Objective:
Nonacog beta pegol (N9-GP) and recombinant factor IX-Fc fusion protein (rFIXFc) are two modified rFIX compounds with extended half-lives compared with standard FIX products. We report results from two head-to-head, single-dose pharmacokinetic (PK) trials comparing N9-GP with standard FIX and rFIXFc in previously-treated patients (PTPs) with congenital hemophilia B (≤2% FIX).
Methods:
paradigm™1 (NCT00956345) was a first human-dose trial in PTPs investigating the safety and PK of a single N9-GP dose. Sixteen PTPs (21-55 years) received one dose of their previous FIX product, followed by one dose of N9-GP at the same dose level (25, 50, or 100 IU/kg) with ≥7 days between doses. FIX activity was assessed up to 48 hours (standard FIX) or 168 hours (N9-GP) with additional samples at 2 and 4 weeks analyzed by one-stage clotting assay (TriniCLOT™) with product-specific standard as calibrator. paradigm™7 (NCT00956345) was a multicenter, randomized, head-to-head trial where 15 patients (21-65 years) received single injections (50 IU/kg) of N9-GP and rFIXFc with ≥21 days between doses. FIX activity was assessed for up to 240 hours using a one-stage clotting assay (SynthAFax or Actin FSL) and a chromogenic assay (ROX factor IX) with normal human plasma as calibrator. The primary endpoint was area under the FIX activity–time curve from 0 to infinity, dose normalized to 50 IU/kg (AUC0-inf,norm).
Summary:
In paradigm™1, the estimated terminal half-life of N9-GP was 93 hours, 4.8 times longer than for patients’ previous product. For N9-GP, estimated incremental recovery at 30 minutes (IR30min) (1.33 IU/dL per IU/kg) was 94% and 20% higher compared with rFIX and plasma-derived FIX (pdFIX), respectively. AUC0-inf,norm with N9-GP was 10.1 times and 7.7 times higher compared with rFIX and pdFIX, respectively. Time to 3% and 1% FIX activities was 16.2 and 22.5 days, respectively. In paradigm™7, the estimated AUC0-inf,norm measured with one-stage clotting assay was 4.4 times higher for N9-GP compared with rFIXFc (9656 versus 2199 IU*h/dL). IR30min was 2.2 times higher (1.7 versus 0.8 IU/dL per IU/kg), maximum activity, dose normalized to 50 IU/kg, was 2 times higher (91% versus 45%), and FIX activity at 168 hours was 5.8 times higher (19% versus 3%). N9-GP had a longer terminal half-life (103.2 versus 84.9 hours; ratio: 1.22). Results were similar when measuring FIX activity with chromogenic assay. One patient in paradigm™1 developed transient hypersensitivity symptoms during administration of N9-GP and was excluded from PK analyses. No patient developed inhibitors in either trial, and no unexpected safety concerns were identified.
Conclusion:
These two single-dose PK trials show that N9-GP achieves higher FIX activity levels and greater AUC than pdFIX, rFIX, and rFIXFc through higher recovery and longer terminal half-life. These findings will support clinicians’ understanding of differences in PK between specific FIX products.
Objective:
BAY 94-9027 is an extended–half-life recombinant factor VIII (FVIII) product. In the PROTECT VIII study, BAY 94-9027 provided effective protection against bleeds and was well tolerated with twice-weekly, every-5-day, and every-7-day prophylaxis in patients with severe hemophilia A. We report interim safety data from the PROTECT VIII extension study evaluating long-term outcomes in patients using BAY 94-9027 prophylaxis for >5 years .
Methods:
Previously treated patients aged 12 to 65 years with severe hemophilia A were enrolled in PROTECT VIII, in which they received BAY 94-9027 for 36 weeks on demand or as twice-weekly (30–40 IU/kg), every-5-day (45–60 IU/kg), or every-7-day (60 IU/kg) prophylaxis. Patients could subsequently participate in an extension study with the same or a different regimen. Adverse events (AEs), anti-PEG antibodies, inhibitor development, renal safety, and plasma PEG levels were evaluated during the extension phase.
Summary:
One hundred twenty-one of 134 patients from PROTECT VIII continued in the extension study receiving BAY 94-9027 either on demand (n=14) or as prophylaxis (n=107). At data cutoff (January 2018), patients aged 15 to 67 years at time of analysis (median age, 40 y) had a median (range) of 1420 (297–1965) days in the trial since enrollment and a median (range) of 223 (23–563) exposure days . Prophylaxis patients were treated either twice weekly (n=23), every 5 days (n=33), every 7 days (n=23), or switched frequency during the extension (n=28) . Overall, 9 patients (7.4%) experienced treatment-related AEs during the extension classified as either mild (n=4), moderate (n=4), or severe (n=1) . Two patients (1.7%) experienced 3 SAEs considered to be treatment-related (elevated liver function tests in a patient with hepatitis C ; 2 incidences of back pain); these 2 patients discontinued the study. Transient low-titer anti-PEG antibodies were detected at a single visit in 8 patients but were not associated with clinical events. No patients developed FVIII inhibitors or had sustained levels of detectable PEG in plasma . No specific changes in renal parameters were observed.
Conclusions:
During the ongoing PROTECT VIII extension, BAY 94-9027 prophylaxis was well tolerated for >5 years, and no patients developed FVIII inhibitors.
Objective:
Report results of an open-label international study that collected retrospective data on compassionate use of high-purity plasma-derived FX concentrate (pdFX) in subjects with hereditary factor X (FX) deficiency (FXD).
Methods:
This study included subjects with hereditary FXD (irrespective of severity) who received compassionate use pdFX as routine prophylaxis (RP), on-demand (OD) treatment, short-term prevention, and/or perisurgical hemostatic cover. Dosing was at the investigator’s discretion and tailored to each patient. Data from date of first compassionate use dose until data cutoff (31 December 2015) were collected retrospectively.
Summary:
All 15 enrolled subjects from 12 study centers received ≥1 pdFX dose for compassionate use. Of these, 13 subjects were aged ≥12 years (mean, 22.8 years) and 2 were aged <12 years, 8 (53.3%) were female, 12 (80.0%) were white, 3 (20.0%) were Asian. All subjects had moderate or severe FXD (FX activity [FX:C] <5 IU/dL).Of the 15 patients, 7 received only RP, 7 received only OD, and 1 alternated between OD and RP. The 8 subjects on RP received a total of 1239 RP infusions (mean, 154.9 infusions/subject, range 39–492), with a mean dose/infusion/subject of 32.5 IU/kg. The 2 subjects aged <12 years received larger RP doses than the 6 older subjects (mean doses/infusion/subject of 51.1 vs 26.3 IU/kg).Twelve subjects (8 OD, 4 RP; all aged ≥12 years) reported 88 bleeds (34 minor, 7 major, and 47 not rated); 37 bleeds were menorrhagic, 28 were traumatic, 17 were spontaneous, 4 were other, and 2 had unknown cause. pdFX efficacy was rated as effective for the 79 bleeds (including 1 subdural hematoma) treated with OD pdFX. Mean pdFX dose was 22.2 IU/kg/infusion/subject, with a mean of 9.5 infusions/subject to treat a bleed. More bleeds occurred in the OD than in the RP population.Two subjects underwent 1 dental procedure each, with only 1 presurgical pdFX dose required per patient; a third surgery, a portacath insertion, required 6 infusions to prevent postoperative bleeding. Two successful pregnancies/childbirths were also reported, with no abnormal bleeding complications or efficacy/safety concerns reported.The mean duration of compassionate use was 87.6 weeks for the 15 subjects, with a range of 15–211 weeks (0.3–4.0 years). Over the 1373 infusions administered across 25.2 subject-years, investigators rated overall pdFX efficacy as excellent in 14 (93.3%) subjects and good in 1 (6.7%) subject. No adverse drug reactions, safety concerns, infusion site reactions, tolerability issues, or inhibitor development were reported during pdFX compassionate use.
Conclusions:
The higher bleed rate in OD versus RP use and the treatment duration (up to 4 years) support the efficacy and safety of pdFX demonstrated in prospective clinical studies and its continued use in the treatment of subjects with hereditary FXD.
