The safety and efficacy of KOVALTRY for on-demand treatment and control of bleeding episodes, perioperative management of bleeding, and routine prophylaxis in subjects with severe hemophilia A (<1% Factor VIII) was evaluated in three international (including U.S.) clinical studies. Immunocompetent subjects with severe hemophilia A (Factor VIII activity 1%) and no history of Factor VIII inhibitors were eligible for the trials.
Study 1: a multi-center, open-label, cross-over, uncontrolled, study in adolescent and adult (age 12 years to <65 years) PTPs ( 150 EDs) evaluated the pharmacokinetics, efficacy and safety of routine prophylaxis, and perioperative management of bleeding of KOVALTRY (see Table 7). The primary efficacy variable was ABR. The prophylactic regimen was 20 to 50 IU/kg two or three times per week in which the dosing frequency was assigned by the investigator based on the subject s individual requirements.
Study 2: a multi-center, open-label, cross-over, uncontrolled, randomized study in adolescent and adult (age 12 years to <65 years) PTPs ( 150 EDs) evaluated the superiority of prophylaxis over on-demand treatment with KOVALTRY over a one-year treatment period (see Table 7). The primary efficacy variable was ABR. The prophylactic regimen was 20 to 30 IU/kg two times per week or 30 to 40 IU/kg three times per week and the treatment group was assigned by randomization.
Study 3: a multi-center, open-label, uncontrolled study in pediatric (age 12 years) PTPs ( 50 EDs) evaluated the pharmacokinetics, efficacy and safety of routine prophylaxis, and perioperative management of bleeding of KOVALTRY (see Table 8). The primary efficacy variable was annualized number of total bleeds during routine prophylaxis that occurred within 48 hours following previous prophylaxis infusion. ABR during prophylaxis, independent of time of infusion, was also analyzed. The prophylactic regimen was 25 to 50 IU/kg at frequencies of either 2 times per week, 3 times per week or every other day and could be adapted to individual subject s need by the investigator.
In all studies, treatments of breakthrough bleeds and perioperative management were at the investigator s discretion based on standard of care.
A total of 204 subjects were enrolled in the completed clinical trials, 153 subjects 12 years of age and 51 subjects <12 years of age. One hundred-forty (140) subjects were treated for at least 12 months, and 43 of these subjects were treated for 24 months.
Table 7: Overview of Study 1 (Prophylaxis Treatment Phase) and Study 2 | Study 1 (N=62) | Study 2 (N=80) |
Age: mean SD | 31.5 12.7 years | 29.6 11.0 years |
Previous treatment: % | Prophylaxis: 80.6% | On-demand: 100% |
Number of Target joints at baseline: mean SD | 1.4 1.3 | 3.0 2.1 |
Joint hemorrhage history (during 12 months prior to study): mean SD of joint bleeds | 8.0 11.9 | 32.1 23.8 |
Table 8: Overview of Study 3 | Study 3 |
PTPs 0 to <6 yrs (N=25) | PTPs 6 to 12 yrs (N=26) |
Age: mean SD (range) | 3.8 1.3 years (1-5) | 8.8 1.8 years (6-11) |
Previous treatment: % | Prophylaxis: 92.0% | Prophylaxis: 65.4% |
Number of Target joints at baseline: mean SD | 0.2 0.4 | 0.7 1.1 |
14.1 On-demand Treatment and Control of Bleeding Episodes
Adolescents and Adults
A total of 1892 bleeding episodes in 110 subjects were treated with KOVALTRY in Study 1 and Study 2 (see Table 9). The majority of the bleeding episodes were spontaneous, localized in joints, and mild to moderate in severity.
In Study 1 and Study 2, the treatment responses in a total of 1859 treated bleeds were assessed by the subjects compared to their previous treatment experience.
Table 9: On-demand Treatment and Control of Bleeding Episodes in Adolescents and Adults Treated with KOVALTRY |
Characteristics of Bleeding Episodes | Study 1 | Study 2 |
Prophylaxis Main Study N=62 | Prophylaxis Extension N=55 | Prophylaxis N=59 | On-demand N=21 |
Total number of bleeds | 241 | 154 | 293 | 1204 |
Spontaneous: n/total (%) | 153/241 (63.5%) | 79/150* (52.7%) | 209/283* (73.9%) | 943/1202* (78.5%) |
Trauma: n/total (%) | 79/241 (32.8%) | 70/150* (46.7%) | 74/283* (26.1%) | 258/1202* (21.5%) |
Joint bleeds: n/total (%) | 191/241 (79.3%) | 120/154 (77.9%) | 255/293 (87.0%) | 924/1197* (77.2%) |
Mild/moderate: n/total (%) | 215/241 (89.2%) | 130/153* (84.9%) | 260/293 (88.8%) | 1092/1196* (91.3%) |
% of bleeds treated with 2 infusions | 87.0% | 96.2% | 95.3% |
Response to treatment of bleeds assessed as Excellent or Good : n/total (%) | 190/235 (80.9%) | 107/149 (71.8%) | 172/279 (61.6%) | 834/1196 (69.7%) |
Median dose per infusion (range) | 31.6 IU/kg (14-67 IU/kg) | 29.4 IU/kg (19-49 IU/kg) | 22.0 IU/kg (11-35 IU/kg) |
Children 12 Years of Age and Younger
A total of 97 bleeding episodes in 28 pediatric subjects were treated with KOVALTRY. Majority (96.9%) of the bleeds were mild to moderate in severity. Fifty-nine (72.8%) bleeds were trauma related. During the 6 month treatment period, the median dose of KOVALTRY for the treatment of breakthrough bleeds was 36.94 IU/kg per infusion (range 20.8 71.6 IU/kg).
Assessment of response to treatment of bleeds was as follows:
Excellent: Abrupt pain relief and/or improvement in signs of bleeding with no additional infusion administered; Good: Definite pain relief and/or improvement in signs of bleeding but possibly requiring more than one infusion for complete resolution; Moderate: Probable or slight improvement in signs of bleeding with at least one additional infusion for complete resolution; Poor: No improvement at all between infusions or condition worsens.
The hemostatic efficacy in on-demand treatment of bleeds was assessed as either good or excellent in 90.1% of cases (97.8% in the younger age group and 81.0% in the older age group). Majority of bleeds (89.7%) were successfully treated with 2 infusions. Response to treatment was similar for children aged 0 to <6 compared to 6 to 12 years of age (see Table 10).
Table 10: On-demand Treatment and Control of Bleeding Episodes in Children Treated with KOVALTRY Characteristics of Bleeding Episodes | Study 3 |
PTPs 0 to <6 yrs (N=25) | PTPs 6 to 12 yrs (N=26) | PTPs 0 to 12 yrs (N=51) |
|
Total number of bleeds | 52 | 45 | 97 |
Spontaneous: n/total (%) | 8/44* (18.2%) | 12/37* (32.4%) | 20/81* (24.7%) |
Trauma: n/total (%) | 36/44* (81.8%) | 23/37* (62.2%) | 59/81* (72.8%) |
Joint bleeds: n/total (%) | 10/52 (19.2%) | 22/45 (48.9%) | 32/97 (33.0%) |
Mild/moderate: n/total (%) | 50/52 (96.2%) | 44/45 (97.8%) | 94/97 (96.9%) |
% of bleeds treated with 2 infusions | 92.4% | 86.7% | 89.7% |
Response to treatment of bleeds assessed as Excellent or Good : n/total (%) | 43/44 (97.8%) | 30/37 (81.0%) | 73/81 (90.1%) |
Median dose per infusion (range) | 38.7 IU/kg (20.8 71.6 IU/kg) | 32.4 IU/kg (21.7 50.0 IU/kg) | 36.9 IU/kg (20.8 71.6 IU/kg) |
14.2 Perioperative Management
A total of 14 major and 46 minor surgeries were performed in 44 previously treated subjects (43 adults and adolescents and 1 child under 12 years of age) with severe hemophilia A. Seven of the 14 major surgeries were orthopedic procedures, including joint replacement. Approximately 51% of the minor surgeries were dental extractions. All subjects received KOVALTRY as bolus infusions. In the adolescent and adult subjects, the initial KOVALTRY doses administered ranged between 3000 5000 IU. The median total dose on the day of surgery was 107.5 IU/kg (range 60 207 IU/kg). In a single subject younger than 12 years of age who underwent a major surgery, the total initial KOVALTRY dose administered was 2500 IU (108.7 IU/kg).
The blood loss, during and after surgery, was within expected ranges. Hemostatic control was assessed by surgeons as good (perioperative bleeding slightly but not clinically significantly increased over expectations for the non-hemophilic patient; treatment similar to non-hemophilic patient) or excellent (perioperative blood loss similar to the non-hemophilic patient).
14.3 Routine Prophylaxis
Adolescents and Adults
A total of 140 subjects were treated with KOVALTRY for at least 12 months with median (range) 157 EDs (25-178) in Study 1, [305 EDs (25-355) inclusive of extension phase], and 153 EDs (103-187) in Study 2 (see Table 11). In both studies, subjects in the Intent-to-Treat (ITT) population received 95% to 100% of the prescribed number of prophylaxis infusions.
Table 11: Prophylaxis Treatment with KOVALTRY in Adolescents and Adults Treatment Exposure | Study 1 (N=62)* | Study 2 (N=59) |
|
Median nominal prophylaxis dose/ infusion (range) All Prophylaxis 2 times per week Prophylaxis 3 times per week | 31.2 IU/kg (21-43 IU/kg) 35.0 IU/kg (21-42 IU/kg) 31.1 IU/kg (24-43 IU/kg) | 31.7 IU/kg (21-42 IU/kg) 30.4 IU/kg (21-34 IU/kg) 37.4 IU/kg (30-42 IU/kg) |
Treatment duration | 1 year main study | 1 year |
Study 1: 2 times per week (n=18); 3 times per week (n=44) Study 2: 2 times per week (n=28); 3 times per week (n=31) |
The mean and median ABR for the ITT population in Study 1 was 3.8 5.2 and 1 bleed/year, respectively. In Study 2, comparison of the bleeding rates between subjects receiving on-demand therapy versus prophylaxis in an ANOVA demonstrated a statistically significant difference (p<0.0001) in the median ABR in subjects receiving on-demand therapy (60 bleeds per year) as compared to subjects receiving prophylaxis (2 bleeds per year). In Study 2, mean ABR in subjects receiving on-demand therapy was 57.7 24.6 versus 4.9 6.8 in the subjects receiving prophylaxis.
Table 12: ABR in Adolescent and Adult Subjects |
| Study 1 (N=62) | Study 2 (N=59) |
| 2 times per week (n=18) | 3 times per week (n=44) | 2 times per week (n=28) | 3 times per week (n=31) |
ABR Median (IQR*Q1; Q3) | | | | |
-
- All Bleeds
| 1.0 (0.0; 8.0) | 2.0 (0.5; 5.0) | 4.0 (0.0; 8.0) Month 1-6 : 4.1; Month 7-12 : 1.1 | 2.0 (0.0; 4.9) Month 1-6 : 2.0; Month 7-12 : 2.0 |
-
- Spontaneous Bleeds
| 0.5 (0.0; 2.0) | 1.0 (0.0; 3.9) | 2.0 (0.0; 6.5) | 0.0 (0.0; 3.0) |
-
- Joint Bleeds
| 0.5 (0.0; 7.0) | 1.8 (0.0; 3.0) | 2.5 (0.0; 7.5) | 1.0 (0.0; 4.0) |
Subjects with Zero Bleeding Episodes % (n) | 37.5% (6/16 ) | 62.5% (10/16 ) | 28.6% (8/28 ) | 25.8% (8/31 ) |
The ABR for subjects (n=21) receiving on-demand therapy in Study 2 [median (IQR Q1; Q3)] for all bleeds: 60 (41.7; 76.3); spontaneous bleeds: 42.1 (24.3; 61.3); joint bleeds: 38.8 (24.3; 60.0).
Children 12 Years of Age and Younger
A total of 51 PTPs were treated with KOVALTRY for at least 6 months with median (range) 73 EDs (37-103) (see Table 13). Subjects received >95% of the prescribed number of prophylaxis infusions.
Table 13: Prophylaxis Treatment with KOVALTRY in Children 12 Years of Age or Younger Treatment Exposure | Study 3 |
PTPs 0 to <6 yrs (N=25) | PTPs 6 to 12 yrs (N=26) |
|
Treatment regimen* during study (6 months) n (%) 2 times per week 3 times per week or every other day | 9 (36%) 16 (64%) | 13 (50%) 13 (50%) |
Nominal prophylaxis dose per infusion, median (range) | 36.4 IU/kg (21-58 IU/kg) | 31.8 IU/kg (22-50 IU/kg) |
In children 12 years of age and younger (n=51), the median (IQR Q1; Q3) ABR within 48 hours after prophylactic infusion was 0 (0; 4) for all bleeds, and 0 (0; 0) for spontaneous and joint bleeds. The median (IQR Q1; Q3) ABR during prophylactic treatment independent of time of infusion was 1.9 (0; 6) for all bleeds, 0 (0; 0) for spontaneous bleeds and 0 (0; 2) for joint bleeds. The mean ABR within 48 hours after prophylactic infusion was 2.04 2.91. The mean ABR at any time during the prophylaxis regimen was 3.75 4.98.
In both age groups (0 to <6 years and 6 to 12 years), the ABR for spontaneous bleeds and joint bleeds within 48 hours after prophylactic treatment [ABR median (IQR Q1; Q3)] was 0 (0; 0). The median (IQR Q1; Q3) annualized number of spontaneous bleeds during prophylactic treatment independent of time of infusion was 0 (0; 0). The median (IQR Q1; Q3) annualized number of joint bleeds during prophylactic treatment independent of time of infusion was 0 (0; 1.9) in 0 to <6 years age group and 0 (0; 2.1) in 6 to 12 years age group (see Table 14).
The majority (32/53) of bleeds that occurred within 48 hours after a previous prophylaxis infusion were trauma related. Twenty-three (45.1%) subjects reported no bleeds during the six-month prophylaxis period.
Table 14: ABR in Children 12 Years of Age or Younger | Study 3 |
| PTPs 0 to <6 yrs (N=25) | PTPs 6 to 12 yrs (N=26) |
|
| Within 48 hrs after prophylactic treatment | During prophylactic treatment* | Within 48 hrs after prophylactic treatment | During prophylactic treatment* |
All Bleeds ABR Median (IQR Q1; Q3) | 1.9 (0.0; 4.0) | 2.0 (0.0; 6.0) | 0.0 (0.0; 2.0) | 0.9 (0.0; 5.8) |
Number of Subjects with Zero Bleeding Episodes (%) | 10 (40%) | 13 (50%) |