The pivotal trials consisted of two phase 3, parallel, double-blind studies where patients with chronic immune thrombocytopenia (ITP) who had completed at least one prior treatment were randomized to Nplate® or placebo. The primary endpoint was the achievement of a durable platelet response, defined as a weekly platelet count ≥ 50 x 109/L for at least 6 of the last 8 weeks of the 24-week treatment period in the absence of rescue therapies at any time.
See the Nplate® pivotal trials information. Learn more >
Treatment with Nplate® or SOC was studied in a multicenter, randomized, controlled, 52-week, open-label evaluation of Nplate® and medical SOC therapy for non-splenectomized patients with ITP.
The design of this trial does not allow for comparison of Nplate® to the individual treatments received in the SOC arm.
- Co-primary endpoints were the incidence of treatment failure and splenectomy.
- Safety outcomes were measured as one of the secondary endpoints.
- Concomitant therapies were allowed for both treatment groups.
- To achieve a target platelet count of 50–200 x 109/L, Nplate® was administered once weekly at a starting dose* of 3 mcg/kg up to a maximum dose of 10 mcg/kg.
- Treatments for patients assigned to the SOC group were selected by the investigator according to standard institutional practices or therapeutic guidelines.
was also considered treatment failure.
≤ 20 x 109/L for 4 consecutive weeks at highest recommended dose of study treatment
due to side effects or bleeding symptoms
was also considered splenectomy
Therapies used in SOC arm2
Patients already receiving ITP therapies at baseline (21/157 in Nplate® group; 5/77 in SOC group) could continue receiving these throughout the trial.2
Other ITP treatments used in the Nplate® arm at any time during the 1-year trial included corticosteroids (37% of patients), immunoglobulins (7%), rituximab (1%), azathioprine (1%), danazol (2%), other medications‡ (6%), and platelet transfusions (6%). 2
Incidence of treatment failure at 1 year1
Results were consistent with those in pivotal phase 3 trial non-splenectomized patients.1-3
The percentage of patients on Nplate® achieving a platelet response (> 50 x 109/L) ranged from 71% (108/152) to 92% (127/138) at any scheduled visit (weeks 2-52).2
Review Nplate® or SOC trial safety information. Learn more >
Raise and sustain platelet counts in splenectomized patients1
Deliver platelet stability and durability1
Sustained median platelet count ≥ 50 x 109/L, 1,2
Median weekly platelet count includes all patients, even those receiving rescue therapy. Error bars indicate the range from the first to the third quartiles. Light-blue line indicates platelet count of 50 x 109/L.2
Comparable results were seen in non-splenectomized patients.2
Rate of grade 3 and above bleeding events2
Rate = adverse event rate per 100 patient-weeks on study medication. Rate was calculated by dividing the total number of reported events by the total number of patient-weeks and then multiplying by 100.2
Definitions of bleeding events grade 2 through 52
In the pivotal trial with non-splenectomized patients, 10% (4/42) of Nplate® patients vs 30% (6/20) of control patients experienced a grade 2§ or above bleeding event (P = 0.04)., 4,5 Bleeding events were captured as adverse events and were not a predefined endpoint in the pivotal trial.
†Rituximab is not FDA approved for use in ITP.
‡Including vincristine, cyclosporine, tranexamic acid, ascorbic acid, calcium, ethamsylate, pantoprazole, and Expasyl®.2 Expasyl® is a registered trademark and entire property of Pierre Rolland.
*The recommended starting dose for Nplate® is 1 mcg/kg. Please see Nplate® Prescribing Information for complete dosing instructions, including guidelines for dose adjustments. In the pivotal trials, the median dose of Nplate® was 2 mcg/kg (25th–75th percentile: 1–3 mcg/kg) in the study of non-splenectomized patients and 3 mcg/kg (25th–75th percentile: 2–7 mcg/kg) in the study of splenectomized patients.3
§Grading was per the Common Terminology Criteria for Adverse Events, v3. http://ctep.cancer.gov. 2