rgone a splenectomy. The patients had been diagnosed with ITP for approximately 2 years and had received a median of three prior ITP treatments. Overall, the median platelet count was 19 x 109/L at study entry. During the study, the median weekly Nplate dose was 2 mcg/kg (25th–75th percentile: 1–3 mcg/kg).
Study 2 eva luated patients who had undergone a splenectomy. The patients had been diagnosed with ITP for approximately 8 years and had received a median of six prior ITP treatments. Overall, the median platelet count was 14 x 109/L at study entry. During the study, the median weekly Nplate dose was 3 mcg/kg (25th–75th percentile:
2–7 mcg/kg).
Study 1 and 2 outcomes are shown in Table 3. A durable platelet response was the achievement of a weekly platelet count ≥ 50 x 109/L for any 6 of the last 8 weeks of the 24-week treatment period in the absence of rescue medication at any time. A transient platelet response was the achievement of any weekly platelet counts ≥ 50 x 109/L for any 4 weeks during the treatment period without a durable platelet response. An overall platelet response was the achievement of either a durable or a transient platelet response. Platelet responses were excluded for 8 weeks after receiving rescue medications.
Table 3: Results from Placebo-Controlled Studies* *
All P values < 0.05 for platelet response and rescue therapy comparisons between Nplate and placebo.
For multiple concomitant baseline therapies, all therapies were discontinued.
Outcomes Study 1
Nonsplenectomized Patients Study 2
Splenectomized Patients
Nplate
(n = 41)
Placebo
(n = 21)
Nplate
(n = 42)
Placebo
(n = 21)
Platelet Responses and Rescue Therapy
Durable Platelet Response, n (%) 25 (61%) 1 (5%) 16 (38%) 0 (0%)
Overall Platelet Response, n (%) 36 (88%) 3 (14%) 33 (79%) 0 (0%)
Number of Weeks With Platelet Counts ≥ 50 x 109/L, average 15 1 12 0
Requiring Rescue Therapy, n (%) 8 (20%) 13 (62%) 11 (26%) 12 (57%)
Reduction/Discontinuation of Baseline Concurrent ITP Medical Therapy
Receiving Therapy at Baseline (n = 11) (n = 10) (n = 12) (n = 6)
Patients Who Had > 25% Dose Reduction in Concurrent Therapy, n (%) 4/11
(36%) 2/10
(20%) 4/12
(33%) 1/6
(17%)
Patients Who Discontinued Baseline Therapy, n (%)† 4/11
(36%) 3/10
(30%) 8/12
(67%) 0/6
(0%)
In Studies 1 and 2, nine patients reported a serious bleeding event [five (6%) Nplate, four (10%) placebo]. Bleeding events that were grade 2 severity or higher occurred in 15% of patients treated with Nplate and 34% of patients treated with placebo.
Extension Study
Patients who had participated in either Study 1 or Study 2 were withdrawn from study medications. If platelet counts subsequently decreased to ≤ 50 x 109/L, the patients were allowed to receive Nplate in an open-label extension study with weekly dosing based on platelet counts. Following Nplate discontinuation in Studies 1 and 2, seven patients maintained platelet counts of ≥ 50 x 109/L. Among 100 patients who subsequently entered the extension study, platelet counts were increased and sustained regardless of whether they had received Nplate or placebo in the prior placebo-controlled studies. The majority of patients reached a median platelet count of 50 x 109/L after receiving one to three doses of Nplate, and these platelet counts were maintained throughout the remainder of the study with a median duration of Nplate t |
