (NCT04562766)]. Patients received an initial 12 weeks of DB period treatment. Those who achieved platelet count response at 12 weeks were eligible to continue the full 24-week DB period. The patients enrolled in this study had an unsustained response to either intravenous immunoglobulin (IVIg/anti-D) or corticosteroid (CS) or had a documented intolerance or insufficient response to any appropriate course of standard-of-care ITP therapy.
Patients were randomized 2:1 to receive WAYRILZ 400 mg or placebo twice daily and randomization was stratified based on prior splenectomy (yes/no) and severity of thrombocytopenia (platelet count <15 ×10
Concomitant ITP medicines [oral CS and/or thrombopoietin receptor agonist (TPO-RA)] were allowed at stable doses at least 2 weeks before the start of the study and throughout the DB period.
In the LUNA-3 Study, 202 patients were randomized and treated, 133 to the WAYRILZ group and 69 to the placebo group. At baseline, the median age was 47 years (range: 18 to 80 years), 63% were female, 62% were Caucasian, 32% Asian, 1% were Black or African American, 2% were American Indian or Alaska native, 20% were Hispanic or Latino/a, and 77% were not Hispanic or Latino/a. Baseline demographics were generally similar across groups with the exception of sex which was 59% female in the WAYRILZ group and 71% in the placebo group.
At baseline 93% of patients had chronic ITP (i.e., for 1 year or longer), with a median time since ITP diagnosis of 7.69 years (range: 0.3, 52.2), and 28% had undergone splenectomy. The median platelet count was 15.3 × 10
During the DB period, the median duration of exposure was 98 days (range: 22 to 182) and 84 days (range: 17 to 173) for the WAYRILZ group and placebo group, respectively. The cumulative duration of treatment exposure was 44 participant-years and 18 participant-years for the WAYRILZ and placebo groups, respectively. Concomitant use of CS and/or TPO-RA with study drug occurred in 60% and 67% of patients in the WAYRILZ and placebo arms, respectively.
During the first 12 weeks of the DB period, 85 (63.9%) patients and 22 (31.9%) patients in the WAYRILZ group and placebo group, respectively, achieved platelet count response (≥50 × 10
The efficacy of WAYRILZ was based on durable platelet response. A durable platelet response was defined as a weekly platelet count ≥50 × 10
The results of the major efficacy endpoints during the DB period are summarized in Table 2.
Rescue medication was required by 33% and 58% of patients receiving WAYRILZ and placebo, respectively. The median time to first use of rescue therapy was not reached in the WAYRILZ group and 56 days in the placebo group.
During the OL period, 7/73 (10%) patients who received WAYRILZ during the DB period achieved a durable response for the first time.