The efficacy and safety of SEVENFACT for treatment of bleeding episodes was evaluated in Study 1, a global, multicenter, randomized, open-label, cross-over study (NCT02020369). The study enrolled 27 patients with hemophilia A or B with inhibitors who were treated for 468 bleeding events, of which 465 were mild or moderate and three were severe bleeding events.
The population characteristics were as follows: Mean age was 31 years (range 12 to 54 years) including five patients 12 to < 18 years of age who experienced 79 bleeding events. Patients were male, predominantly Caucasian (93%), median of 10 (range 3-50) bleeding episodes in six months prior to study enrollment. Overall, target joint(s)/bleeding site(s) were reported in 63% of patients at study entry.
Of the 468 bleeding events in diverse anatomic locations that were treated, 82% were spontaneous and the remaining (18%) were traumatic bleeding episodes; 465 were mild or moderate bleeding events and three were severe (refer to Table 5). The majority (98%) of bleeding events were treated at home, with 88% treated within one hour of recognition of bleeding.
Treatment Regimens for Mild or Moderate Bleeding Episodes
For mild to moderate bleeding episodes, patients were randomized to one of two initial dose regimens of SEVENFACT:
- 75 mcg/kg followed by subsequent doses of 75 mcg/kg every 3 hours as necessary to achieve hemostatic efficacy. A total of eight administrations were allowed in this dose regimen.
- 225 mcg/kg dose followed nine hours later with 75 mcg/kg doses every 3 hours as necessary to achieve hemostatic efficacy. A total of six administrations were allowed in this dose regimen.
Treatment with SEVENFACT was discontinued when bleeding persisted 24 hours after the first administration of SEVENFACT.
In Study 1, patients were randomized to one of two initial dosing regimens and continued on the dose regimen for three months, after which the patients were crossed over to the other dose regimen for three months.
Treatment Regimens for Severe Bleeding Episodes
Patients in the randomized study who experienced a severe bleed were administered the initial dose of 225 mcg/kg SEVENFACT at home, and were required to receive subsequent treatments at 75 mcg/kg every two hours in a hospital or hemophilia treatment center (HTC), if additional doses were considered necessary for treatment of ongoing bleeding. If response to treatment after the first or any subsequent administrations of study drug were satisfactory (i.e., efficacy assessment was rated as “good” or “excellent”), the dosing interval was changed from two hours to three hours for 1 to 2 days, after which the interval could be increased to 4 to 12 hours, depending on the severity of the bleeding episode, for as long as needed.
Bleeding Assessment
The primary endpoint of the study was successful treatment of mild or moderate bleeding episode at 12 hours after initial SEVENFACT dose administration. Success was defined by a combination of the following: patient’s response of “good” or “excellent” using a 4-point hemostatic efficacy scale (presented in Table 4), no further treatment with SEVENFACT beyond the 12-hour time point, no other hemostatic treatment needed for the bleeding episode, no administration of blood products, and no increase in pain beyond 12 hours.
Table 4
The 4-point Hemostatic Efficacy Scale Used to Assess Efficacy of Treatment| Patient and/or HCP* Evaluation | Therapeutic Response | Description |
| None | Lack of hemostatic efficacy | No noticeable effect of the treatment on the bleeding or worsening of patient’s condition. Continuation of treatment with the study drug was needed. |
| Moderate | Lack of hemostatic efficacy | Some effect of the treatment on the bleeding was noticed (e.g., pain decreased, or bleeding signs improved) but the bleeding continued and required continued treatment with the study drug. |
| Good | Hemostatic efficacy | Symptoms of the bleeding (e.g., swelling, tenderness, and decreased range of motion in the case of musculoskeletal hemorrhage) had largely been reduced by the treatment, but had not completely disappeared. Symptoms had improved enough to not require more infusions of the study drug. |
| Excellent | Hemostatic Efficacy | Full relief of pain and cessation of objective signs of the bleeding (e.g., swelling, tenderness, and decreased range of motion in the case of musculoskeletal hemorrhage). No additional infusion of study drug was required. |
| *Healthcare provider |
The primary efficacy analysis compared hemostatic efficacy of each dosing regimen with a prespecified objective performance criterion (OPC) of 55%. This OPC was based on historical data for hemostatic efficacy of bypassing agents. The study was powered to detect a 15% improvement over OPC for each dosing regimen. Results of the primary efficacy analysis are shown in Table 5.
Of the 465 mild or moderate bleeding episodes, 17 bleeding events were not evaluable due to missing a hemostatic efficacy assessment at 12 hours.
The proportion of mild or moderate bleeding events with hemostatic efficacy at 12 hours was 82% in the 75 mcg/kg dose regimen group and was 91% in the 225 mcg/kg dose regimen group.
Hemostatic efficacy was evaluated in 79 bleeding events in the five adolescent patients: for the 75 mcg/kg dose regimen, hemostatic efficacy was 93% (95% CI; 81%- 99%) and for the 225 mcg/kg dose regimen, it was 91% (95% CI; 77%-98%), with the confidence intervals given by the Clopper-Pearson exact method.
Table 5
Efficacy of SEVENFACT at 12 Hours for Treatment and Control of Mild or Moderate Bleeding Episodes | 75 mcg/kg (N=25)1 | 225 mcg/kg (N=25)1 | Overall (N=27)1 |
| Number of bleeding episodes | 252 | 213 | 465 |
| Number of bleeds with hemostatic efficacy | 197 (78.1%) | 188 (88.2%) | 385 (82.8%) |
| Number of failures | 44 (17.4.%) | 19 (8.9%) | 63 (13.5%) |
| Number of missing | 11 (4.3%) | 6 (2.8%) | 17 (3.7%) |
| Proportion of bleeds with hemostatic efficacy [95% CI]2 | 82% [72%, 91%] | 91% [84%, 98%] | 86% [78%, 93%] |
| p-value3 | <0.001 | <0.001 | |
1 N in the column header indicates number of patients who had at least 1 bleeding episode treated with a given dose of study drug. 2 Analysis was based on data as observed. No missing value imputation was made. 3 p-value from 1-sided normal approximation test of H0: p ≤0.55, where p is the true proportion of successfully treated mild or moderate bleeding episodes at 12 hours, with adjustment for the correlation among bleeding episodes for a given patient. The null hypothesis of hemostatic efficacy less than or equal to 55% was rejected. Note: Stratified by actual treatment regimen at the time of the bleeding episode. CI = confidence interval. |
The median and mean (SD) numbers of administrations per mild or moderate bleeding episode were 2.0 and 2.5 (1.75) for the 75 mcg/kg dose regimen and 1.0 and 1.4 (0.96) for the 225 mcg/kg dose regimen.
The median time to attain good or excellent assessment by the patient was six hours for the 75 mcg/kg dose regimen and three hours for the 225 mcg/kg dose regimen.
There were three severe bleeding episodes, of which one was a traumatic intramuscular bleeding episode and two were spontaneous bleeding episodes in the right hip and kidney. Hemostasis was achieved at 12 hours in the three severe bleeding events. One severe bleed was treated with three 225 mcg/kg doses administered every six hours, which was a deviation from the study protocol-specified dosing. The remaining two patients were treated with 1 and 5 doses of SEVENFACT respectively.
No patient received any alternative therapy prior to 24 hours. In addition, 97.6% of bleeding episodes treated with the 75 mcg/kg dose regimen, and 99.5% of bleeding episodes treated with the 225 mcg/kg dose regimen, did not require treatment with alternative bypassing agents.