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Vials and a syringe

BERLIN—Results of a phase 3 study suggest prophylaxis with plasma-derived factor X (pdFX, Coagadex®) prevents or reduces bleeding episodes in children with moderate to severe hereditary factor X deficiency (FXD).

pdFX was well tolerated in this study as well, with no treatment-related adverse events (AEs) reported.

“For the first time, we have data providing physicians with important evidence of the efficacy and safety of Coagadex as a prophylactic regimen for the reduction and prevention of bleeding episodes, as well as potential guidance on dosing for children with hereditary factor X deficiency,” said Michael Gattens, MBChB, a consultant pediatric hematologist at Cambridge University Hospitals in the UK and an investigator involved in this trial.

Data from the trial, known as TEN02, were presented in a poster (PB 818) at the International Society on Thrombosis and Haemostasis (ISTH) 2017 Congress. The trial was sponsored by Bio Products Laboratory Limited.

TEN02 was a prospective study conducted in children younger than 12 years with moderate or severe congenital FXD (basal plasma factor X activity <5 IU/dL at diagnosis) and either a history of severe bleeding or an F10 gene mutation causing a documented severe bleeding type.

The study enrolled 9 patients. Eight had severe FXD (FX:C <1 IU/dL), and 1 had moderate FXD (FX:C 1–5 IU/dL).

The patients’ mean age was 7.3 (range, 2.6 years to 11.9 years). Four patients were in the 0-5 age group, and 5 were in the 6-11 age group. Fifty-six percent of patients were female, 78% were Asian, and 22% were white.

The patients had a total of 21 prior bleeds, including overt (n=10), covert (n=9), and menorrhagic (n=2). The past bleeds were spontaneous (n=16) or caused by injury (n=2), menorrhagia (n=2), or surgery (n=2).

Treatment

Patients received 50 IU/kg of pdFX at visit 1 (baseline), followed 72 hours later by a second dose (visit 2). At the investigator’s discretion, visit 2 may have been conducted 48 hours after the first dose for subjects ages 0 to 5.

Following visit 2, patients used pdFX at 40-50 IU/kg as routine prophylaxis every 72 ± 2 hours or every 48 ± 2 hours for those age 0 to 5, at the investigator’s discretion. Dose and frequency were adjusted over the initial 6 weeks to maintain FX:C levels ≥5 IU/dL (with peak levels ≤120 IU/dL).

Treatment was continued for at least 26 weeks, with a minimum of 50 treatment days.

Following visit 2, patients returned to the study site for 3 additional visits (after 9-28, 29-42, and 50 treatment days/26 weeks; visits 3-5), during which time blood samples were collected to assess FX:C trough levels and vital signs and AEs were checked.

A final bolus dose of 50 IU/kg was administered during visit 5 to assess post-dose incremental recovery.

A dose of 25 IU/kg was recommended to treat minor bleeds, and 50 IU/kg was recommended for major bleeds. Treatment was to be repeated as often as necessary based on FX:C recovery levels and clinical need.

Nine patients completed 11 treatment cycles, including 2 patients who had 50 exposure days but less than 26 study weeks. These patients were re-screened and completed a second, per-protocol treatment cycle.

Results

A total of 537 prophylactic infusions were administered, with a mean dose of 38.6 IU/kg per patient.

Investigators rated the prophylactic efficacy of pdFX as “excellent.”

There were 10 bleeds in 3 patients. Four bleeds in 2 patients (both in the 6-11 age group) required treatment with a single infusion of pdFX (mean dose, 31.7±10.1 IU/kg).

The overall mean 30-minute incremental recovery was 1.66 IU/dL per IU/kg for patients’ baseline visit, 1.82 IU/dL per IU/kg for the end-of-study visit, and 1.74 IU/dL per IU/kg for both visits combined.

Incremental recovery was significantly lower in the 0-5 age group than the 6-11 age group:

  • 1.45 vs 1.83 at baseline (P=0.027)
  • 1.62 vs 1.99 at end of study (P=0.025)
  • 1.53 vs 1.91 combined (P=0.001).

All patients had FX:C trough levels greater than 5% after visit 4 (days 29-42).

There were 28 AEs reported in 8 patients, but none of these events were considered related to treatment.

One patient did have 2 serious treatment-emergent AEs—lower respiratory tract infection and influenza.

There were no other serious AEs, no evidence of factor X inhibitor development, and no deaths.


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